Engine braking with a cold engine - bad idea?
March 7, 2012 10:00 AM Subscribe
Engine braking with a cold engine - bad idea?
Car: 2003 Volkswagen Golf, manual transmission. 2.0 L 4 cylinder non-turbo.
I go skiing several times a week, every week of the winter. When finished, the drive home begins with a 15-minute descent down the mountain.
I was in the habit of popping it into 3rd immediately and relying on engine braking most of the way. I recently noticed that the engine didn't seem to be warming up during the descent, and only started warming up when I reached the flats and had to start using the gas pedal.
So, two questions:
- is it not warming up during the descent because of "deceleration fuel cut off"?
- is it bad to do engine braking for 10+ minutes immediately after a cold start? Especially since the outside temperature is around freezing?
Car: 2003 Volkswagen Golf, manual transmission. 2.0 L 4 cylinder non-turbo.
I go skiing several times a week, every week of the winter. When finished, the drive home begins with a 15-minute descent down the mountain.
I was in the habit of popping it into 3rd immediately and relying on engine braking most of the way. I recently noticed that the engine didn't seem to be warming up during the descent, and only started warming up when I reached the flats and had to start using the gas pedal.
So, two questions:
- is it not warming up during the descent because of "deceleration fuel cut off"?
- is it bad to do engine braking for 10+ minutes immediately after a cold start? Especially since the outside temperature is around freezing?
1: Yes. With no combustion there is no heat. Engine braking is purely compression and so no heat will be produced.
2: Yes, pretty much. You should warm the car until it is out of the blue section at the very least as it thins the oil and gets all the tolerances somewhere close. It will accelerate wear to do that much cold engine braking. Turbos in particular don't like thick oil, even when not under load.
So... bad idea.
in my 00" Jetta (manual) I would not always get a correct reading on my engine temperature if the car was on an incline.
I cannot think of any possible reason that this is true without the gauge reading incorrectly through the physical action of the needle (which is phenomenally unlikely). The temperature gauge is situated inside a water system that is at pressure. There's no way the level of the water can move away form the sensor and give an incorrect reading just for an incline unless the car is upside down (and even then I doubt it). If this is genuine behaviour of your car, not just something you have falsely assumed cause and effect for some reason - then something is seriously amiss with the system in a totally freak way - maybe something leaning against the sender and shorting it out? It is certainly not a behaviour that will be attributable to any other Jetta/Golf/other car of any manufacturer that I can imagine.
posted by Brockles at 10:16 AM on March 7, 2012
2: Yes, pretty much. You should warm the car until it is out of the blue section at the very least as it thins the oil and gets all the tolerances somewhere close. It will accelerate wear to do that much cold engine braking. Turbos in particular don't like thick oil, even when not under load.
So... bad idea.
in my 00" Jetta (manual) I would not always get a correct reading on my engine temperature if the car was on an incline.
I cannot think of any possible reason that this is true without the gauge reading incorrectly through the physical action of the needle (which is phenomenally unlikely). The temperature gauge is situated inside a water system that is at pressure. There's no way the level of the water can move away form the sensor and give an incorrect reading just for an incline unless the car is upside down (and even then I doubt it). If this is genuine behaviour of your car, not just something you have falsely assumed cause and effect for some reason - then something is seriously amiss with the system in a totally freak way - maybe something leaning against the sender and shorting it out? It is certainly not a behaviour that will be attributable to any other Jetta/Golf/other car of any manufacturer that I can imagine.
posted by Brockles at 10:16 AM on March 7, 2012
Doesn't engine braking at all accelerate wear? And since it's much cheaper to replace your brakes than to replace the clutch, I thought the most practical (albeit the least fun) thing to do was to always use your brakes, and never engine brake.
posted by Grither at 10:23 AM on March 7, 2012
posted by Grither at 10:23 AM on March 7, 2012
Doesn't engine braking at all accelerate wear?
Not at all. This is completely incorrect. Engine braking is a perfectly sensible method of driving and doesn't wear the engine any more than driving it does.
posted by Brockles at 10:25 AM on March 7, 2012 [1 favorite]
Not at all. This is completely incorrect. Engine braking is a perfectly sensible method of driving and doesn't wear the engine any more than driving it does.
posted by Brockles at 10:25 AM on March 7, 2012 [1 favorite]
Oh, I missed this bit: "And since it's much cheaper to replace your brakes than to replace the clutch"
Engine braking doesn't make any difference at all to clutch wear either. There is no real downside to engine braking at all.
posted by Brockles at 10:26 AM on March 7, 2012 [1 favorite]
Engine braking doesn't make any difference at all to clutch wear either. There is no real downside to engine braking at all.
posted by Brockles at 10:26 AM on March 7, 2012 [1 favorite]
Response by poster: Can anyone confirm with specific knowledge that "deceleration fuel cut off" is happening? I.e. is this a standard behavior in this Golf's ECU?
I imagine car forums would be better for this, but I am not familiar with any of them.
posted by wutangclan at 10:28 AM on March 7, 2012
I imagine car forums would be better for this, but I am not familiar with any of them.
posted by wutangclan at 10:28 AM on March 7, 2012
Cheaper to replace the clutch than the car after your brakes boil and fail on you, too. Engine braking is perfectly reasonable, but I'd let the engine warm up for a few minutes first, if for no reason other than comfort, frankly.
posted by Kyol at 10:29 AM on March 7, 2012
posted by Kyol at 10:29 AM on March 7, 2012
Further on Grither's comment, the only part of engine braking that "uses" the clutch is actually letting out on the clutch. Once it's locked up, you're not "using" it at all. Which is why friction materials on a clutch are much thinner (used less) than those on the brakes. (for sporty driving, engine braking instead of brake-braking also means you don't have to change pedals when you want to get on the gas; you're already there!)
More to the point of the question, yes, let your car idle a bit to warm up. Maybe put it in second so you have to just barely stay on the throttle for a bit and warm the engine up.
(I must say, though, that I'm surprised engine braking doesn't do a decent job of warming the engine up to operating temperature - all that compression, especially in a turbo!)
posted by notsnot at 10:31 AM on March 7, 2012
More to the point of the question, yes, let your car idle a bit to warm up. Maybe put it in second so you have to just barely stay on the throttle for a bit and warm the engine up.
(I must say, though, that I'm surprised engine braking doesn't do a decent job of warming the engine up to operating temperature - all that compression, especially in a turbo!)
posted by notsnot at 10:31 AM on March 7, 2012
Response by poster: OK, further question: how do you warm up the engine on a long descent? Remember that I am going straight into the descent from a cold start. Do I coast down the hill in neutral and let the engine warm up at idle?
posted by wutangclan at 10:32 AM on March 7, 2012
posted by wutangclan at 10:32 AM on March 7, 2012
Response by poster: all that compression, especially in a turbo!
Like I said, it's NOT a turbo.
posted by wutangclan at 10:33 AM on March 7, 2012
Like I said, it's NOT a turbo.
posted by wutangclan at 10:33 AM on March 7, 2012
how do you warm up the engine on a long descent?
You probably don't. Either you find some non-downhill detour to start, or you leave it on and let it idle for a bit before you start driving at all.
posted by brainmouse at 10:41 AM on March 7, 2012
You probably don't. Either you find some non-downhill detour to start, or you leave it on and let it idle for a bit before you start driving at all.
posted by brainmouse at 10:41 AM on March 7, 2012
Does sitting in the parking lot for a few minutes with the engine running not count as "warming up"? I mean, if it does, why not just do that?
posted by rtha at 10:42 AM on March 7, 2012
posted by rtha at 10:42 AM on March 7, 2012
Can anyone confirm with specific knowledge that "deceleration fuel cut off" is happening? I.e. is this a standard behavior in this Golf's ECU?
I can't, but this is easy enough to verify. You can buy a Scangauge or Ultragauge and it will show the fuel usage at a given moment.
Alternatively, there are smartphone utilities such as Torque that when paired with a bluetooth OBDII scanner can report a lot more info about the engine's operating state.
As for your question, the concern I have would be restricted oil flow. Some engines have a variable pump and are built to accommodate cold running oils supply. I would bet your car is. If I had any doubt, I'd let the car idle for 5-10 minutes before heading down the mountain.
posted by Pogo_Fuzzybutt at 10:45 AM on March 7, 2012
I can't, but this is easy enough to verify. You can buy a Scangauge or Ultragauge and it will show the fuel usage at a given moment.
Alternatively, there are smartphone utilities such as Torque that when paired with a bluetooth OBDII scanner can report a lot more info about the engine's operating state.
As for your question, the concern I have would be restricted oil flow. Some engines have a variable pump and are built to accommodate cold running oils supply. I would bet your car is. If I had any doubt, I'd let the car idle for 5-10 minutes before heading down the mountain.
posted by Pogo_Fuzzybutt at 10:45 AM on March 7, 2012
Just start it up, run it for a few minutes in neutral, give it a gentle, sustained rev a few times, and then get going. It's as simple as that.
posted by clockzero at 10:48 AM on March 7, 2012
posted by clockzero at 10:48 AM on March 7, 2012
Response by poster: Does sitting in the parking lot for a few minutes with the engine running not count as "warming up"?
Impatience be damned, I guess that's the only option. Thanks all.
posted by wutangclan at 10:49 AM on March 7, 2012
Impatience be damned, I guess that's the only option. Thanks all.
posted by wutangclan at 10:49 AM on March 7, 2012
Best answer: Can anyone confirm with specific knowledge that "deceleration fuel cut off" is happening? I.e. is this a standard behavior in this Golf's ECU?
Yes. This is standard behaviour on any petrol ECU. Engine braking is zero fuel. Diesels aren't necessarily zero fuel, but petrol cars are. You don't need any extra gauges for this to be considered fact.
how do you warm up the engine on a long descent?
You can't really. You have to idle it for 5-10 minutes before leaving. At freezing temps that will also give the side effect of a working heater... Sustained revving of the engine also won't make much difference unless you hold it at 2000rpm or more for about 25% less time than just sitting it idling. It's not worth the annoying noise, so just leave it idling. The extra revs (with no load) don't really produce much more heat.
Do I coast down the hill in neutral and let the engine warm up at idle?
Good god, no. It is extremely bad practice to drive in neutral at all, especially downhill. The only time I'd ever suggest anyone drives at all in neutral is on a flat, straight bit of road to save (a tiny amount) of fuel.
I must say, though, that I'm surprised engine braking doesn't do a decent job of warming the engine up to operating temperature - all that compression
Compression doesn't really warm anything but the stuff going straight out the exhaust. It's not in there long enough to warm the engine, really. Also, a bit of squeezing is nothing in terms of heat compared to a fossil fuel explosion...
posted by Brockles at 11:07 AM on March 7, 2012
Yes. This is standard behaviour on any petrol ECU. Engine braking is zero fuel. Diesels aren't necessarily zero fuel, but petrol cars are. You don't need any extra gauges for this to be considered fact.
how do you warm up the engine on a long descent?
You can't really. You have to idle it for 5-10 minutes before leaving. At freezing temps that will also give the side effect of a working heater... Sustained revving of the engine also won't make much difference unless you hold it at 2000rpm or more for about 25% less time than just sitting it idling. It's not worth the annoying noise, so just leave it idling. The extra revs (with no load) don't really produce much more heat.
Do I coast down the hill in neutral and let the engine warm up at idle?
Good god, no. It is extremely bad practice to drive in neutral at all, especially downhill. The only time I'd ever suggest anyone drives at all in neutral is on a flat, straight bit of road to save (a tiny amount) of fuel.
I must say, though, that I'm surprised engine braking doesn't do a decent job of warming the engine up to operating temperature - all that compression
Compression doesn't really warm anything but the stuff going straight out the exhaust. It's not in there long enough to warm the engine, really. Also, a bit of squeezing is nothing in terms of heat compared to a fossil fuel explosion...
posted by Brockles at 11:07 AM on March 7, 2012
Response by poster: It is extremely bad practice to drive in neutral at all, especially downhill.
Bad from what standpoint? Safety?
posted by wutangclan at 12:04 PM on March 7, 2012
Bad from what standpoint? Safety?
posted by wutangclan at 12:04 PM on March 7, 2012
No fuel is injected while engine braking. That's just how it works. Not that you need this confirmed, but I can confirm that this is the behaviour of a diesel Jetta of similar vintage.
Personally (and this is something I have done, living on top of a hill with an engine that takes a long time to warm up), I would be willing to do some very gentle engine braking (i.e. keeping the revs very low, possibly in 4th) and then use the brakes on top of that. This probably does cause slightly more wear, but my car takes much more than a few minutes to warm up at idle anyways, so I don't have a better option.
I would not suggest putting the car in second if you normally use third. While using a bit of fuel will warm the engine up faster, in order to descend this hill in second, you'll be revving the engine quite high, which is not a great idea for a cold engine.
posted by ssg at 12:07 PM on March 7, 2012
Personally (and this is something I have done, living on top of a hill with an engine that takes a long time to warm up), I would be willing to do some very gentle engine braking (i.e. keeping the revs very low, possibly in 4th) and then use the brakes on top of that. This probably does cause slightly more wear, but my car takes much more than a few minutes to warm up at idle anyways, so I don't have a better option.
I would not suggest putting the car in second if you normally use third. While using a bit of fuel will warm the engine up faster, in order to descend this hill in second, you'll be revving the engine quite high, which is not a great idea for a cold engine.
posted by ssg at 12:07 PM on March 7, 2012
Bad from what standpoint? Safety?
Control generally, but especially in terms of wheel locking. The engine momentum will force the wheels to keep turning and prevent wheel locking and allow you to retain steering control. ABS will also prevent the wheels locking, but a free-running wheel has much less momentum so is able to lock sooner - and much more suddenly - than a wheel that is still connected to the driveline.
Turning wheels are always better able to grip than locked ones, and an engine-braked, slowly turning, wheel is even preferable to a pulsing ABS wheel. It's best to save ABS for when you REALLY need it, rather than using it to fill in the safety margin that better driving technique could be filled with.
posted by Brockles at 12:36 PM on March 7, 2012
Control generally, but especially in terms of wheel locking. The engine momentum will force the wheels to keep turning and prevent wheel locking and allow you to retain steering control. ABS will also prevent the wheels locking, but a free-running wheel has much less momentum so is able to lock sooner - and much more suddenly - than a wheel that is still connected to the driveline.
Turning wheels are always better able to grip than locked ones, and an engine-braked, slowly turning, wheel is even preferable to a pulsing ABS wheel. It's best to save ABS for when you REALLY need it, rather than using it to fill in the safety margin that better driving technique could be filled with.
posted by Brockles at 12:36 PM on March 7, 2012
I'm having trouble appreciating the risk of engine braking on a cold engine. Although it is true that the oil will be slightly less viscous, I find it hard to imagine that it would lead to lubrication failures. I've always understood that 85% or more of engine wear occurs during cold start (when the engine is essentially dry) and that once the pump is cranking, wear is not a significant concern in normal temperature ranges. If you are using an appropriate weight of oil, I would have no concern about lubrication failures related to engine temps once the engine has been running a few seconds, unless you were talking about temps well below 0F. Although the engine will not be fully warm for quite a few minutes, it will get warmer than the ambient atmospheric temp quite quickly and its flow characteristics will be fine.
The problem with engine braking once upon a time was that it leads to ejecting minute quantities of oil out the exhaust ports which could lead to catalytic converter damage over time. This problem is essentially solved (if indeed it really was a problem, which is the subject of some dispute) by the API SM standard or by using synthetic oils. These guys do a pretty good job of breaking down the SM/synthetic catalytic converter issue.
I also believe that if you don't ride the brake constantly, but just brake appropriately when entering a corner or when your speed threatens to get too high, you are unlikely to experience excessive brake temps or brake failure either.
posted by Lame_username at 1:16 PM on March 7, 2012
The problem with engine braking once upon a time was that it leads to ejecting minute quantities of oil out the exhaust ports which could lead to catalytic converter damage over time. This problem is essentially solved (if indeed it really was a problem, which is the subject of some dispute) by the API SM standard or by using synthetic oils. These guys do a pretty good job of breaking down the SM/synthetic catalytic converter issue.
I also believe that if you don't ride the brake constantly, but just brake appropriately when entering a corner or when your speed threatens to get too high, you are unlikely to experience excessive brake temps or brake failure either.
posted by Lame_username at 1:16 PM on March 7, 2012
Response by poster: FYI, the typical outside temperature around here will be -5C to +5C (yay, black ice).
posted by wutangclan at 2:17 PM on March 7, 2012
posted by wutangclan at 2:17 PM on March 7, 2012
I've always understood that 85% or more of engine wear occurs during cold start (when the engine is essentially dry) and that once the pump is cranking, wear is not a significant concern in normal temperature ranges.
You've totally answered your own question if you read your own sentence correctly:
I've always understood that 85% or more of engine wear occurs during cold start
It isn't during cranking alone, but when the engine is cold. Maybe the 'start' wording makes you think that it is purely when the engine cranks and initially fires. Engines are made up of different kinds of materials that expand at differing rates. Gaps between moving components will increase or decrease depending on the relative materials and the engine is designed to have these tolerances at optimum only when in the normal operating range. Also, gaps that are smaller do not get sufficient quantities of the thicker oil when it is cold and rub against each other more. The first 50-10 mins of running can be considered 'cold running' to progressively lesser amounts until the engine is fully warm through (ie not just the combustion chamber being hot).
wear is not a significant concern in normal temperature ranges.
Well... no. That is correct. But until the engine is warm, the car is not in the normal temperature ranges. That's only when it is in the middle 40% of the temp gauge (+/- 20% of centre). So you can accept that wear at normal ranges is not an issue, but is an issue at cold, yet can't understand how loading an engine when cold causes more wear. I'm confused how you can't take that understanding and apply it correctly, to be honest.
Engine braking is loading the car just as much as hammering the throttle and racing up and down the gearbox is. Conventional wisdom is to drive gently while cold (correctly) and engine braking is a similar load case to be avoided in the same way.
posted by Brockles at 2:28 PM on March 7, 2012
You've totally answered your own question if you read your own sentence correctly:
I've always understood that 85% or more of engine wear occurs during cold start
It isn't during cranking alone, but when the engine is cold. Maybe the 'start' wording makes you think that it is purely when the engine cranks and initially fires. Engines are made up of different kinds of materials that expand at differing rates. Gaps between moving components will increase or decrease depending on the relative materials and the engine is designed to have these tolerances at optimum only when in the normal operating range. Also, gaps that are smaller do not get sufficient quantities of the thicker oil when it is cold and rub against each other more. The first 50-10 mins of running can be considered 'cold running' to progressively lesser amounts until the engine is fully warm through (ie not just the combustion chamber being hot).
wear is not a significant concern in normal temperature ranges.
Well... no. That is correct. But until the engine is warm, the car is not in the normal temperature ranges. That's only when it is in the middle 40% of the temp gauge (+/- 20% of centre). So you can accept that wear at normal ranges is not an issue, but is an issue at cold, yet can't understand how loading an engine when cold causes more wear. I'm confused how you can't take that understanding and apply it correctly, to be honest.
Engine braking is loading the car just as much as hammering the throttle and racing up and down the gearbox is. Conventional wisdom is to drive gently while cold (correctly) and engine braking is a similar load case to be avoided in the same way.
posted by Brockles at 2:28 PM on March 7, 2012
To add to what Brockles says, bear in mind that an engine operates in a relatively tiny temperature range, you're looking at a range of materials (aluminum, iron, steel, ceramics, etc, cast vs. forged, etc) all of which expand at different rates and have different wear characteristics at different temperatures. Clearances in there are very tight.
There's a lot of translating rotation to linear motion in an engine. Things that are supposed to go straight up and down do not go straight up and down when there's enough clearance for them to wiggle around. This is bad.
posted by pjaust at 4:48 PM on March 7, 2012
There's a lot of translating rotation to linear motion in an engine. Things that are supposed to go straight up and down do not go straight up and down when there's enough clearance for them to wiggle around. This is bad.
posted by pjaust at 4:48 PM on March 7, 2012
My understanding of things completely aligns with Brockles, and he's stated things quite well.
I have a ScanGaugeII in my Yaris and years of use have confirmed all of the things mentioned here, notably that fuel use in a downhill+transmission engaged+foot off the pedal situation is zero.
So, where do people think that heat required for the engine to 'warm up' is coming from in that use case? I'm a mechanical engineer by education and can only think of two sources: combustion and internal friction. Without calculating things, I can't help but lean VERY far towards saying that combustion provides the vast majority of heat generated in this situation. Since you're not getting combustion during the descent, your engine probably isn't heating up to a serviceable temperature. Hence, oil isn't circulating as well as it could. I think your concern is valid, doubly so if a turbo is involved.
TL;DR: Let the car warm up in the parking spot for 3-4 mins (or longer, I'm not in the temperatures you are, a ScanGauge is a GREAT investment for this very reason) and then proceed down the hill and engine break away.
posted by RolandOfEld at 8:43 AM on March 8, 2012
I have a ScanGaugeII in my Yaris and years of use have confirmed all of the things mentioned here, notably that fuel use in a downhill+transmission engaged+foot off the pedal situation is zero.
So, where do people think that heat required for the engine to 'warm up' is coming from in that use case? I'm a mechanical engineer by education and can only think of two sources: combustion and internal friction. Without calculating things, I can't help but lean VERY far towards saying that combustion provides the vast majority of heat generated in this situation. Since you're not getting combustion during the descent, your engine probably isn't heating up to a serviceable temperature. Hence, oil isn't circulating as well as it could. I think your concern is valid, doubly so if a turbo is involved.
TL;DR: Let the car warm up in the parking spot for 3-4 mins (or longer, I'm not in the temperatures you are, a ScanGauge is a GREAT investment for this very reason) and then proceed down the hill and engine break away.
posted by RolandOfEld at 8:43 AM on March 8, 2012
I really hate calling attention to my own dimness, but I'm having a hard time reconciling this:
Engine braking is a perfectly sensible method of driving and doesn't wear the engine any more than driving it does.
with/vs. this:
Engine braking is loading the car just as much as hammering the throttle and racing up and down the gearbox is. Conventional wisdom is to drive gently while cold (correctly) and engine braking is a similar load case to be avoided in the same way.
(I do get that it's a really bad idea to stress an engine before it's warmed -- I'm not that dim)
posted by Tuesday After Lunch at 9:32 AM on March 8, 2012
Engine braking is a perfectly sensible method of driving and doesn't wear the engine any more than driving it does.
with/vs. this:
Engine braking is loading the car just as much as hammering the throttle and racing up and down the gearbox is. Conventional wisdom is to drive gently while cold (correctly) and engine braking is a similar load case to be avoided in the same way.
(I do get that it's a really bad idea to stress an engine before it's warmed -- I'm not that dim)
posted by Tuesday After Lunch at 9:32 AM on March 8, 2012
Very hard engine braking is the same as very hard driving. Gentle engine braking is the same as normal driving. I can kind of see how you think they contradict, but they don't really. The engine braking equivalent of 'gentle driving while the car warms up' won't actually slow the car very much at all so I think it is safe to assume that the engine braking in this circumstance is greater than 'the equivalent loading of gently driving.
High load cases wear more than low load cases, cold engines wear more than hot engines. It's all interrelated but those statements don't at all contradict. The difference in the two situations is that to get any decent engine braking effect you are producing similar load cases to driving up a steep hill and that should be avoided while the engine is cold, too. Just as much as gentle driving won't get you up the hill, gentle engine braking won't slow you coming down it. So being as gentle driving is necessary for better engine condition when cold, going up and down hills is out of the picture until the car is warm.
Also, driving gently normally is actively heating the engine and lessening its own effect. As demonstrated here, extended engine braking when cold is actually forcing the engine to run at a cold temperature for far longer. It becomes (even for an equal load case) worse over time because the cold running is longer.
posted by Brockles at 10:11 AM on March 8, 2012
High load cases wear more than low load cases, cold engines wear more than hot engines. It's all interrelated but those statements don't at all contradict. The difference in the two situations is that to get any decent engine braking effect you are producing similar load cases to driving up a steep hill and that should be avoided while the engine is cold, too. Just as much as gentle driving won't get you up the hill, gentle engine braking won't slow you coming down it. So being as gentle driving is necessary for better engine condition when cold, going up and down hills is out of the picture until the car is warm.
Also, driving gently normally is actively heating the engine and lessening its own effect. As demonstrated here, extended engine braking when cold is actually forcing the engine to run at a cold temperature for far longer. It becomes (even for an equal load case) worse over time because the cold running is longer.
posted by Brockles at 10:11 AM on March 8, 2012
I have the same car. How many miles?
I find this part a bit concerning: I recently noticed that the engine didn't seem to be warming up during the descent, and only started warming up when I reached the flats and had to start using the gas pedal
To me, that sounds like you're low on coolant (check the reservoir level), or, you've got a failing thermostat. Mine failed at 80k miles with similar symptoms.
Also of note: The temperature gauge in these cars is programmed to show 190° ("normal", right in the middle of the gauge) for a temperature range of about 160-210°F. Don't rely on the dashboard gauge for an accurate temperature reading. For confirmation, use a VAG-COM or another OBD tool to get a proper reading.
posted by bhayes82 at 9:19 AM on March 9, 2012
I find this part a bit concerning: I recently noticed that the engine didn't seem to be warming up during the descent, and only started warming up when I reached the flats and had to start using the gas pedal
To me, that sounds like you're low on coolant (check the reservoir level), or, you've got a failing thermostat. Mine failed at 80k miles with similar symptoms.
Also of note: The temperature gauge in these cars is programmed to show 190° ("normal", right in the middle of the gauge) for a temperature range of about 160-210°F. Don't rely on the dashboard gauge for an accurate temperature reading. For confirmation, use a VAG-COM or another OBD tool to get a proper reading.
posted by bhayes82 at 9:19 AM on March 9, 2012
I find this part a bit concerning
I think the noticing is recent, rather than the behaviour. The car not warming up on engine braking alone is entirely expected behaviour so I really don't think there is any cause for concern. There is unlikely to be an issue with the car.
posted by Brockles at 9:22 AM on March 9, 2012
I think the noticing is recent, rather than the behaviour. The car not warming up on engine braking alone is entirely expected behaviour so I really don't think there is any cause for concern. There is unlikely to be an issue with the car.
posted by Brockles at 9:22 AM on March 9, 2012
Response by poster: I think the [driver] noticing is recent, rather than the [car's] behaviour.
Correct.
posted by wutangclan at 9:25 AM on March 13, 2012
Correct.
posted by wutangclan at 9:25 AM on March 13, 2012
Oh lord, reading some of the theories in this thread is so, so very painful.
posted by davejay at 1:17 AM on March 21, 2012
posted by davejay at 1:17 AM on March 21, 2012
This thread is closed to new comments.
As for the engine temperatures, in my 00" Jetta (manual) I would not always get a correct reading on my engine temperature if the car was on an incline. I don't know if Golfs have the same problem but you might see if the engine gauge goes up once you level-out or once you begin applying the gas.
posted by Revort at 10:10 AM on March 7, 2012