Audi A6 problems
July 25, 2012 5:02 PM Subscribe
Audi A6 car coolant/radiator troubles...
Asking for a friend:
"Here's the story. The old car we got from my brother-in-law (1996 Audi A6) is a bit of a dud. The first week I drove it to work it had an issue where the coolant tank overflowed...basically the pressure of the tank caused the coolant to steam out of the hood and then boil over.
I took it to this mechanic who he recommended having used for over a decade on this car as a great and fair mechanic. He confidently identified the problem as a radiator fan (not turning on when it should, causing overheating) and thermoswitch. He replaced both of those along with a frayed belt and changed the coolant. Cost was around 650$.
Drove the car home that night no problems. On the way to work I have the exact same problem. Obviously it hasn't been fixed.
I bring the car back. He claims that he had fixed the issues and that my car had come in overheating. I definitely remember telling him that the temp gauge hadn't been overheating. We go out and "recreate" the incident, where the coolant overflows. He then says its possibly due to a malfunctioning cap. He sells me one for 10$.
I drive the car home in a panic that nothing has been fixed. Luckily I made it.
I'm planning on driving it around this weekend to see if the problem happens again. Can I be confident that it's fixed? If not, how do you recommend getting my money back? And even if it was fixed, why did I pay for all these repairs if it was just a stupid cap?"
Asking for a friend:
"Here's the story. The old car we got from my brother-in-law (1996 Audi A6) is a bit of a dud. The first week I drove it to work it had an issue where the coolant tank overflowed...basically the pressure of the tank caused the coolant to steam out of the hood and then boil over.
I took it to this mechanic who he recommended having used for over a decade on this car as a great and fair mechanic. He confidently identified the problem as a radiator fan (not turning on when it should, causing overheating) and thermoswitch. He replaced both of those along with a frayed belt and changed the coolant. Cost was around 650$.
Drove the car home that night no problems. On the way to work I have the exact same problem. Obviously it hasn't been fixed.
I bring the car back. He claims that he had fixed the issues and that my car had come in overheating. I definitely remember telling him that the temp gauge hadn't been overheating. We go out and "recreate" the incident, where the coolant overflows. He then says its possibly due to a malfunctioning cap. He sells me one for 10$.
I drive the car home in a panic that nothing has been fixed. Luckily I made it.
I'm planning on driving it around this weekend to see if the problem happens again. Can I be confident that it's fixed? If not, how do you recommend getting my money back? And even if it was fixed, why did I pay for all these repairs if it was just a stupid cap?"
I had a Honda Civic (1980s vintage) that did something similar. The fan wouldn't turn on, so it overheated. I checked that the fan worked and replaced the switch. The fan still didn't turn on, and it still overheated.
The actual problem turned out to be that the radiator was clogged. The radiator was clogged because there was a blown head gasket blowing combustion by-products into the coolant. This also caused excess heat and pressure in the radiator, blowing the coolant out through the cap into the reserve tank and boiling the coolant.
The proper thing to do, I think, is have a (possibly different) mechanic do a cylinder pressure and leakdown test to make sure you don't have a blown head gasket or other serious mechanical problems.
posted by leapfrog at 10:58 AM on July 26, 2012
The actual problem turned out to be that the radiator was clogged. The radiator was clogged because there was a blown head gasket blowing combustion by-products into the coolant. This also caused excess heat and pressure in the radiator, blowing the coolant out through the cap into the reserve tank and boiling the coolant.
The proper thing to do, I think, is have a (possibly different) mechanic do a cylinder pressure and leakdown test to make sure you don't have a blown head gasket or other serious mechanical problems.
posted by leapfrog at 10:58 AM on July 26, 2012
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With a defective cap, the water will expand, leech out the cap/through the overflow and the water volume will get smaller. It will become progressively less able to cool the system and make itself worse until the volume is enough that the system boils. One of my race cars did exactly that last year.
I'd drive it with a jug of water in the boot. If it does it again, you have a serious internal issue, but it is quite likely that has fixed it. If the cap didn't fix it, then I don't think there is much you can do to limit any damage.
If not, how do you recommend getting my money back?
It sounds like he did a less than thorough diagnosis, but with the frayed belt being obviously faulty and a coolant flush inevitable when you've lost most of it, you'd have to prove that the fan and switch were also not faulty. It is possible the cap is the end result, rather than the only fault. Without testing the components you kind of have no way to know. If your mechanic is a 10 year reliable mech, then this may just be an honest mistake and he may well look after you on your next visit if he feels he should have caught it. Not sure you have much recourse otherwise.
posted by Brockles at 5:22 PM on July 25, 2012