Help me understand what happened to my car's engine.
December 23, 2014 2:04 PM   Subscribe

Why did my car engine suddenly go bad?

Background information: I have had a 1993 Honda del Sol for about two years now. It's been a great car with minimal problems. The past year I haven't used it all that much, since I live in a small university town and take the transit to campus most of the time. However, the "Check Engine" light has been on for a couple of months; I'm ashamed to say that I ignored it since there hasn't been any obvious problem other than this: occasionally there would be trouble getting it to start when already warmed up. (I'm guessing this was some sort of fuel problem.)

I was driving the car down the interstate the other day. Everything was fine until all of a sudden something went horribly wrong--it felt as though I had a tire blow out or something. The car was shaking, moaning, knocking, white smoke was coming from the engine. I coasted over to the side of the road while the engine died completely. I had to get it towed to the mechanic, who says it is indeed an internal engine problem. An awful knocking noise comes from the engine whenever we try to start it up. Okay, so I understand something went wrong with the engine, but what? Why did it happen so suddenly? What caused something like this to happen? Any helpful diagnostic insight would be much appreciated.
posted by fignewton to Technology (21 answers total) 2 users marked this as a favorite
Did you ask your mechanic? He's really the person in the best position to answer this question.

It's probably not this, but: a Del Sol is a Civic. Civics at least used to have a timing belt, and bad, bad things would happen if this belt failed at highway speeds, which is why people used to have those replaced religiously at 100K miles.

I say probably not because that wouldn't cause the check engine light to come on pre-failure. But maybe it's two unrelated issues.
posted by selfnoise at 2:07 PM on December 23, 2014 [3 favorites]

If you were tooling along, happy as a clam and then suddenly hear a KER-CHUNK! It may have thrown a rod. You have to tear up a car pretty badly to have that happen. But ignoring a Check Engine light for two months might qualify. Typically it's lack of oil and/or running the car hot. I've been in two cars that have thrown rods...I'm not ignoring ANYTHING on my vehicle.

If you've thrown a rod, it's an engine replacement thing. Say a brocha and commend your car to the car afterlife.
posted by Ruthless Bunny at 2:13 PM on December 23, 2014 [2 favorites]

Any helpful diagnostic insight would be much appreciated.

You will not get any here, just a wild selection of guesses (mine included). Internal engine failure like that is impossible to diagnose with the information provided and without looking at the car itself any diagnostic insight is entirely guesswork. But it is likely that a connection rod (between the piston and the crankshaft) has broken or bent. Possibly as a result of the timing belt snapping (so the top half of the engine doesn't rotate at the same time as the bottom half and stuff hits stuff). That would match with the vibration issues and the smoke. Another alternative is that a valve dropped into the piston and the engine was damaged (possibly bent connecting rod) when this happened. But.. it's impossible to say other than your engine is pooched. Very definitely severely pooched.

But - to at least roughly point the right direction - Did you check the oil recently? Did the car overheat? Has the oil been changed recently? When was the timing belt last changed? Any symptoms the car gave you before? I mean, it's pointless to investigate too much, because the engine is pooched, but you may learn how to avoid this in future, I guess.

I suspect the check engine light is unrelated, but it is random as to whether that is the case. If it was triggered by a timing issue (as the timing belt stretched) then it was a symptom. There is no way you can assume a check engine light is a fuel issue (or anything else) without significantly more information and diagnosis, which is why check engine lights are stupid (don't start me off on that one....).
posted by Brockles at 2:20 PM on December 23, 2014 [7 favorites]

The Del Sol had an interference engine, which means that the pistons can occupy the same physical space as the valves, unless the timing of them occupying that space is timed right. Timing that is the job of the timing belt. If the timing belt fails, both the valves and the pistons can occupy the same space. And completely kill each other, which is bad, since you need both. When the belt goes, it's a big noise.

If that's what it was, your engine is never going to work again (and even if it wasn't, things aren't sounding good).

Good luck.
posted by Admiral Haddock at 2:35 PM on December 23, 2014 [5 favorites]

The CEL is an indicator that the self-diagnosis systems in your car have detected something wrong. Whenever you see this light, you should at the very least use a scan tool to read the error code, or take it to a mechanic to get it diagnosed. The reasons for a CEL can be dumb (loose gas cap), indicate the need for minor maintenance (the last CEL I saw indicated I needed a couple new ignition coils), or point at something Really Bad. You definitely shouldn't ignore it and hope it will go away.

Your mechanic will be able to tell you what happened to your engine. Whether or not your two-month old CEL is related may be impossible to determine now, as whatever error code you would have seen if you had gotten it diagnosed then has likely been overwritten by whatever happened. It *is* entirely possible, though, that having the CEL diagnosed (and addressed) when you saw it instead of letting it linger would have prevented catastrophic failure. Regardless, from your description of what happened, your engine is almost certainly dead.
posted by strangecargo at 2:43 PM on December 23, 2014 [2 favorites]

Response by poster: Yes, strangecargo, I have learned my lesson.

Thanks for all the feedback, everyone.
posted by fignewton at 2:45 PM on December 23, 2014

We can only speculate - you'll have to ask your mechanic for an actual diagnosis. The other posters have some good info (although, the car won't start if the timing belt has failed).

I had a similar thing happen to one of my cars once, and what had happened is that the piston shaft broke and broke through the cylinder wall. This released hot coolant into the oil pan, while simultaneously unbalancing the engine. That made it really run like shit, and blow lots of white smoke out the exhaust. It knocked horribly from where the broken shaft slapped around in the cavity. I was surprised it ran for a long as it did - when I got the engine apart, it looked like a grenade had gone off in there.

In your case, it sounds like the best possible outcome is a blown gasket or valve, or a cracked head. The worst is a complete engine replacement.
posted by Pogo_Fuzzybutt at 2:50 PM on December 23, 2014

FYI: '93 del Sol engine

My mom had a del Sol for a while. Worst. Blind spot. Ever.
posted by spikeleemajortomdickandharryconnickjrmints at 2:55 PM on December 23, 2014

The knocking was likely valves hitting the pistons, conrods hitting the cylinder walls, or run bearings rattling. Possibly all three. Any one is a death sentence for the engine.

Why they did this is not a relevant question at this time, but something to ponder in the future, to stimulate your interest in regular preventative maintenance, and prompt attention to problems as they appear. It is only a machine, but it does require a certain amount of TLC.

It may be repairable, but probably not an economic proposition, it may be best to start looking for a new car, or a decent engine from a wreckers.
posted by GeeEmm at 3:05 PM on December 23, 2014

In all likelihood the timing belt broke and the tops of the pistons and the valves tried to occupy the same space at the same time. Best case scenario, new or rebuilt head if there was no piston damage but that's unlikely.

Long blocks and used engines both look like about $1200 - $1500 plus the labor to install unless you're handy and have a well equipped tool box.
posted by Grumpy old geek at 3:37 PM on December 23, 2014

Everyone has covered why the problem can't be diagnosed here, but likely this was a problem that was building over time where some piece was gradually getting weaker and weaker, until it finally snapped and sent tens to hundreds of precision of engine parts that operate on tolerances of thousandths of an inch out of whack.

Sometimes its the unlucky lottery and the broken part had an undetected manufacturing defect, or its a wear part, like a timing belt, that needs to be replaced over a certain time frame.
posted by hwyengr at 3:42 PM on December 23, 2014

The three rules of owning most newer cars:
1. Check-engine lights MUST be dealt with right away.
2. Timing belts MUST be replaced on schedule if you have an interference engine (the 93 Del Sol is one).
3. Oil and oil filters MUST be changed in accordance with the schedule in the owners manual. Transmission and coolant SHOULD be checked/changed as close to the schedule as possible.

It's been my experience that as long as you do #1 through #3, you can probably get away with neglecting things until something goes wrong. It's sounding like #1 was definitely an issue, and from the description of what happened, my money is on #2.
posted by crapmatic at 4:24 PM on December 23, 2014 [2 favorites]

That would be an exact description of what you'd experience if the timing chain/belt slipped. So that's certainly one way.
posted by humboldt32 at 5:12 PM on December 23, 2014 [1 favorite]

Okay, so I understand something went wrong with the engine, but what? Why did it happen so suddenly?

But it wasn't suddenly. The check engine light was on for months!
posted by DarlingBri at 5:43 PM on December 23, 2014 [3 favorites]

When the timing belt broke on my Ford, the result was that engine wouldnt start or run. It was fixed by a regular garage in a day. When it happened to my father's Alfa, it was catastrophic as described above. It was repaired and Dad had a bent valve to decorate his desk.

With my first car, I did not understand about oil changes. Eventually, bad things happened to the valves, and I had a complete engine overhaul.

It's hard to imagine that a 20 year old car isn't toast.
posted by SemiSalt at 5:55 PM on December 23, 2014

Something similar to me happened when the timing belt broke on my engine. Do you have a manual transmission? If so, this would be consistent with a total engine breakdown. It would also explain severe knocking, as well, when you try to run the engine. As noted above, if the timing is off, stuff gets bent out of shape in a pretty severe way.
posted by SpacemanStix at 9:02 PM on December 23, 2014

You don't say how many miles it has on it, but a 1993 car is likely into the 'change the timing belt' mileage range. So if you or previous owners never had that done, it is certainly a very possible scenario to have the timing belt break suddenly.
posted by flug at 11:26 PM on December 23, 2014 [1 favorite]

Do you have a manual transmission? If so, this would be consistent with a total engine breakdown.

The transmission is entirely irrelevant to the fault, symptoms or cause.
posted by Brockles at 11:16 AM on December 24, 2014 [1 favorite]

You should really ask the mechanic what happened and then you can take their response and post it here to get it decoded into plain English, if you like. But all we can really do is speculate. Bottom line is that it's probably nothing good.

The check engine light could have been on for any number of related or unrelated reasons. It could be that you were running without oil or something, and you threw a rod. It could also be that the timing belt was stretching, causing some sort of timing error code to turn on the CE light, and then the belt snapped—depending on the design of engine possibly taking your valves and cams and a bunch of other stuff to automotive heaven along with it. Or the CE light could have just been coincidental, caused by a hundred other things that can happen in an older car. Impossible to say, really.

It is unlikely that it is worth rebuilding an engine in a 1993 Civic if something really catastrophic happened, which it sounds like it did. Depends on local labor rates, though. In my area the car would be scrap because the time to even swap for a crate engine would be more than the chassis is worth. But in some parts of the country where labor rates are more reasonable, it might be worth it. That's a whole separate question which requires the diagnosis from the mechanic of exactly what happened first.
posted by Kadin2048 at 12:30 PM on December 24, 2014

As I recall, the CEL on a civic that old is probably mostly emissions. I'd wager that the fault is coincidental. It does sound catastrophic.
posted by wotsac at 12:41 PM on December 24, 2014

In my '97 VTEC the check engine light also came on when the engine oil got dangerously low, which was when I learned that it had started burning oil. In my case the car refused to start one morning, I got a stern talking-to by the mechanic about checking my oil (which I had done reliably up until the point I didn't), and I started putting the special "old car" Castrol in it.

I also paid a stupidity tax when I got the timing belt replaced, forgot about it, moved, went to a different mechanic, and got the timing belt replaced again.

If you never had the timing belt replaced that seems the likely culprit, followed by running the engine dry and seizing it up.
posted by fedward at 3:47 PM on December 24, 2014

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