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New Timing Belt, now coolant fouled plugs?

2004 Chysler Sebring
2.4L 4 Cyl
130k miles

Hi guys. Thanks up front for taking questions. I just had a new timing belt kit put on my Sebring after the belt snapped out on the road. My engine is non-interference (luckily). Trouble is, the day I got it back, it idles rough and it stalls when I slow down below 1k rpm (slowing for traffic lights or turning into driveways). I take it back in and they tell me I have coolant fouled plugs because “coolant got blown in there when the belt snapped” and something about the throttle body being fouled. They’re quoting me for $450 for new plugs, ignition wires, new brake pads and other work. Should they have noticed the ignition problems when they were taking it apart for the time belt? They told me when I picked it up the first time that they had test driven it and everything was fine. I don’t see how they could have overlooked a car that stalls at every turn and red light. It also looks as though coolant on plugs may be caused by a blown head gasket. Are these guys stringing me along a series of “newly discovered” repairs?

If your 2.4L engine is the single overhead cam design, it’s an interference engine.


It’s DOHC. Everything I’ve read about my engine and what the shop told me is that it’s a non-interference design. Thank you.

If you ran it until the timing belt snapped, you probably have not done much cooling system or other maintenance edither. At 130,000 you should be ready for your second timeing beltrepalcement. Cooling system should have been flusged and coolant replaced at 50,000, at 100,000 and next 150,000 miles at least.

Please tell us exactly what maitenance this vehicle has recieved and then we can advise whether the items identified by the shop make sense. If you have not done any of the items I mentioned, I’m surprised the car ran at all.

P.S. Blown head gaskets are very common on these engines.


I’ve done many timing belt jobs over the years

It’s not necessary to remove the spark plugs to do the timing belt

I think you shouln’t have any more work done by these people except to confirm that the timing belt marks still line up and the belt tension is set correctly. The answers they gave you are smoke to hide a bad job.

These engines “suck” to get the camshafts lined up properly and I would bet that they have the timing belt misinstalled. But that’s just a guess from an internet forum. The only way to confirm this is to disassemble and inspect.

But, there’s no way that a snapped t-belt could cause coolant to foul the spark plugs or make the throttle body dirty. Well, I suppose it might be possible if the engine suffered massive internal damage when the belt broke, but it sounds like that’s not the case.

If the coolant on the plugs is from a head gasket failure I would think you would have had overheating issues before.

4 plugs and wires is ALL you need to make motor run ok. If that is only motor issue. U just paid the shop a lot more for timing belt job and now they want to hose u on plugs /wires? Why are they jerking u around on brakes? Get the darn motor running first

I can’t say definitively whether or not the engine is an interference fit or not but several parts sources show it as one.

Maybe this substance on the spark plugs is not coolant at all and the plugs are wet due to incomplete combustion; either due to bent valves in an interference engine or because one or both camshafts are not timed correctly if it’s a free-wheeler.
There’s also the slim possibility of valve to valve contact instead of valve to piston.

Is there any white smoke out of the tailpipe? I would think that if the plugs are being saturated with engine coolant then it should look like a fog machine at a rock concert.

Was the engine running fine when you first picked the car up or did this rough running occur later?

Even if a non-interference engine, if the timing belt breaks it could still do serious internal engine damage. Especially if it occurred at freeway speeds. It seems like there could be a combination of events that would results in higher than normal compression pressures for example if the valves and pistons got out of sink. And something like this could damage the exhaust system, the cat, or the intake manifold or throttle body too, from the unusual pressures that would result. Head gasket damage goes without saying.

So what to do? First of all check the computer DTC codes. Next, I think I’d be inclined to remove the spark plugs and let it sit for several days, let everything inside the cylinder evaporate out the spark plug holes. And let the spark plugs dry off sitting on the work bench. If the spark plugs look ok after that and are properly gapped, I’d just re-install them. If that didn’t fix the problem, I’d do a compression test. Still a no go? Remove the throttle body for a look-see and proper cleaning.

After that, you’ll need to find a shop with a Chrysler scan reader and some drivability expertise. You may be looking at a partial rebuild job (hopefully just the head) or even a new engine.

Thanks for the input, everybody. I’ve taken the car back from the shop. To answer a few questions, I was slowing down for a red light when the belt snapped, no more than 40mph. I haven’t experienced any overheating problems in the time that I have owned the car. In the 80k mileage that I have put on the car the cooling system has not been flushed. I’ve been fairly regular on oil changes (no black sludge etc). The 2.4L engine for my car comes in a SOHC (Interference) and DOHC (Non-interference). I definitely have the DOHC non-interference engine. I have no tail-pipe smoke and do not smell any coolant. The shop also elaborated on the coolant issue saying that the water pump must have overheated when the belt snapped, increasing coolant pressure and causing coolant to spray. I’m not sure how that makes sense as the engine immediately ceased activity when it lost the T belt.

Oddly, the car seems to be improving as I drive it. The first day I would stall at every red light or turn. Every day since I would estimate the stalls have reduced by half in frequency, though idle is still not smooth.

I’ll be back in my home town for Xmas, so I will get some free time to swap the sparks plugs and wires. I will do this whether they are actually fouled or not (it’s about time) and will try to clean out the throttle body. I may check the airflow sensor to see if it is damaged or dirty as well.

A poor idle and fouling plugs are symptoms of an out of time engine. Check this out

From what I see, the 2.4L DOHC, it is indeed free-wheeling as far as piston to valve clearance; however valve to valve interference is another matter. If the timing belt breaks, allowing the two camshafts to turn independent of each other, the valves can knock into each other. A compression test would go a long way in determining if this is a problem in this case.

“The shop also elaborated on the coolant issue saying that the water pump must have overheated when the belt snapped, increasing coolant pressure and causing coolant to spray.”

Holy cow - is all I can say. If someone said that to you with a straight face then there’s no telling what happened when they did the work. I’m with asemaster that my very first guess would be that it wasn’t timed properly when the belt was done.

The water pump is driven by the timing belt so if the belt snaps the engine is going to quit running then and there.

Just some food for thought. The water pump is driven by friction from the back side of the timing belt. What if the pump was seized or trying to seize and the T-belt was slipping on the pulley?
That could lead to overheating followed soon after by a frayed T-belt giving up.

That’s all theory but one would hope that a shop should note the water pump condition and consider the possibility of overheating if that happened to be the case.
Of course this all predicated on the coolant on the plugs scenario and the assumption that the camshaft timing is correct.

If it is a non-interference engine no damage will result if the belt breaks (unless you stop in front of a train or traffic) . Cylinder pressures are highest just after the plug has fired and the piston is passing top dead center on the compression stroke and going into the power stroke. Nothing that happen after the belt breaks can exceed that pressure.

I’m betting the shop did not align the marks properly on the timing belt or tension it correctly.

I’ll be getting a Chilton manual to see if I can check T belt alignment myself. If I think it’s off then I’ll take it to a dealer and get their opinion. The original work is supposedly warrantied for two years. Do you guys think I can get the first shop to cut me a check if I have the dealer correct the timing, or will they demand that it be done in their shop?

I would verify myself that the timing is off and then have the same shop fix it. That way they see for themselves and can’t deny responsibility.

I would agree with the camshaft timing being off IF the car did not overheat prior to the belt snapping and IF the original water pump was not flawed in some way.