Overheating and misfiring after work done

2006 Jeep Commander V8 196,000 miles

We had a leak in the radiator and took it into a shop to have it replaced. The shop replaced the radiator and we had it back for a day and the heat was cutting in and out. It had also been making some notice upon starting and acceleration, so we thought we would go ahead and have them do the water pump too just in case it was about to go out.

The car came back ten times worse. It overheated, and when it had never done that before even when it was spewing antifreeze from the radiator. So we took it back to the shop. They had it for four days, put a thermostat and temperature sensor in it. They also flushed it. They finally conceded that they don’t know what is wrong with it. We picked it up. It is even worse.

It is misfiring and shaking, on top of overheating. Between the repairs and car rental, we spent all our money, so idk what to do at this point.

There is no sign of a blown head gasket. There is no white smoke and the oil and coolant look fine.

I am not a mechanic, but maybe I can point one in the right direction when we get paid. This is our only car, so we have to keep driving it, even if we have to leave 2 hours early for work :cry:

Could be a head gasket take the radiator cap of when it cold make sure it is full of coolant and start it and watch for bubbles as it warm’s up that would be exhaust gasses leaking from the head gasket. that is what mine did when the head gasket blew.


This sounds to me like a cracked or warped head, allowing leakage between cylinders and/or leakage from one or more cylinders to the water jacket. If the “shop” you brought the vehicle to says they don’t know what’s wrong, they’re just playing coy. They just don’t want to admit the fact that all the work you paid to have done was in vain, because the engine was ruined due to overheating.

Unless you are interested in buying the tools and equipment needed to work on this yourself, and attempting a DIY repair, it sounds like you need to stop throwing good money after bad, and just buy a cheap used car that runs. Sorry to be the bearer of bad news.

1 Like

My husband attempted to drive it to work today and he made it without overheating but now the brake pedal is hard. Wtf did they do to it?

It is possible that there is now an issue with the power brake booster. It should still be possible to stop the vehicle, but it would require a LOT more effort to do so, so this calls for caution.

Whether this could be related to the earlier repairs is difficult to know from afar.

Sounds to me like the first shop has washed their hands of it.

You have 2 options, neither of which are good. 1) Walk away from this vehicle, trade it in on something else. Or, 2) take the vehicle to another shop for a second diagnosis.

Good luck.

We took it to a radiator specialist, supposedly the best in town. They don’t know what is wrong with it either. They don’t even know who to refer us to either. He suggested it could be the PCM, but we just had that replaced in July.

I had an idea…
The car also has an issue with the ignition. In order to start it, you have to pull the fuse and put it back in. Could it be that the fuse box is failing and causing some things to not work like the brakes and maybe the water pump or fan? Would that have anything to do with misfiring if that were the case?

If you just had the radiator replaced, then there’s nothing for a radiator shop to check. It’s brand new.

I’ve found when folks start replacing the “computer” or the PCM, they don’t have any idea what’s wrong with the vehicle. I get that you’ve poured a lot of money into fixing this vehicle. But 15 years old with nearly 200K miles on the engine, and lots of mysterious problems tells me you need to move onto another vehicle.

You can continue pouring money into this one, but you’re still going to have a vehicle past the peak of its useful life. And the problems will only get more frequent and more expensive.


I am a person who likes to save money and keep costs down. In fact, I am as cheap as the day is long. If you look at my posts on this discussion board, you will see that I frequently advise people to keep their current car and repair it, even when just about everyone else here says to junk it and buy something else. Even I am telling you that this Jeep is never going to run properly, and that it has too many problems, which will cost too much to deal with.

Put bluntly, you simply don’t have the time or the money to take it from shop to shop in a futile battle to squeeze more life out of it. You need to focus your limited funds on doing what will result in having a functional vehicle to drive to work–and that is selling this Jeep as-is for whatever you can get, and buying a different used car which runs. Don’t be a fool and continue to throw even more good money after bad.

You could pour thousands of dollars into this Jeep–and still have constant annoying problems, or you could take that money and buy a used 1998-2008 Toyota Corolla and have a reliable car to drive to work. Don’t want this type of car? Then put the money as a down payment, and finance a new vehicle with a factory warranty.

1 Like

You are assuming that a blown head gasket means white smoke out of the exhaust. Not always. It depends upon where the head gasket is blown; IF that is the case. If it’s blown between 2 cylinders with no breach into the water jacket then there will be no smoke.

The overheating could be a symptom of the misfiring/poor running. Should it be assumed the Check Engine Light is on and flashing? Any diagnostic codes set? Or has the shop even done that?


The check engine light came on one time and it read as a misfire. But, it stalls and shakes without a check engine light coming on.

Also, the overheating happened first, and then a day later the misfiring started.

The shop I called a radiator shop specializes in all cooling system parts. They said the head gasket does not appear to be blown. They did not take the engine apart to check for defects because they didn’t feel that was the problem.

So, just an update… We had the Jeep dealership take a look at it. I guess this Jeep is going to become a lawn ornament because we don’t have the title until it is paid off and there is so much wrong with it. They said the O2 sensors are not reading, the catalytic converters are clogged, the Y pipe is broken, and the manifold bolts are broken. I found all those parts pretty cheap online, but I am worried that there is something underlying all this that won’t be fixed by replacing those parts. I guess what really bothers me is that the sensors aren’t reading. If the mechanic said they were bad, that would be one thing, but not reading at all? Maybe an electrical issue? I don’t want to give up, but I have a bad feeling that replacing the sensors and the converters isn’t going to fix the problem.

While not a good situation you can trade in your current vehicle . The balance will be rolled over into the loan with the next vehicle . Sometimes one just has to do things that are not really what they want . You will be even more upside down on the loan then you are now. Only you can make that decision .

This vehicle has some serious problems. You can continue pouring money into “maybe” fixing the problems… or you can trade it in on something probably better and more reliable.

This situation is not going to get any better or cheaper. You’re going to have to choose the lesser of two evils.

Has anyone checked to see if a timing chain has jumped time?