So I just got my car back from getting a new ECM, waterpump, and opti, as well as a new a/c compressor, and about 5 miles down the road it starts overheating. Not pegging all the way to the right side of the red, but sitting exactly in the middle of red. I pull off the highway and take it into another shop (one that I've worked with before), and they tell me that exhaust gases are leaking into the coolant, and that it would be just as expensive to replace the engine as it would to replace the head gaskets. Now I wouldn't think this all too suspicious, but I had a Durango towed into the same shop last year that needed the engine replaced as well. Do I just have really bad luck, or is this shop not as trustworthy as I thought? There was no white smoke, no loss of power, just overheating. Basically, is it possible that a bad head gasket could cause overheating like this due to exhaust gasses? And if so, could someone give me a link to a guide for replacing the gaskets? I know I saw one before many years ago, but it's not on Shoebox's site...

Thanks

 

They might not have bled the system right. Did your fans come on. Was the radiator still full. Unless you had a giant plum of white smoke trailing you while driving, I would look at the fans and bleeding the system first. You can't just fill the radiator and assume that it's full. A air bubble from not bleeding the system will cause it to over heat.

 

Check the coolant level in the radiator, not the overflow.

 

Where do they get the idea that it would cost the same to replace the engine as it would the head gasket? That's rediculous. Even factoring in the machine work for the heads its still not even close. A competent mechanic should be able to pull the heads off and reinstall them in one day. I would take my business elsewhere, actually I would do it myself. I bought my car with a blown head gasket and for under 1500.00 got it back together myself and that included 900.00 in head work and a new cam!

 

i agree. that is absurd to think that it would be the same to replace a head gasket and the entire engine. you could do just like the guy posting above me and still be cheaper than a new engine. if you have any kind of mechanical knowledge and access to tools and a building to work in you could replace the head gaskets yourself. trust me, its not that hard. just my honest opinion tho.

 

make sure there is nothing in front of the radiator like a plastic bag

 

Air bubble was my first thought, so I bled the coolant lines after it started overheating and it didn't fix it, so I know it wasn't that. I didn't check the fans yet, and as the engine was hot didn't want to open the pressure cap. Their claim that it's the same amount was basically because of labor to pull the engine (don't see why this would be necessary personally), but that was what made me decide to get it home and do it myself. Plus I want the original engine staying in the car. I do know that the air dam was not on the car, as it was sitting in my garage at the time, but I'm fairly certain that wouldn't be enough to make it overheat.

My plan right now is to go through and check anything I can, and if I rule out everything else I'll replace the head gaskets. A couple questions concerning that:

1. Can I just remove the heads without disassembling them beyond removing the valve covers (leaving rockers, lifter, valves in place)?

2. Are Impala gaskets really that much of an improvement for an internally-stock engine, or should I stick with Camaro's?

3. Are any special tools required to swtich the head gaskets?

4. Is there a way to tell what caused the gasket to blow if it is that, and how long it's been broken?

5. How to I check to make sure the heads haven't been damaged/warped?

 

The missing air dam can and will cause overheating. Put it back on and see if it happens again.

 

You have a lot more options before pulling the heads. Does it get too hot when sitting or driving? If it gets too hot while sitting make sure the fans are coming on. If it gets hot while driving it's most likely the missing air dam. Is the water pump working? Check this by removing the radiator cap while it's cool, make sure it's full and start it up and see if coolant is flowing thru the radiator. Radiator could be clogged up as well. Has it been flushed lately? Thermostat working? To check this take it out put it in a pan of water on the stove and heat the water up, you probably have a stock one and it should open at approximately 180 - 190 degrees. I would try these before pulling the heads.

 

thanks for all the help, I'll try it all when I get back home in a week, but I definitely like having options. BTW, assuming it is what they said, how would they be able to test for that...basically, can I repeat the same test if nothing else works to reassure myself before pulling the heads?

 

if its a head gasket you will know it from the smoke but more importantly, you'll be losing coolant. The head gasket should be the last resort. I know you said you bled the system, but do it again; it can be tricky and time consuming sometimes!

ps- does the air dam really make that much difference??

 

Took me about a week working on the car for 3-4 hours a night to do my headgasket. It wasnt bad..The worst part was getting the exhaust manifolds off, as well as breaking the headbolts since my breakerbar was tiny. You could easily do the whole job for under $300 if you do it yourself.

 

Yeah, it scoops in the air, otherwise it would funnel around the car. I suppose you could drive highway with your fans on but that seems dumb.

 

At my shop we have a few very good ways to check for a head gasket failure. First there is an exhaust gas analyzer which can detect exhaust gasses in the coolant and we also have strips that can be put in the coolant and will let us know the same. I suggest you bring it to a shop who can do this first. Also, a pressure test on the coolant system couldn't hurt...it wont always identify a blown head gasket but you may find a leak elsewhere that is your cause for overheating.

You may as well check every other option before dropping cash on a head gasket swap though. A bleed down or compression test couldn't hurt.

If it comes down to being a head gasket, I agree that it shouldn't cost near as much as replacing the motor. I am a B body guy so it's a little easier to work in the engine bay but I assume on the F bodies it is also possible to remove a head without pulling the motor. Removing a head on our motors really isn't a HUGE job....not as bad as a lot of other cars anyway.

 

Okay, so it's been almost a year since this problem showed up, and I'm more confused now than ever...

As usual, life got it the way, so I haven't really done much with the car other than store it for the past year. I've started it about once a month and let it run for 10-15 minutes just to keep everything flowing, but other than that haven't addressed the overheating problem.

Today I went out and started it and let it run for about half an hour, drove it for maybe 2-3 miles. The temp gauge never moved off of 100. I know from this that the gauge is obviously broken, but the engine did warm up pretty well, just not the blazing heat of 260+ degrees. After it was hot, the A/C was still ice cold as well. Wouldn't this signify that the overheating problem is not a problem anymore?

Granted, the overheating only happened the one time, right after I got it back from a whole array of repairs (see first post for list). Is it possible that the overheating last year was just a temporary result of those repairs, and that the engine had to work something through it? Like I said, I'm blind on this as I've never had overheating problems before, but if it's ok now then I'd love to be able to start driving her again.

Any help greatly appreciated...