1998 Sunfire Overheating

Alright....here goes. I don't think I've ever been so frustrated with anything in my life! ARGH!

I have a 1998 Pontiac Sunfire SE. 2.2L. The current milage is 106K. The only three major problems that I had ever encountered were replacing the water pump at about 70K, replacing the alternator at 90K, and rebuilding the transmission at 100K. Other than that...has always run great.

About a month ago, my car began to run hot. I first had it checked out at a local, well-trusted radiator shop to check for anything obvious. Turns out, it was low on coolant. The filled the coolant up to normal levels, and the car ran fine for about a week. Soon after, the temp would go up to the red zone, then come back down. I watched my coolant level for a few days, and yes, it was again running low. Also, I checked for otehr things at the advice of friends, like checking the oil to see if any coolant or water had leaked into it, and nothing had...the oil was fine. There was also no noticable smoke or liquid coming from my exhaust. Both signs of a blown head gasket, right?

On Sunday of that week, my car cut off on me, I assume from over-heating. It started back up after about 5 minutes of waiting. The enxt day, I took the car to a rapair shop, and ironically, it cuts off as I'm pulling in. Two days later, they call to tell me I had a blown head gasket. Costs for the repair...approx. $700.

I spoke with a family friend who claims to be a master mechanic. He found a replacement engine for me with 30K miles on it for $450. That weekend, the two of us replaced the engine. After about 16 hours of work, we get the engines changed out and everything back together. During this, we replaced the water pump, heater and radiator hoses, and thermostat. Also filled it up with new coolant. Ten minutes after cranking the car up, it starts to over-heat. The next day, we flush out the radiator and replace the temp. sensor. Afterwards, the car runs great....let sit for about an hour...no over-heating. The car runs perfectly....for 5 days.

So up to this point, the only thing that hadn't been fully replaced was the radiator. I bought a new radiator ($164) and had it put in ($120). They told me it was still running hot. Low and behold, they were right. Their words were "Looks like you've got a blown head gasket."

ARGH!!!!!!!

Last night, on the way home from a very quick trip, the temp. gauge spiked, and suddenly dropped, almost as if the car had been cut off (but it was still running). Then, the check engine light came on. Mind you, this is the first time I'd ever seen the check engine light come on since the initial water pump outage.

I'm no car expert...I don't claim to be although changing engines will make you learn a thing or two. Now I'm really frustrated. I'm going to take the car to the dealer to have them look at and/or fix the problem once and for all. I should have had the original problem I was told, the blown head gasket, fixed by the pros. At least then they'd be responsible for anything that didn't get fixed.

Can anyone please offer me any advice as to what could still be causing my over-heating???? Today, for example, not even 5 minutes into driving my car, and it starts to run hot. I did notice, however, that when I am idle, the temp goes DOWN. My coolant level is fine, and so is my oil. No signs of head gasket problems, unless I don't know what to really look for.

Any advice what so ever would be GREATLY appreciated!

Thanks! Trey

Reply to
treyd
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Could be anything in a used engine.

Reply to
hyundaitech

I hate to say it, but this was your first mistake. A 2.2 engine is quite a solid little engine, and "if" the original had a blown head gasket, you would have been further ahead to deal with a "known" engine. Now you have to start all over and who knows what you have. A used engine is "always" a crap shoot. Doesn't mean it's not a good idea at times, (I've installed plenty of good used engines), but you only use them when the other engine is too far gone to fix. A cylinder head gasket on just about any engine is never "too far gone".

Ian

Reply to
shiden_Kai

Thanks Ian.

I guess I felt that since I trusted the person helping me, and he trusted the source that he received the engine from, that everything would work out perfectly. I hate to think that the engine I got that was put in also had a blown head gasket, but what are the odds of the EXACT same things happening with two different engines? I mean, I know it could be a number of things, but all the critical components have been replaced (thermostat, radiator, water pump, hoses, sensors). What am I missing? Should I be looking for any kind of signs?

One interesting note...earlier, I was looking at the engine and I noticed a sensor located right below the coolant resivoir. I tapped it and made sure it was snug, and suddenly, my check engine light was no longer on. I know that this is the coolant level sensor, and really should only tell me if I have a low coolant level, right?

Thanks, Trey

Reply to
treyd

Pretty high, which makes me think that you may have some other problem. It's too difficult to try and diagnose it over the internet based on what you've thrown out. While it is common for head gasket failures on these engines, it's not nearly as common for the failure to be one where the coolant enters the cylinders. Usually the head gasket splits at the left rear of the block and leaks externally.

Yes, as far as I know, that should have no relationship to the "check engine" light. You aren't confusing the two are you? It appears that you do know the difference. First thing I would do is to check and see what the check engine light was responding to. In other words, go see what the history code is.

Ian

Reply to
shiden_Kai

I'm not going to pretend to know much here. I just have a thought I'll share that may or may not lead to help.

Could the computer or a circuit directly related to the computer be shut down or faulty? As in the computer is not responding to the rising heat and therefore not doing anything to correct it?

Just a thought

Tony

Reply to
Tony V.

Oh, and also if the computer or sensor related to engine timing is faulty.

I guess it's time to do as Ian says, get the code(s).

Tony

Reply to
Tony V.

Thanks for the ideas. I suppose I just need to go to the dealership service center to have them check the computer? Someone also mentioned to me that some Autozone stores can do this - would this be better than the dealership?

I got another suggestion from someone regarding something I hadn't even thought about - the heater core. Would this play a big part (if something were wrong) in why the car would over-heat? Is there anything I can do myself to check for problems with the heater core?

Thanks to everyone for the advice!

Trey

Reply to
treyd

First thing you MUST do is make sure there is NO AIR trapped in the system. Can some times be more difficult to accomplish than you might think. If there is air in the cooling system of a Sunfire it WILL overheat. Open the highet point in the cooling system to let the bubbles out. On a particular stubborn old renault, I resorted to putting the front end on the hoist ant the rear eand on the ground, then loosening the top rad hose. Have seen it done using a tow truck too.

Reply to
nospam.clare.nce

I don't think that the heater core will have much to do with the problem. But I did just realize what year your vehicle is. In that year, the 2.2 engine is impossible to bleed properly unless you open the bleed screw that is located in a heater pipe ( I believe it's located right under the coil packs at the rear of the cylinder head). You must open that bleed screw and keep filling the overflow bottle until clear fluid with no air comes out of that bleed screw.

Perhaps you have already done this, but if not, I'd do that before I did anything else.

Ian

Reply to
shiden_Kai

I have a 98 Sunfire also. A few weeks ago my car started having similar problems. I had a new pump and thermostat put in 3 months ago so I knew that wasnt the problem, so I checked out the electrical part of the cooling system. Heres a quick explaination of how it works. The "temperature sending unit" tells the computer (PCM) how hot the car is, when it reaches a certain temp, the computer turns on the "Fan relay" which in turn starts the fan. Everything checked out fine except the signal coming from my cars computer (PCM) to the relay. The signal is to week to turn the the fan on... My guess is my PCM is going bad (acting eradically) so Im going to replace it tomorrow, hopefully that will do the trick. Didi you get your car fixed?

Best of luck Will

Reply to
WillGWM

I have a 98 Sunfire also. A few weeks ago my car started having similar problems. I had a new pump and thermostat put in 3 months ago so I knew that wasnt the problem, so I checked out the electrical part of the cooling system. Heres a quick explaination of how it works. The "temperature sending unit" tells the computer (PCM) how hot the car is, when it reaches a certain temp, the computer turns on the "Fan relay" which in turn starts the fan. Everything checked out fine except the signal coming from my cars computer (PCM) to the relay. The signal is to week to turn the the fan on... My guess is my PCM is going bad (acting eradically) so Im going to replace it tomorrow, hopefully that will do the trick. Didi you get your car fixed?

Best of luck Will

Reply to
WillGWM

First, you didn't happen to use the original engine's thermostat in the "new" engine, did you? Check the thermostat. Second, check the radiator cap. Yeah, simple, bat-stuff things, but maybe....

Most likely, to echo what WillGVM (or similar, in a follow-up to subsequent posts) has said, make sure that the cooling fans are coming on. The Sunfires (of the years including your's) have horrible air flow naturally over the radiator (that closed front nose); cooling fans are necessary to cause a negative-pressure situation behind the radiator, ergo a tendency for air around the vehicle to pass over the cooling fins of the radiator. If the fans (electric) aren't coming on this could be a huge source (if not *the* source of your problem). Try this, let the car warm up and see if, when it starts to trend towards "hot" if one or both (I think they have two fans) fans don't come on. Also, run the A/C; most cars run both fans, regardless of temp, when the A/C is running (at least, that's how my mind remembers it). When I had a similar problem (both cooling fans not running) in my 1990 'vette the problem turned out to be simply a corroded ground wire contact; unscrew, scrap, screw, done (after much troubleshooting).

HTH

Reply to
hboothe

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