Intake Manifold Gaskets vs Head Gaskets
 

To make a very long story short......it would appear that I am getting air into my cooling system, no matter how many times I have tried to get the air out of the system I always end up with more in it. The symptoms are: coolant getting pushed into the reservoir and the temp gauge has large fluctuations from the 1/4 mark all the way to the red line. It never reaches the point of setting off the dummy light for overheating so I am not convinced that it is getting too hot. I have just replaced the thermostat, coolant temp sensor, water pump, lower radiator hose and radiator.

I have been reading alot on the forums and I think I may have read too much. I am somewhat bewildered at this point and I am not sure if the intake manifold gaskets are the issue or if a head gasket is failing. I have no signs of coolant in the oil.

Any way to test which condition actually exists?

First you need to do a cooling system pressure test. Pressurize the system to 15lbs and see if it holds pressure. If it holds pressure [30-60min], then nothing is wrong. You just need to fill up the system when it's fluctuating like that, because it is probably just low

If it doesn't hold pressure and there aren't any external leaks then it would get into the oil. If it doesn't smoke then it's not the head gasket. It would show physical signs on the dipstick... a chocolate milk looking colour and the oil would be overfilled, if there were coolant in the oil.

Sounds like you just aren't getting it full. When you talk about the major temp fluctuations you mean it will go from 1/4gauge right to red very quick, then at some point drop very quickly back down to 1/4gauge? That is air, but usually air in the system doesn't make coolant rush into the overflow tank.

Did you replace all those parts to try cure this problem or were they replaced for some other reason?

EDIT: your radiator cap is on tight right? The arrows should align to the overflow hose. A failed cap could possibly be the culprit; that would explain the overflow rushing.

The system does need a pressure test... But at 283,000 miles the lower intake gaskets on this engine are more than due for replacement.. Also check to make sure you have no leaks

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Sounds like head gasket failure to me.

Here's the update guys.....

I went out tonight and checked all the plugs and found no traces of coolant. I then pulled the oil pan plug and again I found no coolant. I pulled the radiator cap and started the engine. As the engine started to warm up the coolant started to swell and a few air bubles came to the top. Seems like no big deal. Eventually the electric fan kicked on and then the coolant started puking out of the radiator. It seemed to calm down so I thought maybe I would add some more coolant, thinking that I just had not gotten all of the air out of the system. Everytime I tried to add some the radiator would puke it all out. It was not like a geiser or volcano errupting it just would gurgle really good and puke it out. Since it was somewhat humid here tonight and the temperature was somewhat cool I am not certain that I was getting any smoking. The exhaust really only smelled like exhaust. However, I did notice that later my hands did smell like hot antifreeze.

I am going to check with a couple of local shops to see if they have any of the sniffing equipment to test for coolant in the exhaust and combustion gas in the radiator. I'll see how much it costs first and then decide whether it is worth it or not to be 100% certain that I have a blown head gasket. All indications would lead me to say I am fairly certain that the head gasket has gone. I am glad however that it did not cause a catastrophic failure of any kind. I still have good oil pressure and the engine sounds as good as it ever did. So with a lot of labor and new gaskets it should be running fine again. I do think though that I will be looking for another car with a few less miles to get me to work and back. Other than gaskets and sensors and wear items I havent had to do anything to this car and it runs beautifully and the tranny is in great shape. Hopefully I will get it road worthy again. Its too good of an engine and tranny to not have it going down the road.

I really appreciate this web site and everyones help. Hopefully in the future I will be able to contribute more and not just be on the receiving end of the knowledge.

If you decide to do the head gaskets.... Get the Fel Pro head gasket kit... It will have all of the seals and gaskets you need for the whole top end.. Also you may have to order a set of head bolts( Fel Pro also makes those )...

Let us know what you find

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It really does sound like a bad head gasket. The exhaust gas sniffer in the coolant recovery tank will tell you for sure, but you have all the typical symptoms. We always try to eliminate every other possibility first, as head gasket failure is a rare thing with this engine.

Bill .... I sent you a PM. Thanks.

See PM reply, Matt.

You say you bled the cooling system, but is the air out of the heater core????

I remember when i did a heater core change, and when i filled it up, ran it for 10 mins. Temp guage kept running funny, and I figured it might have air in the core. Put the front on an elevated surface, (a set of car ramps did the trick) and the air should come out of the core, and you might hear some bubbling. I know as soon as I got the car on those ramps, I heard it, lol.

Might be something to consider?