Grand Prix GT 3.8 VIN K - Upper intake manifold

[DanP76]

Hi To everybody, It is the first time that I join a forum but I really need info from an expert, that does not have interest in taking my money.

My brother in law bought me a GP in very good conditions six months ago (99k miles then).

Few weeks after the check engine light started coming on and off (P0401). The car kept going very well and I kept resetting the code. Two weeks ago I brought the car in for a coolant flush, because the coolant (dexcool) is dark brown colored. The shop instead of changing the coolant performs a pressure test in the cooling system and the system doesnt keep the pressure. First diagnosis is Upper intake manifold - 630dollars parts and labour. Then before doing the work, the senior mechanic checks it and says head gasket, 1100 labor with just gaskets(not changing the manifold). After that I checked other two mechanics, 1 says its upper and lower intake - 800-1000 labour and parts and another one just upper - 900 dollars. All of the mechanics talked about possible hydrolock, water in the oil destroying the bearings.

I bought the full manuals (4 volumes) to repair the car and the job seems possible. The Dorman intake manifold is 150 dollars at autozone. I think about doing it myself, with changing also the lower intake gasket but I don't have tools (6 months in the country, coming from Italy, with a PhD and almost no money).
I don't have experience with jobs of this size but I have two hands, one head and time to put in it.
Do you have any suggestions regarding the tools that I should buy to do this job, keeping in mind a low budget?
If everything goes smoothly, how much time do you think I will need?

Thank you very much for all the info that you can give me.

Daniele

[DanP76]

I forgot to post that the Grand Prix is 1998, has 110k miles at the moment and still runs strong! Sorry about that

[marc-o-matic]

The first thing that needs to be done is determine if the head gaskets are ok.
http://buy1.snapon.com/catalog/item....re&dir=catalog
If ok then I would replace manifold(upper)and gaskets(upper and lower)
The only special tool you will need is a torque wrench or 2 (in.lbs,ft.lbs)
and plenty of time,since this is your first repair of this magnitude probably all day.
Make sure to follow the torque specifications and sequence.

HTH
Marc

[DanP76]

Marc, thank you very much for the advice, I ordered the leak tester, I'll let you know what is going to be the results.

Thanks again, daniele

[DanP76]

I checked with leak tester... no change of color! head gasget should be fine then and it should be the usual UIM.

Bought dorman UIM kit and fel-pro lower intake gaskets rev. 2. I am going to start the project tonight hoping to finish by tomorrow evening.

Quick question: In the GM manuals they said to be careful with the injectors o-rings, in fact to recognize one kind from the other they do that in different colors. In the dorman kit they are both of the same color, one kind is thicker (ID.290) and the other kind thinner (ID.370). Any idea wich one goes on the top or on the bottom?

Any final advice on how to deal with the UIM and LIM gaskets? they are the things that worry me the most. Anything else that could be tricky for a newbie?

Thanks!

[Curtis0228]

when removing the LIM be careful with the coolant elbow, they are fragile and like to break, just to be safe, get a replacement beforehand.
You should not have to remove the fuel injectors from the fuel rail, so just replace the lower o-rings (the thicker of the two).

[DanP76]

Hi to everybody, i don't have a garage and every night i have to switch the car from one side to the other of the street. so i kept buying the parts and had everything prepared but i didn't start with the project for being afraid of not having enough time. anyway, i finally found a mechanics that goes around with a schoolbus is really good and cheap and was willing to put the parts that i already bought on and that was the end of it. in four hours he changed the lower intake gasket that was half destroyed and the upper intake manifold that was starting to leak. the interesting part is that i a was pouring 1 qt of oil every 1000miles without seeing any loss of oil or dark smoke. it turned out that, since the intake gasket was gone, i was filling up the coolant system with oil and burning some of mixed coolant water at the upper intake manifold so that the level didn't change too much. anyway now it runs great, in 50 miles i will do another coolant flush and an oil change and i hope to be driving that car for many more miles.
thanks really to everybody, i really appreciated your help in the diagnostics and avoiding of fraudolent mechanics

danp