Head Gasket

**aussie** · 12-10-2011

OK, I just bought a 97 GP-GT, 166K Miles.

Was told by owner that the intake manifold gasket was bad, car was rediculously cheap so I bought it.

Here are my symptoms:
Rough Idle
Loss of Coolant
White smoke
High coolant temps

So I bought the UIM & LIM gaskets & started tear down, only to find both of these gaskets have been replaced at some time, obviously not too long back.

I have no coolant in my oil, but have signs of oil in my coolant - the overflow tank had a nice brown slime in it.

The engine runs great over 10MPH, runs like a top.

Its night now, so I have to wait until morning to finish the repair. and hoping for some advise here..
I have plugged the two water ports from the LIM to UIM with quicksteel, modified the water jacket on the drivers side of the LIM (behind the cover thing), I will install the new gaskets in the morning & work my way back to the top...

I have some other issues, Im not sure they are related, but Ill list them just incase:
Fans were not coming on at high temps, I could disconnect the temp sensor then re-connect & they would come on.
Heater was not working at all until I completely flushed all parts of the cooling system - now heat is working - but will not turn off - Vac Leak??
Cooling system was not transferring from/to the overflow tank, it is now, after the flush.

Thanks for reading :-)

**redlinepontiac** · 12-10-2011

if someone killed a head gasket on these cars they deserve a medal.

is there crud in the radiator?

**aussie** · 12-10-2011

I didnt notice a huge amount of sludge when I flushed the rad, I checked for any cold spots on the rad, and all seemed OK.

My major concern is that it seems like the UIM/LIM gaskets were bad, but upon tear down I found almost new looking gaskets, which really worried me..

**redlinepontiac** · 12-10-2011

you might need a new sensor, and did you put a new Tstat in it?

**aussie** · 12-10-2011

Yes to both, switched T-Stat prior to tearing it down & have a new temp sensor ready to go in.

**redlinepontiac** · 12-10-2011

well if your good you could install the sensor and if it doesnt help remove clean and return it

**Joe m** · 12-11-2011

im in the middle of doing a head gasket job on a 03 gt. dunno how they did but it happend. took the rad cap off and u could see the exhaust coming out while it was shooting water out every time the motor cycled.

**Hippo Machine** · 12-11-2011

The brown sludge in the overflow is probably just from the dexcool, and the flush cleared out a clog you must have had in the overflow hose. You tore the engine apart saw the LIM gasket was replaced and left it? Should have done it anyways, especially if the previous owner said it leaked.

As for white smoke that obviously means coolant somewhere.. idk where.

Fan might be blower motor resistor.

Heat... no idea.

**aussie** · 12-11-2011

Here is a list of what I have done:

Performed the LIM mod - Filled the two water ports to the TB & removed material to allow better cross flow to rear head.
Replaced: UIM & LIM Gaskets, T-Stat, coolant temp sensor, o'rings on the elbow to the LIM
Flushed entire cooling system, several times to get out as much gunk as I could, used peak radiator flush.
1/3 Can seafoam through vac line, rest in crankcase

And here is my current status:
Engine still idles rough, gets a little better when I disconnect MAF so Im gonna clean it.
Also have a VAC leak right at the two tubes on the TB, so between these two I think that will fix the rough idle.
Water temp fluctuates, but never gets too hot - Still some air in the system.
Too soon to tell if Im loosing any coolant, but there is nothing leaking around the UIM gasket.

Conclusion:
The engine runs a lot better than when I started, but still needs improvement.
I plan on changing the PCV, clean the MAF, change a few VAC hoses & then see where I am at...

**Hippo Machine** · 12-11-2011

Change the oil if you haven't already, the seafoam can get aggressive.

Bleed cooling system better.

Looks like you are really fixin up the engine, clean the tb as well.

**aussie** · 12-11-2011

Im trying hard to get it back in shape..

Its a very annoying process though. I have read so many posts & different opinions on these issues, but I have finally realized my problem is that I have multiple problems, all overlap each other and have made it hard to diagnose.

I will get it running right, its a very nice, rust free, and tight car. I think its well worth the effort.

**BillBoost37** · 12-12-2011

Fix your vacuum issues, ensure that the vac port on the line from the booster to the UIM is connected or plugged.

If that doesn't solve it, look for misfires and if it's just one cylinder trace it down, check plugs and wires.

Typically the UIM gets a hole in the area of the EGR pipe. That could explain the coolant previously. You plugged the two ports that feed that leak, so you should be all set.

One other trick to bleed/fill coolant is pull the t stat and ensure the lim is full. The put the t stat back in and finish filling the system.

**aussie** · 12-12-2011

I believe I still have some blockages, after about 2 hours of Idle & 40 mile drive, I am still bleeding air & getting fluctuations on the temp guage, but not over heating.
Have not lost any noticable amount of coolant either.

Engine is running better, I have narrowed my problems down to 3 definate problems, 2 maybe's
Vac Leak
injector o-rings
MAF dirty or bad

Maybe cat converter, or cracked UIM sucking air

Thread: Head Gasket - Sure seems bad... Please help me..

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