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leaking and surging... HELP!

U

uhoh0573

New member
i know you all have probably had this question several times, and i apologize if im a broken record, but instead of spending hours using the search button, i figured id just ask

my girlfriend hs been driving her 2001 gp/gt for over a year now, the problems started with the low coolant light being on all the time, regardless of whether it was full or not, then the car started surging, if you step on the pedal it would barely go until u almost floored it, then the rpms would shoot up and down, now it just surges up and down all the time as you accelerate, the car idles fine. most recently ive been noticing anti freeze laying in the intake manifold under the engine cover, it burns it off regularly and smells of the warm antifreeze all the time, the heat has stopped working efficiently as well. i havent noticed milky oil yet. my question is where do i start? could it be UIM? LIM gaskets? blown head gasket? any help is very greatly appreciated!
 


Time to change the LIM gaskets and coolant elbows (there are 2 of them). Then go from there. Also make sure that it's not the upper intake itself leaking coolant, as they have been known to warp/crack.On the surging, when was the last time it had a tune-up? Any CEL on? How about fuel filter and cleaning the MAF? I've seen dirty MAF's cause all kinds of strange driveability issues.I would find out where that coolant leak is asap and fix it before you wash out the bearings and spin one of them, thus creating a nice 3800 paperweight for christmas!Jay
 
It sounds like your coolant level sensor is dirty or has malfunctioned.

If its dirty its a result of a coolant leak which results in air in the system which leads to clogging.

You're going to want to replace the LIM gaskets as mentioned above as well as the UIM itself....they warp by the stovepot for the EGR and leak coolant.

Also as mentioned above, unplug the MAF and see if things improve. If not, its not the MAF.
 
ive been a pretty avid mechanic most of my life, but mainly on diesels and atv's. about how long do you think it would take the normal mechanically inclined person to put a set of LIM gaskets in and a new upper plenum/gaskets? where do you recommend to get and what brand of gaskets and upper plenum? where exactly do these coolant elbows reside, and what do they go to/from? i havent really had a chance to look this thing over.
 
Dorman UIM is fine.

It should come with the UIM gasket set.

You MIGHT need to buy elbows separately. If so, get the dorman ones. In the HELP! section at your local parts store.

for LIM gaskets get the Felpro permadry plus second design. FEL-PRO Part # MS98014T

The coolant elbows are located on the front of the engine. Since the engine is transversely mounted this would be the passenger side.

They go from the belt tensioner to the water pump and LIM.

Use dabs of RTV in the corners for the LIM gasket to ensure it both stays in place and does not leak.
 


Probably should get a set of injector o-rings as well as they may not seal up once they are disturbed from removing the fuel rail. There are 2 o-rings per injector.

If you plan on replacing the entire UIM then you may as well clean out the entire throttle body while it's off. They get gunked up over the years and like to stick. Mine was black as night when I cleaned it.
 
took a closer look at everything tonight, i see no water in the oil, and no leaks on the accessory belt side, the UIM is leaking between itself and the lower manifold, right on the front corner, directly under the throttle body end, pretty badly too i might add. i could post a picture if any of you want to see.
 
Let me guess, right around the one long bolt for the LIM, right? I had a UIM that was leaking there as well. A new UIM and TB gasket later all was dry.

Aside from the Dorman intake, I found another place that sells what seems to be a good replacement as well.

Click me--> GM Intake Manifold Kit - iNeedParts.com

This one has a steel insert around the EGR pipe and includes all the parts needed to install, including the new smaller diameter stove pipe for the LIM. I've had this one on my car for about 15K and so far it's leak free.

Jay
 
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