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Noisy Idle/Coolant leak

Flava601

New member
Hey guys. Anybody know what could cause my 2000 grand prix gt to suddenly start sounding really loud upon starting and idling? Started about a week ago. Sounds like an exhaust leak would sound or bad catalytic converter but that isnt the case. I pulled her up on ramps and crawled underneath with flashlight and inspected. Sound is mainly towards front of car. I also noticed a little coolant around the area where air intake body is. Anybody got any ideas?
 


I have a similar problem with my '98 GTP. The sound is loudest for the first minute after start up and then it almost goes any. It is loudest near the #5 cylinder exhaust manifold.
Have you found a solution yet?
 
Is there any signs of coolant in the oil? Should look like a milkshake. Check the underside of the oil fill cap as well.

Sounds like your leaking coolant around the TB due to the UIM being warped/cracked. If you haven't replaced the LIM gaskets it would be a good time to do that as well to avoid future issues. ineedparts.com sells a good kit for the UIM that includes everthing you would need to do the work. Been running mine for over a year and no issues.
 
Hey guys. Quick update. Mine was doing that exact same thing, (loud at startup then sound disappears). I removed the heat shield for the Exhaust Manifold and found that the manifold itself was cracked. Got a replacement from Autozone for $70 and problem solved. Procedure was pretty simple. Just remove motor mounts and allow engine to roll backwards a lil and spray bolts with some PB Blaster for easy removal. The rest is pretty self explanatory. As far as coolant leak I still have'nt found a significant reason. The oil isn't milky and the leak seems to have disappeared. My coolant reservoir did feel a lil greasy near the top when I rubbed my finger in it. Engine not overheating or anything. I've been keeping a close eye on it. Is the UIM job pretty hard?
 
I pulled my heat shield off and I too had the same problem, the exhaust manifold had cracked all the way around between the #3 and #5 exhaust outlets. It took me about 2 hours to replace working in a parking lot far from my tool storage. I'm not sure why Flava601 needed to "remove motor mounts and allow engine to roll backwards a lil". Everything was pretty accessable except getting the torque wrench straight to torque the flange bolts.
 
I think he meant remove the dogbone mounts from the rad support and then rock the motor towards the front of the car, thus allowing more room in the back ;)
 


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