Quote:
Originally Posted by gpuvalowski
I have a coolant leak on my 99' Park Avenue 3.8L.
I have found where it is coming from. When the car is running coolant is seeping out from under the Lower Intake manifold, of the passenger side just above the Water Pump.
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Are you sure the leak is NOT from the o-rings on the 90 deg. tube that comes out of the lower intake and goes into the housing for the belt tensior and out to the heater hoses at the other end of the tensioner?
Check oil for any signs of coolant in it from internal leak. It will appear milky rather than clear and dark. If you see signs, drain oil and refill with cheap oil and run a minute or two to get bearings covered by fresh oil. After replacing UIM, LIM, etc., you'll run briefly and replace the cheap oil again to purge coolant that got into the oil and will damage bearings.
If you do this, I assume the UIM has not been replaced. Have you owned the car since new? There may be circular date marks on the UIM that show the year of manufacture. Replacement UIMs don't have these--at least not that I noticed.
Replace the LIM gaskets with the metal framed ones from GM. If the upper were recently replaced you might replace only the gaskets under it and to the throttle body, but it would be penny-wise and pound-foolish to NOT replace the UIM while it's off. The EGR tube area will have deteriorated from heat and potentially will leak in the future. Dorman, APN, and others make modified UIMs. The Dorman comes with a smaller metal EGR tube that fits into the LIM metal and sticks up into the upper and improved sealing rings around the coolant tubes that go to the throttle body. The smaller EGR tube leaves more air room around the hot spots. APN, I believe, has a metal sleeve inside the upper to help spread the heat from the hot exhaust coming up through the EGR tube.
There are places on the web where people have listed steps for removal. I suggest organizing all screws and bolts into small groups and labeling them. The injectors lift up (wiggle out) and can be tied out of the way folding them back onto the firewall area. Replace injector o-rings, they came with Dorman that I had bought. If you find signs of leakage internally, change oil after motor is running again to get coolant contaminated oil out.