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Intake manifold leaking coolant?

H

hansz92

New member
I have a bad coolant leak somewhere and it doesn't appear to be visibly leaking anywhere I can see. I did notice this fluid on top of the intake manifold (I think that's the intake manifold)that is an orangish-brown color and kinda looks like oil. I'm not for sure wether it is oil or coolant because I think I might have a slow oil leak as well. Does oil leak from this area? Or is it sure to be coolant?
image.tiff
 


if you have puddles over the lim bolts, "lower intake manifold" that would be called seepage, and its coolant. the thread sealant on the bolt threads is failing.

mine are also leaking, and i loose about 2 cups a day. its intake manifold gasket time.

im s/c, and your n/a. being a n/a motor you'll want to fix yours asap. it will leak sooner or later into the engine and mix with your oil, or hydro lock your engine. aka coolant in the piston cylinder. thats what causes a spun bearing in the lower end and kills your engine.
 


Thanks for the responses! I touched the liquid and it felt very oily... So I'm guessing that's what it is. So will I need to replace the intake manifold or just the gaskets?
 
chances are your lim gaskets are on their way anyways, due to the missing coolant, and not seeing a leak. most here will say the lim gaskets are regular maintenance for the 3800, so you are best off if you change the lim and valve cover gaskets. make sure you get the upgraded metal gaskets should you do the lim gaskets.

and make sure the valve cover gasket set comes with new gromits.
 
Pull the oil filler cap and look at the back side. If it has any white residue then its been leaking for a while.
My learnings on these cars, is buy one & do the LIM job right away. Peace of Mind and really should be part of the tune up process in my opinion...
 


Hello all....first post here :)......

Just got done doing the upper plenum on a recently purchased 00' GT (project car/105k mi.) with the Dorman kit.........$86 off of EBay. I know many have reused the stock plenum and just upgraded with the newer style gasket, but the Dorman plenum is/was beefier and fiber reinforced due to the reported warping issues of the old stock ones. Also, the newer gasket has different style O rings in the water passages aiding in sealing. I opted for the upgrade after finding flecks of oil in my anti freeze, and the oil pockets in the lower manifold mentioned here....so off it came.

So far everything is dry as a bone and tighter than the skin on a hot dog.....so far so good.

Bob
 
its usually a pretty good idea to replace the lim gaskets as-well while u have it teared down. literally like 30minutes more of work.
 
Yeah, I agree......"penny wise, pound foolish" I guess.........I just knew where the leak was coming from, gravity wise, so going any further was a waste. The old saying......"if it ain't broke, don't fix it"........so I left it alone.
I also have a converter to replace.........engine ran fairly well with an upper (cracked check valve) exhaust leak.......now that it's fixed it bogs like hell. Just shook my head and knew what it was...........common GP problem.
 
all you should need is the gasket kit. unless you r intake is cracked. ]

and that kit looks to be the plastic lim gaskets. make sure you get the metal ones.
 


Hans......check Ebay for the upper plenum kit. Like I said I ordered the Dorman, and for $86 it was shipped to my door. The Auto Zone one was $149. Also, the plenum on the Dorman kit was more fibrous looking instead of plastic in comparison to the stock one........it appeared much beefier.
 
I think the gasket in the Dorman kit was Felpro..........it had the black raised O rings in the coolant ports instead of the flat stock orange ones. Due to a slight amount of pitting in those areas, I put a light schmear of Permatex Ultra Copper around them before closing them up.......just for good measure.
 
Here is the info with pictures as to how/why the NA intake manifold fails.
http://www.grandprixforums.net/97-03-na-l36-uim-failure-60667.html

Most of the time when you see fluid on top of the motor it'll look oily and crappy because your motor was dirty to begin with. If you want to know if it's actually leaking etc. Clean your motor. Then look for leaks. It'll be much easier to determine which fluids etc. As for LIM gaskets filling the oil pan, that is very uncommon. Sure it can happen, but so can a head gasket, typically..it's not the case.
 
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