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Discussion Starter #1
I actually have a couple of questions
I've replaced the UIM with a Dorman, and used the FEL-PRO LIM gaskets & metal elbows. I've gotten less than 20K miles on it since then, & now noticed dark black oil in the coolant. The oil is clean & clear, but a quart low, and the tranny fluid is also very clear, red, & full.
I've seen a couple of V8 mechanics using a light coating of oil on the intake manifold gaskets, but I installed mine on both clean & dry surfaces.
1) Because of the angled head mounting surfaces, does installing the LIM gaskets dry tend to slightly deform the rubber sealing material when torqued down? It seems like, because of the V shape, tightening the LIM would also pull the rubber beading down at the same time, mis-shaping it & affecting the integrity of that rubber beading,. Has anyone tried using a light film of oil so the rubber SLIDES down while tightening the LIM?
I've had the Upper plenum off twice, and replaced it the last time. Both times I noticed oil on top of the lower manifold, especially on the corners where the "hidden" bolts are.
2) Do the LIM bolts all need thread sealer on them, or is there another reason that oil would pool up on top of the LIM?
The instructions in my manual never said anything about the bolts being threaded into oil galleys or using thread sealer.
Thank you in advance for any help with this next repair. PS: I'm going to try the ATP UIM replacement this time.
 

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PCV causes oil fumes to recirculate in the upper intake.

You should be installing the LIM gaskets with RTV in the corners to seal between the end (block) and side (heads) LIM gaskets. You should also be using sealant in the LIM bolts, as they go into water jackets on the heads, and could weep in either direction.

The rubber around the ports hardly moves during torquing.
 

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When I have done this kind of repair, I clean up the manifold and the cylinder head port area with carb/choke cleaner. After it dries(pretty fast) use ZEP RED GASKET SEALER on the heads and on the intake manifold where it aligns with the heads. I would suggest after torque to allow a couple of hours for the sealer to dry and set-up. Also follow torque specs and sequence. This should do the job, it always has for me over the years. On another note, make sure to use FAST-GASKET RED from ZEP........
 

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Discussion Starter #4
Thank you guys for your answers. I will definitely use sealer on the LIM bolts this time.
So the Fel-Pro type gaskets should be installed dry then?
I guess I've never heard of ZEP red. Is it an anaerobic or a silcone rubber, or?? Did you use the ZEP with the newer thick aluminum gaskets like Fel-Pro, or the stock type gaskets?
 

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I actually have a couple of questions
I've replaced the UIM with a Dorman, and used the FEL-PRO LIM gaskets & metal elbows. I've gotten less than 20K miles on it since then, & now noticed dark black oil in the coolant. The oil is clean & clear, but a quart low, and the tranny fluid is also very clear, red, & full.
I've seen a couple of V8 mechanics using a light coating of oil on the intake manifold gaskets, but I installed mine on both clean & dry surfaces.
1) Because of the angled head mounting surfaces, does installing the LIM gaskets dry tend to slightly deform the rubber sealing material when torqued down? It seems like, because of the V shape, tightening the LIM would also pull the rubber beading down at the same time, mis-shaping it & affecting the integrity of that rubber beading,. Has anyone tried using a light film of oil so the rubber SLIDES down while tightening the LIM?
I've had the Upper plenum off twice, and replaced it the last time. Both times I noticed oil on top of the lower manifold, especially on the corners where the "hidden" bolts are.
2) Do the LIM bolts all need thread sealer on them, or is there another reason that oil would pool up on top of the LIM?
The instructions in my manual never said anything about the bolts being threaded into oil galleys or using thread sealer.
Thank you in advance for any help with this next repair. PS: I'm going to try the ATP UIM replacement this time.
It is possible the lower intake bolts could be allowing oil to seep up the threads. When I have done these is days gone by, I always use ZEP FAST GASKET RED on the bolts. When you do this, first clean the bolt threads so the sealer can set up and seal the threads. Let it dry/cure so the sealing will hold up. That should do it..... Jake
 

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