LIM gasket metal/plastic

[jakegday]

hello all. im going to be doing my lower intake manifold gaskets... i was looking at autozone noticed the plastic ones are cheaper then the metal ones. both Felpro brand. i am willing to spend the extra money but dont want to if there is no difference. so are the metal ones actually better, or will i be just fine with the plastics?

[richtazz]

The metal ones are much better, GM offers them now and has discontinued the plastic framed ones.

[BNaylor]

Felpro plastic framed is fine. That's all i use.
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[jakegday]

well crap! 2 different answers from 2 very reputable members. can i get a 3rd?

[BNaylor]

The bottom line is it is your choice. Both work fine but no real proof the GM aluminum framed port gaskets work any better. The FelPro sure look nice too.


LIM/UIM Job on our Regal going back 2 years.

[jakegday]

ok quick question guys. after i replace these, i was told i should refill it with new oil and run it for a very short time, then change it again. do i need NEW oil to do this, or can i just run the current oil a little bit longer, then change?

[BNaylor]

It depends. Are doing this job as preventive maintenance or do you have an issue with the gaskets?

[jakegday]

i believe i have an issue with the gaskets. its either these, or a head gasket. i lose about a half gallon of coolant every 4-6 months. and when i cut my used oil filters open, the are warped/wavy as hell, suggesting that a good amount of moisture is getting in there.

[BNaylor]

Then just to be sure after the job is complete I would use some Seafoam engine treatment added direct to the crankcase to the old oil providing that nothing falls in when you do the LIM gaskets. About 4-6 ounces and run for about 15 minutes then drain. Add new filter and oil.

Seafoam helps pull moisture and antifeeze out.

[tblake]

I didn't know fel-pro made metal LIM gaskets for the 3800? I thought GM made metal, and fel-pro's are still plastic.

[richtazz]

Tim, Fel-Pro metal framed intake gaskets- MS98014T

The fel-pro plastic framed gaskets (MS95809-1 for VIN-K, and MS95977-1 for VIN-1) are still an improvement over the OEM, because they have metal compression-stop washers to prevent overtorquing and subsequent cracking. I believe the higher strength vs lateral force of the metal frame over plastic frame make them superior, just as the new metal framed gaskets for the 3.1/3.4 have proven themselves more reliable.

[tblake]

Dang Rich, if I'd have known Fel-Pro made metal ones for the 3800 I'd have used them in my 3800 instead of the stock GM metal ones. Oh well I guess. So far mine have been just fine.

[richtazz]

The GM metal ones are just as good as the Fel-Pro brand, so you're good Tim. Unlike the other MS980xxT sets, the 3800 set doesn't come with the valve cover and upper plenum gaskets like the others do. I understand the valve cover omission, as it isn't necessary to remove the valve covers to do an intake on a 3800, but the upper plenum set should be included like they are in the 3.1/3.4 and 4.3/5.7 sets.

[jakegday]

WOW!!! i cant wait to post pics of these!! they are bad! definitely in need of replacement.

quick question tho: obviously there is supposed to be oil between the lower intake manifold, and the engine. but is there supposed to be oil between the upper intake, and LIM??

[danielsatur]

I like metal, because plastic is going to age and cause problems.
The oil in the Inake manifold is from a bad PCV valve.