INTAKE VALLEY GASKET LEAKS

CFD244 · May 19, 2026

Hi Folks

I just picked up a 96 campervan with a 5.9 Magnum. Regarding the intake valley gasket leaking...Is it a matter of IF it will leak or WHEN it will leak. Just wondering the importance of a preventative repair. 60 thousand original miles.

Thanks FABO

Desoto291hemi · May 19, 2026

Nope
If it’s not broke
Don’t fix it

Tommy

TT5.9mag · May 19, 2026

All magnums leak eventually. But it’s an easy repair so I’d say react to it when it happens. If it’s idleing normally and not using oil then don’t worry too much about it. It is something to fix if you have the intake off for ANY other reason. Be aware the 4 corner intake bolts like to break when removed. Soak them in penetrating oil or similar prior to doing the work.

Frankbassman · May 19, 2026

Follow on question for the experts: what's the consensus on gaskets for that plenum plate? Dry, skim coat of ultrablack, any particular good gasket?

(2000 durango, 85k miles)

Thanks,

-Frank

TT5.9mag · May 19, 2026

If you’re going to fix a magnum intake plenum use the kit from Hughes. Follow their directions.

junkyardhero · May 19, 2026

Frankbassman said:
Follow on question for the experts: what's the consensus on gaskets for that plenum plate? Dry, skim coat of ultrablack, any particular good gasket?

(2000 durango, 85k miles)

Thanks,

-Frank

i've done a fair amount of them, and have always used the felpro kit with the printoseal gaskets and i go in dry with them.

if you're going to do the upgrade/fix hughes or hipotek have a comprehensive kit for it. which... if you're there... whats another few duckets to do it up right?

Frankbassman · May 21, 2026

Good points, mine is not leaking so will leave alone but was curious. Thanks.

-Frank

volaredon · May 22, 2026

I have had better luck with the Victor reinz gaskets for that application vs fel pro
The fel pro are too hard of material and don't flex near as much. I've done it with fel pro and still had 1qt /1000 mile oil usage. Redo with Victor and oil use drops to 1 qt down at oil change time (every 4000 miles for me)
And yes that's with the 1/4" aluminum plate and not the stamped steel original one
I've had these same results on a few of my magnums

INTAKE VALLEY GASKET LEAKS

CFD244

"THE NEW OLDSMOBILES ARE IN EARLY THIS YEAR"

Desoto291hemi

FABO Gold Member

TT5.9mag

Two atmospheres are better than one

Frankbassman

Active Member

TT5.9mag

Two atmospheres are better than one

junkyardhero

FABO Gold Member

Frankbassman

Active Member

volaredon

Well-Known Member

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