HELP PLENUM GASKET FAIL

[crashchemist]

I have a 1998 truck that I changed the plenum gasket with the kit from Hughes engines. I was using 1 quart of oil/week or roughly 200 miles. I changed the gasket and am now consuming 1.5 quarts a DAY. I took a pic through the throttle body and can see oil. Did I make a mistake? Any help would be greatly appreciated.

 

[dodge dude94]

It's possible the pan wasn't torqued correctly or the gasket is misaligned or torn.

 

[crashchemist]

I did use some silicone on the plenum gasket which Hughes engines does not recommend. Is any oil indicative of a plenum leak or is some normal? Also, in your opinion does this look like a significant leak?

 

[Shadow_Death]

I did use some silicone on the plenum gasket

Yeah I don't ever use RTV anymore. I stick to fiber and Fel-Pro gaskets. Using Silicone on any kind of rubber gasket tends to end in failure as the gasket doesn't get a good seal to the two mating surfaces. I think any oil in the intake should be considered a a significant leak. I'm not sure what would be cheaper, buying all the bolts needed separately and a new gasket or just buying another kit.

But hey.. lessons learned. You can't learn without making a few mistakes along the way.

 

[crashchemist]

Thanks for the input. I guess I will tear it apart again and be more careful this time.

 

[meistermash]

I actually have this same exact problem.
Did the hughs kit.
And she started burning oil again.
Today I got the intake off and the gaskit is blown. {not the steel inner just the outside paper looking stuff}
Not as much oil as the ops pic in the intake.
I didn't use any sealant like hughs said.
The set of gaskits I bought are felpro.
It looks like the same as the one in the hughs kit.
So now I don't know what to do to it.
I usually glue the shiet out of things when I reassemble them but didn't because hughs instructions.
Should I glue the shiet out of both sides and maybe Loctite the bolts? I have some of that canned high temp copper stickum.

Did the timing chain today as well. The old chain was way loose. Used a mopar performance double roller set. Very tight now. Shouldn't have put the water pump back on though because of the hose and that will make re installing the intake a pain.

 

[meistermash]

Ok so I got to thinking. {I know bad right?}
Those washers included are the cheaper ones with sharp edges on one side.
What if those bit into the aluminum of the hughs plate and the bolts loosened up later on?

 

[Yeret]

I'll second Dodge Dude with improper torquing as well as the usage of sealant. The plenum gasket really wants to go on dry. Also, a good quality gasket, like Fel-Pro, will further reduce the likelyhood of leaks.

I've read of several people having oil loss problems after the plenum repair, whether they installed an updated gasket or used the Hughes kit, and every one of said problems were the result of improper torquing of the plenum pan. It might seem like a pain to sequence and stage-torque the bolts but the plenum pan is VERY picky and if you mess it up...well, now you get to rip everything back apart again to do it over and THAT is a pain, LOL.

 

[dapepper9]

Tq sequence is extremely important. Sequence 3 or 4 times then all the way around 1 last time to verify.

As for using sealant, I'm all for it personally. I won't suggest transmission pans get it or head gaskets but nearly anything else i say go for it. Gotta make sure you use the correct one though. For a plenum, i would use the standard oil resistant black or gray. You do have to let that stuff cure though. You don't let it cure you're wasting your time

Sealant is my opinion. As for those of you blowing the gaskets again, it's actually somewhat common with Hughes parts. Better off with the gasket direct from mopar

 

[meistermash]

I think I had the felpro gaskit. Looks just like the felpro kit I got at the NAPA.
I followed a hanes for the torque sequence and values.
My theory is that a bit of vibration and those washers that were sharp, bit into the aluminum plate and then the bolts worked enough loose to lose integrity.
In my case, I have a fancy inch lb digital torque wrench and used that.
I'm going to make sure those washers are flat and chase the threads well and perhaps blue locktite the bolts.
Another thing, I didn't check if the hughs bolts were the same lenth as oem and that plate is 1/4' or more thick as opposed to the thin plate.


Where online sells oem mopar stuff reasonable? I wanted robbed, I'd go to the mopar/fiat dealer in town.
Those folks are clown shoes in a dumpster fire.
I think I may look at the valve seals while I have it all torn apart. Napa doesn't have them they say.

 

[dapepper9]

Same length as oem bolts are perfect for thicker plate. Did you loctite those bolts? Its not the washers, factory did the same thing

 

[meistermash]

Hard to say if I did or didn't Loctite them last go around. I have a hard time remembering what I did yesterday not alone what I did when I did the repair.
The factory keggar will be the replacement.
The one I did the repair with had the vaccum ports in differing spots.

eta: It might help if hughs sent me a plate that wasn't already warped.
Looked today with a square.