'94 TS leaking oil. Again.

I replaced my '94 TS intake plenum and upper and lower intake gaskets last year, and as part of the procedure I replaced the badly-degraded rubber gaskets that go at both ends of the manifold (at both ends of the "V", one under the throttle body, one under the PCV valve or so).

A little more than one month ago I realized the oil puddle underneath the car contained -besides power steering fluid from a known leak- motor oil. When I investigated the origin of the leak, I discovered the <> rubber gaskets have disintegrated AGAIN.

I don't see how this gaskets could be installed incorrectly, so I have to conclude the gaskets that came with the kit I used (Felpro?) did not withstand the oil as they should. Either way, I need to replace those <> pieces of rubber again :mad:

Now: since I don't want to be doing the same thing every 5 k miles, can someone recommend a good brand for these gaskets? Is there a material (neoprene?) that would last longer in contact with the oil?

TIA!

I am assuming you used a dab of sensor safe RTV at each end of those gaskets. As far as Fel-Pro gaskets go, I have used them in other applications, and have been more than satisfied with them..however, there has been a lot of discussion about aftermarket vs OE on this particular engine, and several mechanics at work advised me to bite the bullet and go OE GM when I had to change the intake gaskets 3 or 4 years ago on my 95 3800, and no leaks to date
Jeff

Hello Jeffry,

Yep... I used the dab of black RTV on each end of these gaskets, but it looks like they (Ok... at least one of them) have disintegrated because of the oil. Touching it (it's quite difficult to see it) it feels like it's still soft (i.e. it has not hardened at all), but I can feel like it has split in half along it's top. Considering this thing is intended to be in contact with oil, I'm surprised it has failed like that in so little time/miles.

I wonder if all of these are made out of the same material... If someone has information about this, or some experience with different brands, I would appreciate your input.

TIA

I have never had any issues with Fel Pro and 3800's... I have used Fel Pro on the 88-91 Vin C, 91-95 Vin L as well... I have never had any of them leak...

I am very picky tho... when I get them torn down the surfaces are as clean as humanly possible... My last step is a good cloth and brake cleaner or acetone... after that I lay a couple dabs of Gray or Black Permatex sealant at the corners of the head/block.... I then apply a small amount on the bottom of the seal and set it in place, then I do the dabs at the corners again, set the intake gaskets in place and add my dabs yet again, then a small bead across the top the the end seals... Then I carefully set the lower intake manifold into place... I have yet to see one degrade so this is interesting...


As far as gaskets go... For the L27 1991-1995 Felpro is the way to go... I have never known these to have any issues in terms of quality... There are a couple other gaskets makers out there ROL is one of them, the Other being Victor Reinz( spelling ) any of those should be fine...

For the later 3800's( Series II and later ) I would recommend the GM aluminum gaskets, Felpro Metal Framed right behind those...

Hello JRS,

I don't think I was that meticulous when I replaced the gaskets on the TS :) I tried to clean everything very carefully, though :)

The problem I'm having is not with the intake gaskets themselves, but with the "intake manifold seal" (#124 below), specifically the one located underneath the throttle body (I think we are in the same page, anyway). I don't recall applying a continuous bead of Permatex black either above or below it, though... just at the corners of the block/heads interface :( I think the FSM mentions only the dabs at the corners...

I guess I'll have to replace the gaskets and seals again. Have you been able to replace the intake gaskets without taking apart the plenum?

http://www.justanswer.com/uploads/rmldaytona/2007-01-05_184256_buick_92.gif

We are absolutely on the same page. I have done this on Buicks, Bonnevilles and the Vans with the 3800 TPI Vin L.. I have yet to have one leak.. In general the seals you are describing will seep over time... Its the reason I use a little bit of sealer.. The seal should be impervious to oil and have no issues with it..

I have never pulled the lower intake without pulling the upper.. Just makes it easier to get to all the bolts for the lower and at the same time it gives me the excuse to do some smoothing and porting... LOL