[Custom95Z]

I have a quick question and I think I already know the answer, but here goes. I was reading about the 92-97 LT1 engines and how they're notorious for blowing intake gaskets. On one of the websites I ran across, a guy said to put silicone around the intake ports of the intake gasket so that the original gasket would not blow between the ports and form a vacuum leak. ANYWAY...I did this..and once my father-in-law found out he almost went through the ceiling lol Now that I think about it, it does seem pretty outrageous that the silicone would hold up to gasoline...anyway..does anybody know how long this fix will last? Please give me some feedback lol Thanks ahead of time.

Paul

[302 Z28]

Certain types of silicone, like the high temp version used in gaskets, are perfectly suited for the application you mentioned. In fact GM uses it on their factory engines. It is not harmed in any manner by gasoline or motor oil.

Vince

[Custom95Z]

How high temp does it have to be? I used the baby-blue Versa-Chem 777 silicone? I think it said it was safe up to 550 degrees? I really hope I don't have to get that intake back off...i took all the bolts out and tried to pry it off to put another gasket set in it but it was STUCK..and I do mean stuck bad lol Thanks for the reply Z28

[Bumpstick]

Permatex makes some stuff called (Right Stuff) it has sealed all my engines since it came out... It will stick to machined alum better than anything I have ever seen... It fills about any thing and prevents leaks... Kinda expensive but well worth the money...

[NAIRB]

When I worked for Glenn Niebel, we used silicone on the intake gaskets, we would glue them to the head, and let it set up hard on the head, then we would also use silicone on the other side of the gasket during assembly, but we would spray the intake manifold with a silicone spray to keep the gasket from sticking to the intake during disassembly. I hand cleaned the heads, and re-used the the gaskets in many instances.

[Custom95Z]

thanks everybody...i'll definitely sleep a little easier now. Hopefully I'll have the Z back on the road tomorrow, then. Thanks again for all the replies...this has to be one of the most informative sites on the net.

Paul

[Dozier768]

i always use aviation sealant, you almost have to break the manifold to get it off once its been bolted down for a while, and it can be applied very thin and remain semi tacky until it gets hot, then its like superglue. its approved by the FAA for aircraft use and is impervious to nearly all solvents and has good thermal properties. i use it on all my engines: pan gaskets, intake gaskets, and i use it on transmission pan gaskets where silicone isn't a great idea "0 leaks at the pan". makes a good thread sealer too.

[chevypunk]

Bumstick has got it, The Right Stuff works wonders, it is kinda pricey but well worth it.

[troy-curt]

The only place you should use silicone sealers etc. is at each corner of the intake,and at each corner of the pan.I also use it sparingly on the water ports. I through away the end gaskets and use gasket maker there. I use gorilla snot on the pan and valve cover gaskets just to hold them in place. The gaskets are made to seal with out using sealer. Just my way of doing it.

Any excess or squeeze out winds up in the pan and stops up the pickup screen.

Probably what you read was on the vortex eng. For some unknown reason they are notorious for blowing the intake gaskets usually on high mile engines, but not always. HTH.

Troy,

[burnout87]

Just a foot note- only use the blue for water passages.
Red high heat - good for just abot anthing that leaks,easily removable.
Black-hi heat- hardest to work with(messy) but if you let it tack up a bit before assembling your parts-its one of the best lasting formulas around. But everyones right, definately NOT around the intake ports- (front and back of manifold,yes--around water passage is personal preference-BUT DEFINATELY apply on all intake bolt threads!)

[engineczar]

(front and back of manifold,yes--around water passage is personal preference-BUT DEFINATELY apply on all intake bolt threads!)

Intake bolts?

Head bolts yes, but I'm not sure why you'd put sealant on the intake bolts.

[trees]

Czar, some intake bolts go into the water passages and need sealant just like head bolts that strike oil. The fine print on intake installation sheets and some manuals direct the use of sealant on these bolts.

Trees

[troy-curt]

Silicone on bolt threads will affect torque readings. GM recommends 3M yellow super sealant ( guerrilla snot ). hth.

Troy

[engineczar]

I'll have to look at that one, I've never sealed the intake bolts because I've never had one leak. (GM recommends anti-sieze)That plus the fact that none of the bolts go into the water jackets might be a good reason. The outboard bolts are blind and the other four go into the lifter valley.
Darn it, now I'll have to recall hundreds of engines. I hope the parts store has enough sealant in stock.
I'm still trying to figure out which head bolts strike oil and Jed Clampett's dead now so I can't ask him.

Excuse my grumpiness, us old guys get that way from time to time.

[troy-curt]

Your right none of the intake bolts go into water, there fore they should not have any sealant applied.

And Jed Clampett`s alive and still playing music on Dixon st. here at Fayetteville Arkansas.

Yeh, I`ve been accused of being grumpy too. But at my age I have that right.lol

Troy,