Hello all! Quick question about intake gasket on a '96 Vortec 5.7L...........Have a significant vacuum leak causing high idle. Sounds like it is coming from intake manifold along 4,6,8 cylinder and maybe a bit from the rear of intake manifold near #8. Is this a very common prob? Can it be sealed without complete gasket replacement? Also, my 4x4 just went thru another transmission(they seem to last only around 100K in my truck.) Is this normal? Thanks, '96

 

We really don't see those intakes leaking vacuum...just coolant...but its bound to happen.
it needs to be replaced if thats what it is

 

depends on how hard you abuse it to the life of them. ive seen those go 300,000 with no serious fixs other then maintanence and body problems.

 

Thanks Arg and Stops!! I replaced the intake gasket and found the gasket had been replaced before I owned the truck because gasket was slid down towards the lifter valley so for that the #6 intake was not sealed off and part of #8 as well. One odd thing I found---while trying to find the leak, I employed the old ether-to-locate-the-leak trick. What shocked me was that direct application to the leak area(I found out later that I was spraying dead on that leak,) it actually killed the motor---choked it out big as anything. Exactly oppposite from what I was expecting. As for the transmission---stay tuned... Thanks again, Brad

 

Be careful with the ether.
I 'popped' my plastic plenum (upper part of intake) and burned my injector 'spider'. The plastic plenum was cracked in about 4 places and gave me fits until I pulled it and examined it real close.
Than goodness I have a friend in the wrecking biz.
paul