89Cutlass Posted February 1, 2003 Report Posted February 1, 2003 I was wondering if there was anything special i have to do when changing the plenum(intake) gaskets i bought new ones today and plan on doing it tommorow. i took the plenum off to change a broken vacum line that was under it. Now i find out that i have to take it back off and change the gaskets. Cause its leaking alot of air now. Quote
GPRACER Posted February 1, 2003 Report Posted February 1, 2003 A clean engine ia a happy engine, just be sure that both gasket mating surfaces are perfectly clean, torque the upper plenum bolts to 20 ft/lbs and use the correct bolt tightening sequence, use no rtv sealant! Quote
cmo1234 Posted February 1, 2003 Report Posted February 1, 2003 What sequence would that B? Ive got that too look forward to tomorrow... Also what happens if i dont have torque wrench. What if too tight? Ive got loctite though.. Quote
GPRACER Posted February 1, 2003 Report Posted February 1, 2003 you should try to find a torque wrench, borrow one if you can. You shouldn't need loctite for the upper plenum, (the lower one does require medium strength loctite though) as for a sequence, just start in the middle and alternate sides in an expanding X pattern so that torque is distributed evenly. This way you will ensure that no gasket distortion will occur. I personally do it in 2 steps, torque all bolts to 10 ft/lbs and then re torque them again at 20 ft lbs. Quote
GPRACER Posted February 1, 2003 Report Posted February 1, 2003 If the mating surfaces are clean, you will not need RTV. most gaskets are designed to work without rtv. You definately do not want any excess getting squeezed into the intake manifold when you tighten the bolts either. You may think I am full of crap, but I have seen people use way too much rtv in places where it's not needed. GM engines do use rtv and lots of it, but as a GM tecnician I have been taught where and where not to use it. The upper intake is NOT one of the places where it's necessecary Quote
OldsmoBeast Posted February 1, 2003 Report Posted February 1, 2003 go easy on those bolts i've got one broken off in there still......which reminds me i have to get the bastard out.....son of a..... Quote
GPRACER Posted February 1, 2003 Report Posted February 1, 2003 That's why torque is important, make sure all the threads on the bolts are clean also. Quote
Brian P Posted February 1, 2003 Report Posted February 1, 2003 If the mating surfaces are clean, you will not need RTV. most gaskets are designed to work without rtv. You definately do not want any excess getting squeezed into the intake manifold when you tighten the bolts either. You may think I am full of crap, but I have seen people use way too much rtv in places where it's not needed. GM engines do use rtv and lots of it, but as a GM tecnician I have been taught where and where not to use it. The upper intake is NOT one of the places where it's necessecary What about, when changing the lower intake gasket, where the bottom of the intake manifold meets the engine, the directions stated that you could use a bead of RTV instead of those rubber pieces. It's how my engine was assembled with originally too....is that bead of RTV prone to having probs too? i havent been able to find those rubber substitutes also...thx Quote
GPRACER Posted February 1, 2003 Report Posted February 1, 2003 Yeah, all the newer engines use rtv for that location when replacing the lower intake gaskets, That's not the area that usually leaks so it should be ok. Also, the lower intake manifold uses a much lower torque spec, 10 ft/lbs and the bolts require medium strength loctite. The part # for the correct rtv for GM engines is #12346192 you can probably get an aftermarket equivalent though. Quote
89Cutlass Posted February 1, 2003 Author Report Posted February 1, 2003 Well I changed the gaskets today and holy shoot man the car runs like it was 1989 and it just came of the line. I guess i did a good job. Quote
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