I'm going to do the intake manifold gaskets on my 03 Yukon in the next few days to hopefully get rid of the pesky P0171 and P0174 codes, rough idle when cold and other symptoms that have lead me to believe they are the issue.

Shouldn't be a biggie and there seem to be plenty of good DIYs for the job, if needed.

Now, the question I have is that should I use RTV on the gaskets or just leave them as is? Some DIYs say you should whereas some say nothing. So, I guess I could go either way, right?

If I use it, should I use it on both sides of the gasket (heads and the intake) or just one? No huge amounts, of course, just a small bead, I guess.

Thanks!

 

WE never add RTV on ls motors at the shop. Just check to make sure the manifold isnt warped, and get a new gasket for it.

 

Nay..

 

Negative ghost rider... Step away from the rtv

 

Get the super seal felpro gaskets from napa if you're that worried. They are like $70 but worth the piece of mind. Proper torque procedure is critical too

 

No RTV.

 

Dont do it.

 

No RTV. Just use new gaskets, make sure both surfaces are clean and straight, then do at least 3x torque passes starting from the center. I did 10x torque passes on my LSXRT, and I felt it get a little snugger on each pass. Zero leaks and trouble free

 

OK. I guess the decision is pretty clear. Thanks!

I bought Fel-Pro MS98016T set. Not from Napa, but off Ebay for 53 bucks. No sure if that's what you are referring to. I'm pretty sure that'll take care of the problem.

Well..., at least I hope it will

 

Yep that's them. They are much thicker than oem and they align over the headbolts, they don't clip onto the intake. Just make sure to clean the crap off the head bolts so they sit down low enough and then they are zero issues. They are thick enough that I wouldn't hesitate to reuse them a time or two if I had to pull the intake again. I also wiped them with WD-40 so they seal smoother, but others will say its a no no.