Vacuum Leak??

[offroadking208]

Ok, so in December of Last year my car had the intake manifold blow out... go figure... It wasn't covered by warranty so we had to get the Manifold taken care of ourselves. When i got the manifold, i got the Dorman intake manifold, but it was for an 02 instead of a 00, so it is the "performance improved" manifold. The day i got my car back together and running the manifold leaked coolant, so after taking it apart again and putting some high temp RTV sealant around all the ports and got it back together. Ever since then, there has been a hissing sound when the car idles. It doesn't idle rough, doesn't ever run rough, even cold, but that stupid stupid hissing is still there. Any suggestions of what it could besides a major vacuum leak? Any advice will be greatly appreciated.

[offroadking208]

Oh, and the car doesn't leak a drop of coolant anymore, lol. Mabye if i buy a PI manifold from Ford racing (i know they drop in) instead of dorman?

[RF Overlord]

You might wanna ask your question over on CVN. They have a lot more experience with the 2V motors.

My first thought is that you can't put a PI manifold on NPI heads, so you may have a port mis-match that is causing your vacuum leak... :dunno:

[larryo340]

I'm not sure about a vacuum leak due to manifold, but coolant leak is possible as the ports are different from PI to non-PI. It might even be the intake resonating the intake charge much like the 4.0L SOHC Explorer plastic intake from '95-'01. Sounds like a leak but no vacuum loss, no driveability concerns, and no engine light. I would think if you did have a vacuum leak that the engine would run lean and kick on the engine light. Without being able to hear it my vote is on the plastic intake just being noisy.

Just my 2 cents

[offroadking208]

lol, that sounds like a good possibility. The coolant did leak the first time we put it on, but after we made gaskets for it it runs fine, no coolant loss whatsoever. It may be just the manifold being noisy because ive checked all the lines and such and they're fine. It does have a slight shake at idle but i assume thats because of the CAI, Throttle Body Spacer, PI Manifold, and Superchips "tune" (until i get a real one, hahaha). I do know that the Belt Tensioner is due to be replaced though, that has nothing to do with a hiss :-)