What symtoms might I see with manfild problems? Like if it was cracked or had a bad gasket, or if some of the manifold bolts were broken? I have a '93 Quest that has a few different issues and I'm wondering what to look for in manifold problems.
-Chris
When a manifold bolt, or two, is broken, the motor makes a ticking noise that increases in frequency with the rise in RPM. Sounds like a stuck lifter in a small block Chevy.
Also note that in many cases the ticking noise will go away after the engine has been running for a while. This holds true for broken studs as well as small cracks in the manifold itself. The reason the ticking sound goes away is because as the motor warms up, the metal expands and closes the leak enough so that you can't hear it.
OK...so as a non-car guy, what are the more serious and/or long term effects of leaving manifold problems?
In the case of broken studs, the exhaust manifold will warp. You'll eventually get exhaust gases in the engine compartment which will filter into the passenger compartment. I would expect burned valves at some point because of an exhaust leak. In an extreme condition, I would expect the manifold to crack. Oh, and the earliest thing to happen is that the noise will get louder and more pronounced.
and don't forget the massive power loss...
How would you know the exhaust stud is broken? Do they fall off or just when you try to get them off?
"How would you know the exhaust stud is broken? Do they fall off or just when you try to get them off?"
I've seen it both ways. On one side of my 94 pickup, the stud broke and the broken piece along with the nut was missing. On the other side, I thought I had a bad gasket until I tried to take the nut off - as soon as I tried to loosen the nut the stud broke right off. It was already broken, but just hadn't fallen off yet.
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