2001 xj intake manifold question

How likely is it to warp your intake manifold from over heated engine? Could it just be a damaged gasket? There is a whistling sound that occurs only when i let off the accelerator. When i pull the middle hose off of the intake manifold the noise will either go away or change its pitch. Any help would be appreciated.

thanks:banghead::banghead:

I'd check all the hoses under the hood first - the heat could have caused a vacuum leak.

Does it idle any different, like maybe higher or rougher. If there is a vacuum leak it should effect the idle quality.

the idle is fine except for the noise...it is really loud. the wierd thing about it is that sometimes it won't make the noise at all. for instance i drove it to work yesterday and it didn't make the noise at all. then today it made the noise all the way there and all the way back.


hopefully that helps
thanks

You may have a very small vacuum leak. It would have to be pretty slight not to effect the idle. I have not seen many manifolds on the 4.0 warp. I have seen splits in intake gaskets and exhaust manifold bolts loosen after severe over heating. I would first make sure that all the bolts on the manifold are tight, if it persisted I would take a can of carb cleaner spray and spray it around the manifold and hoses to see if it alters the idle when and if it does that area is your leak. Iam not sure that this is much help but it is hard to diag. without hearing the noise.

I totally understand the difficulty in trying to diagnose like this and thanks i will give it a whirl and see what happens. thanks

well it looks like i finally found the problem....i found a crack in the manifold while i was spraying the throttle body cleaner around. Now should i replace the whole manifold or can i have it fixed? I am thinking that i can get these manifolds pretty cheep from a junk yard. Anyone else have any input...looking for a cheap but effective way to fix this. thanks

Anything can be fixed but I dont think that it is worth it. The manifolds are not to expensive new, and there are aftermarket ones out there. A junk yard may even part with one if they have a bad engine with one. I think I would just go with a new one. I have never seen one of these intakes crack, you must have really overheated this engine.

where can a get a descent aftermarket intake manifold for an inexpensive price? Thanks and ya i guess i did overheat it pretty bad ooops!:biggrin::biggrin:

I havw not tried to locate an aftermarket company but I am sure they are available. I know that Jeep sells theirs for 299. msrp, so you should be able to get it from them for around 250 or less.

Glad you found it! A cracked manifold can be welded by any competent welder, but 99.9% of the time they'll do it ONLY if it's off the vehicle - which to me means replace it. (http://www.google.com/search?q=jeep+4.0+manifold&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:official&client=firefox-a)

Just a thought that if you are trying to save some money and if the crack is easy to get to you could probably use JB weld. The stuff is pretty good and I have used it on different things on jeeps when the cust just wanted to patch and cash was short. You just have to be sure to clean the area REAL good and leave it set for awhile.