Originally posted by DougKraft: Yes they are red at night, Why's that???
Doug
Usually a vacuum leak and usually a vacuum leak caused by a cracked EGR tube. Does it idle fast? Could also be incorrect ignition timing or a couple of other things.
Manifolds will probably eventually crack even if everything is OK... But getting too hot (glowing) well definitely speed up the process a LOT.
Originally posted by DRH: Usually a vacuum leak and usually a vacuum leak caused by a cracked EGR tube. Does it idle fast? Could also be incorrect ignition timing or a couple of other things.
Manifolds will probably eventually crack even if everything is OK... But getting too hot (glowing) well definitely speed up the process a LOT.
Yes, the EGR tube was cracked and the car was idling fast. I'll check the timing as mentioned. Could anything be wrong with the cat. converter (clogged)?
Things usually crack due to rapid heat up or cool down...one way to help prevent it from happening is to have the manifolds ceramic coated. Takes longer for them to heat up, and longer to cool down...of course there is always the problem of opening you rear deck lid that has water on it and it spilling down directly on the front manifold...
...of course I would also check the above meantioned things as well
Tim
[This message has been edited by Mickey_Moose (edited 05-19-2002).]
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09:53 AM
May 22nd, 2002
Ian Member
Posts: 43 From: sunnyvale, Ca, USA Registered: May 2002
i have a 88 gt and at about 90,000 miles i replaced the rear manifold because it was cracked. i think that it was a combination of over heating and to much engine movement. i might suggest that you get urathane engine mounts and this will help on the engine movement.
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04:24 PM
FieroV6Dude Member
Posts: 215 From: Fife Lake, MI USA Registered: May 2002
The previous owner after replacing the front manifold twice used fiberglas header wrap to wrap both manifolds. It keeps the heat down in the engine compartment and is also supposed to help exhaust flow. It also helps eliminate the sudden change in temp that causes the manifolds to crack.
I'm glad he did them, I've wrapped headers on our race car more times than I like, use gloves, the stuff is vicious but works well.
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04:53 PM
PFF
System Bot
DR650SE Member
Posts: 1793 From: Cleveland, Oh Registered: Oct 2001
Yea, but doesn't header wrap make the headers age real fast? I hear that headers won't last as long as unwraped headers do. Of course this is a fiero so maybe a wraped one will last longer
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09:30 PM
Dennis LaGrua Member
Posts: 15762 From: Hillsborough, NJ U.S.A. Registered: May 2000
I believe that the main cause of the cracked manifold is cold rain water on a hot manifold. When you lift your deck lid in the rain it creates a waterfall over the front manifold. The heat shield provides some protection but cold water on a hot manifold really stresses it. There used to be a guy by the name of Mike Freed from Florida that sold a nice neoprene and metal rain gutter that would catch the rain water and divert it to the sides. It attached to the firewall and the rear deck lid and formed a U channel all along the deck edge. I'm not sure if Mike is making and selling these anymore but the rain gutter does seem to offer better manifold rain protection.
