Hey guys just new to this forum. I just swapped in a new engine in my 2000 civic but I'm having an intake manifold leak. I've went through 2 gasket changes but still is leaking. I bought the 2000 gasket first and was leaking and then found out my rebuilt engine had a 96 head and I replaced it with a 96 gasket and is still leaking. I was wondering if the 2000 intake manifold compatible with the 96 head or do I have to do something to it to make it work.

 

Is the air leak coming from the FIA system:

 

I'm not sure but when I spray carb cleaner in between manifold and head the car sputters. Seems like the top lip of the intake manifold doesnt sit flush against the head. I read that there is four holes that is on the top part of the manifold that is part of the fia system but I havent tooken it apart to see.If it is can i just weld closed without it affecting the fia system? Where do you think I should go about diagnosing this problem? Thanks, any ideas would be great.

 

There's a difference in the 96-98 and 99-00 intake manifolds. Use the same intake mani as your head.

There's an extra set of holes in the 99-00 intake manifolds, something about a cold start assist, that's not present on the 96-98 ones.

 

I found out the hard way, during my motor swap, that 96-98 IMs are NOT the same as 99-00. They appear to be in almost every aspect, but they ARE different.

The 99-00 Manifolds have an extra air injection system built into them, with these tiny little ports that WILL leak air and cause ridiculous idle surge if you try to attach it to anything other than an OBD2b head.

Here is a pic of the air injection holes.




I ended up bringing mine to a local welding shop and having them seal up the holes. Took em 15 minutes and I was back in business, idle surge free, shortly after.



....I'm going to put this post in the "Solved Problems" thread in hopes people see it

 

Thanks guys. So I guess I have the option of getting a obd2a intake mani or plugging up those injection holes. Would the obd2a manifold bolt right on without making changes? Also if I go with plugging the holes would it affect the
injection air system? Thanks I guess I'm half way there.

 

on a 96-98 head, of course a 96-98 IM will bolt up and work perfectly.


The 96-98 head does not require the air injection system, so plugging the holes will have no adverse effects on your motor.

 

Thanks forty. I'll give it a shot and let everyone know.