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intake swap

R

robjr80

New member
will an alum upper intake off of an 04 grand prix work on a 98 grand prix with the 3800 series 2 motor. I saw one at the junkyard and was just wondering. would be a lot better than the plastic one on my 98. if so is it as simple as just swapping them out or are there other things I will have to do?
 


It won't change anything materially for performance or any gains. You would need a throttle body adapter plate to use it. Other than that, it's a pretty easy swap.

If you are concerned about the failure that can happen from a plastic manifold leaking, pull the manifold and plug the coolant ports. I have a thread dedicated to modifiying LIM's that goes over it pretty well.
 


the stove pipe in the L36 and L26 LIMs are different diameters. you need to bore out the cavity in the L26 UIM for the L36 LIM stove pipe to fit.
 
Or move it over...or if your car has ever had the UIM done then the stovepipe should have been changed at that time.
 
in this pic, to the right of the t stat housing, you'll see a tube sticking up, thats for the egr. aka stove pipe, it goes up into the lim

001_zps7wcca76b.jpg



goes into the upper intake on the right side there.

004_zps95spfbzx.jpg
 


oh ok didn't know that's what it was called. I have some questions. I'm the same guy that posted about the white smoke and map sensor codes I can't get to go away. I changed the upper intake and gaskets for upper and lower intakes. should I have changed the stove pipe? also that little tube that snaps to the upper intake gasket is that the way the tube should be placed in the intake like in your photo. if so than I did it wrong. I put the curved end of the tube in the hole where the pcv and map sensor are located because that's where it looked like it would go. could that be what's causing me to get the map codes. this was the first time I've worked on one of these motors.
 
thats the way it came off a running n/a engine i got for the bottom end. so my guess is thats how it should be. i touched nothing, but lifting it off the lim.

when you did your lim gaskets was there coolant inside the lim?

it look anything like this? http://www.grandprixforums.net/threads/60667-97-03-NA-L36-UIM-Failure?highlight=failure this thread tells you why it happens talks about that stove pipe too and how it melts a hole int he upper intake. then it leaks.

or the coolant ports leak. why its best to seal them up.

if your was wet like that the egr stove pipe may be melted through and letting it leak still.
 
yes it did but not that bad. I kinda feel like a dumb*** now because I got 2 different sizes of those stove pipes and for the life of me I couldn't figure out what they were for. I still have them in the garage. the instructions with the intake didn't tell me anything besides how to torque the bolts and where the map housing and the vac hose in the back attached. looks like I'm tearing back into it. the gaskets are new and have barely been run do you think I will have to replace them again or will they be ok. thanks for your help man.
 
you can re use the gasket. check the upper intake for a hole in it like in bills thread there. if you find a hole you need a new upper intake pretty sure.

sealing them two coolant ports should fix that issue tho and not require a new upper intake.
 


so I have it in right if I put the bend in the hole under the map sensor housing? or is the bend supposed to be in the middle of the intake pointing up?
 
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