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Thinking about replacing the upper and lower intake manifold gaskets?

tom5170

New member
The past few days I've been thinking about replacing the upper and lower intake manifold gaskets. I have some pooling behind the engine (front of the firewall) and it looks like its on top of the lower intake manifold. The sides around the upper intake manifold look wet as well. The gasket on the upper looks orange. I pulled the throttle body off tonight (which I've never done before and it was really easy based on watching youtube videos) and there was lots and lots of carbon build up in the upper intake manifold, is this normal?

Anyways, I've looked at numerous youtube videos of people doing this repair on their 3800 series ii (but different cars), and have read numerous things about this repair on forums, and honestly it doesn't look too hard. I haven't really done an extensive repair like this though. I usually do the small things (thermostats, water pumps, oil changes, transmission filter changes, serptentine belts, random sensors, etc).

I do feel quite confident in doing this repair. I have a basic socket set, but I may need some more extensions. I have a few wrenches, adjustable wrenches, needle nose pliers, pliers, breaker bar, catch pan, pry bar, screwdrivers, pb blaster, etc. I don't have a hook and pick set. I'm thinking about picking up some freezer bags from the dollar store to put bolts/parts in for labeling and I also have tape I can use to label connectors, etc.

I feel like if I take my time and label everything I can knock this out in maybe a couple hours/half a day.

The way the people were doing it on youtube, it seemed like it was a piece of cake. I don't understand how a shop can charge $600+ for this repair. After studying for a few days, it seems really straight forward.

How was it when you first done this repair? Is there any sequence I should do when disassembling everything? All the writeups I've seen were on other cars and not one like mine, a 2002 grand prix GT 3.8. How much are the gaskets? Which gasket kits should I buy? Do I need to remove the exhaust manifold? Do I need to remove the tensioner assembly?

I probably wont attempt this repair until another week or 2 when I get the money, but I'd like to study prepare myself.
 


Aluminum felpro gaskets are wanted, coolant elbows too, new coolant etc etc.

A shop can charge the labor because I think book time is 4-5 hours ish, then factor in the 50-60% mark up on parts and you are at 600-800 easy with tax and fee's.


I can say my first time was slower, but I've done alot of stuff like this so it only took a few hours. Can be done in under 2ish now if I tried and I have power tools.
 
100% do it yourself. I was in the same boat as you a few months ago when I did mine. Just take your time, label all the hardware you remove and clean everything before re installing.
 
100% do it yourself. I was in the same boat as you a few months ago when I did mine. Just take your time, label all the hardware you remove and clean everything before re installing.

how long did it take you to finish it? what model/year is your car?
 
3 hours my first time out. spend a hour cleaning old gaskets off.

once the fuel rail and wire harness is un hooked and removed theres nothing left really.
 


i didnt take one pic or label a thing, took it apart leave bolts in the part removed or in a little pile here and there. thats what the windshield cowl is for, tools and nut and bolt holder lol
 
Search on "eas y" without the space and my name. Look at L36 failure and how to mod a lim, those two threads can save you the $80 for the upper and keep you from ever having a failure.
 
alright sweet. I know there's tons of threads related to uims and lims but I wanted my own for questions I think of. this site is amazing lol.

anyways, do you remove the throttle body and alternator first? does the tensioner assembly have to come off as well?
 
Easiest way or fastest way?

Easiest.. and fastest.. kill the power at the negative cable, flop alt onto rear valve cover/firewall, yank off alt bracket, pull rear three plug wires from coil and flip onto windshield, remove connector to TB and map, fuel rail connectors, up comes the rail, then the TB/UIM in one. Take off the LIM, plug it.. reinstall with then put old UIM back on.
 


alright sweet. I keep staring at the engine and looking at everything and studying. I know I can definitely do this.

how many vacuum lines do I need to remove and which ones do I remove?
 
Disconnect the Y-hose from the throttle body, remove the brake booster vacuum hose from The brake booster itself, not form the UIM. There is a little plastic vacuum line on the brake booster hose itself that just pulls off. I think that's all the vacuum lines for an N/A. Take your time on the fuel injectors and rail. I sprayed some PB Blaster into where the o-rings sit to lube them up a bit. Helped a lot.
 
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