5th Gen ('95-'99): lower intake manifold gasket replacement
#1
03-26-2016, 07:23 AM
lower intake manifold gasket replacement
I need some advice.My 99 z34 has the 3.8 and the lim gasket issue.Awhile back, a guy I know said he could r&r the coolant elbows.So, I said great.
He changed only one of the elbows, so I had to do the metal ones.Didnt want to deal with him anymore.He changed the lim gaskets and they leak again.Ive never done this, so is this repair something an average shadetree guy can do? Do I need any specialized tools? Ive got a chiltons manual.
I will probably need a new intake manifold. I thought I had seen an upgraded intake manifold maybe but Im not sure.Maybe it had better sealing properties? Thanks for any advice guys, I really appreciate it. Muley
He changed only one of the elbows, so I had to do the metal ones.Didnt want to deal with him anymore.He changed the lim gaskets and they leak again.Ive never done this, so is this repair something an average shadetree guy can do? Do I need any specialized tools? Ive got a chiltons manual.
I will probably need a new intake manifold. I thought I had seen an upgraded intake manifold maybe but Im not sure.Maybe it had better sealing properties? Thanks for any advice guys, I really appreciate it. Muley
#2
03-26-2016, 10:22 AM
Join Date: May 2013
Location: Nebraska
Posts: 5,278
These intake Manifold gaskets are a pain. The technician at the garage I go to told me that in most cases the new factory stuff is put on from the lowest bidder for these parts.
Hence there are issues with switches and recalls and stuff like that.
If these replaced gaskets are leaking then they may have got the cheapy gaskets and not the good ones. My Garage gets theirs at NAPA and he says they offer a warranty. It might not be a long one but they have replaced stuff that didn't work a few times for me, alternators etc.
But when they did all my 3800 motors 3 so far they are good yet and its been several years.
There are a lot of bolts to remove and put back on scrape the surfaces, make sure no debris gets into the engine. You will need to Torque all the bolts to spec make sure you have a good torque wrench for that.
Check youtube for this work on a video and watch it to see what they do. I always check that to make sure I see the little issues they deal with.
Good luck.
Hence there are issues with switches and recalls and stuff like that.
If these replaced gaskets are leaking then they may have got the cheapy gaskets and not the good ones. My Garage gets theirs at NAPA and he says they offer a warranty. It might not be a long one but they have replaced stuff that didn't work a few times for me, alternators etc.
But when they did all my 3800 motors 3 so far they are good yet and its been several years.
There are a lot of bolts to remove and put back on scrape the surfaces, make sure no debris gets into the engine. You will need to Torque all the bolts to spec make sure you have a good torque wrench for that.
Check youtube for this work on a video and watch it to see what they do. I always check that to make sure I see the little issues they deal with.
Good luck.
#3
03-26-2016, 04:11 PM
Join Date: Apr 2010
Location: Mentor, Ohio
Posts: 12,153
I've done a few LIM gaskets on the 3800. No issues, I believe all pretty basic tools. Since I like to clean the parts prior to re-install, that is what normally takes the longest. To be safe, plan a weekend to do the job (but it can probably be done in a day). Plenty of YouTube videos showing people doing this job.
I would recommend getting the metal core replacement LIM gaskets made by Fel-Pro. I have yet to hear of anyone having a LIM gasket fail after that.
I am not aware of any upgraded LIM (there are some mods you can do for performance and that's pretty much it). The UIM, there is a better aftermarket one out there that strengthens the area around the EGR stove pipe (to reduce it's ability to damage the UIM and allow coolant into the engine). There is also the 3800 Series III (aka L26) aluminum upper intake, with some minor changes bolts right up (over kill for most people).
I would recommend getting the metal core replacement LIM gaskets made by Fel-Pro. I have yet to hear of anyone having a LIM gasket fail after that.
I am not aware of any upgraded LIM (there are some mods you can do for performance and that's pretty much it). The UIM, there is a better aftermarket one out there that strengthens the area around the EGR stove pipe (to reduce it's ability to damage the UIM and allow coolant into the engine). There is also the 3800 Series III (aka L26) aluminum upper intake, with some minor changes bolts right up (over kill for most people).
