Thread: L36 Coolant Leak

My buddy ended up changing his girls intake manifold gaskets as they were leaking some. Well he finishes up the job and calls me later telling me he's got coolant in the intake manifold and TB. Well last week he calls me up and says the call refuses to stay running. It runs for about 3 sec and then stalls. I asked if the tach is working and he says yeah, as I thought he had a bad CPS sensor. I stop by on sunday for only a few minutes to run a quick scan with my snap on unit, and it gave me the bad CPS code. When I started the car, the tach also didn't work.

Fast forward to yesterday, he ends up replacing the sensor and calls me up saying its running, but smoking like crazy. I tell him he's burning coolant and he checks the TB/intake manifold and he can see some coolant in their. He tells me he used RTV at the corners of the lower intake manifold gasket like your suppose to do and cleaned the surface of the parts before resealing them up.

I've never done an L36 gasket change (plenty of L67's), but he's convinced his plastic intake manfiold is warped. How likely is that, as I know some manufacturers redesigned them to prevent them from blowing up, because of EGR tube issues, among some other things not to mention the L26 went to aluminum intake manifolds.

I'm going to probably help him this weekend if I have time.

It's all too likely, the heat from the EGR inlet warping or even cracking the UIM is not uncommon at all. The Dorman replacement reinforces that area, and there's another company that actually installs a metal bushing in the inlet. You can even use the UIM from the L26, but you need a TB adapter and have to rerun the lines for the PCV inlet and the EVAP. In my opinion, that's the best option, since it actually fixes the problem and not just band-aids it.

Originally Posted by Scimmia

It's all too likely, the heat from the EGR inlet warping or even cracking the UIM is not uncommon at all. The Dorman replacement reinforces that area, and there's another company that actually installs a metal bushing in the inlet. You can even use the UIM from the L26, but you need a TB adapter and have to rerun the lines for the PCV inlet and the EVAP. In my opinion, that's the best option, since it actually fixes the problem and not just band-aids it.

Who sells the TB adaptor to mate the L26 intake manifold to the L36 TB? As far as the PCV valve is concerned, that can be pretty easily dealt with rubber tubing and coupler. Whats the deal with the EGR? Is the EGR steel tube not long enough to reach the intake manifold? Do you know if the L36 intake manifold sensors are the same as the L26 this way they can easily be bolted in?

Thanks for the insight so far.


Edited for:

Found the L26 intake manifold adapter to L36 adapter on ZZP's site
https://www.zzperformance.com/grand_...ts1.php?id=255

The standard Gen V adapter that you can pick up anywhere should work for the connecting the TB. For the PCV valve, you'll actually need to drill and tap the brass plug on the bottom of the TB, and run that up to the inlet, which is on the top of the L26 UIM. They really changed up how that's routed. The EGR should be fine, but the EVAP system is different, the L26 has it mounted on the back of the UIM, so you'll have to block that off. Then, since the snout is longer on the L26 UIM, you'll have to extend the stock EVAP line to reach the nipple on the TB. Come to think of it, that same nipple is used for the FPR, too. Pretty much it's the same as installing a Gen V on an L67.

agrazela did a good write up on this, even if he took it a bit far. I have it bookmarked at home, I'll get you the link after work if you'd like. I did a bunch of research on this, and was planning on making the swap, but decided to to another direction at the last minute. In fact, I still have an adapter and an HV3 sitting around.

That would be awesome if you can get me the write up. I'll probably purchase the adapter off of you but I need to make sure my buddy want to go this direction first.

Also is the L26 LIM the same as the L36 LIM

Basically. Agrazela address it in his writeup. He's a member here, maybe he'll beat me to posting the link.

This is probably the write up your referring too.

BonnevillePRO.com • View topic - L26 aluminum UIM on L36--Done! With results!!

Yep, that's the one. He was trying to make a plug-n-play kit, so it was a little more complicated with the way he did the PCV, but it does the job.