I've got a 99 Z34 with almost 225k on her and still running strong. But she's going through coolant pretty consistently and quickly. I did an oil change a couple weeks ago and the oil looked fine. But I KNOW those 3.8 engines are notorious for going through the intake gaskets and I want to know if there's a way to self diagnose whether that's the problem or not. I'd much rather figure it out myself instead of take it to a shop and get charged an arm and a leg.

I have the ELM transmitter and the Torque app on android that can tell me my intake manifold pressure, is there anything I can use from that to help?

Any help would be great because I'd rather not invest a bunch of money there if that's not the problem.

 

It's good to see another L36 5th gen Z34! These cars can take a beating that's for sure. Anyways, if I were you, I would go to Autozone (or any other comparable auto parts store) and rent a coolant pressure tester. Just follow the directions, and if there's any external leak, you will find it pretty quickly.

If it turns out to be the lower intake manifold gaskets, replace them with aluminum gaskets like the ones found here: GM ACDelco - Intake Gasket #GM-89017825

 

X2 on everything Zipper said. The coolant pressure tester tool is a great way to figure out if you have leaks and where they're coming from.

I recently changed my lower gaskets to the aluminum as well. Probably a good thing to think about doing if you have any leaks there

 

I love how these machines keep running!

I will definitely go that route. That'll save me a lot of mystery. If it doesn't end up being the gaskets, do you guys know where else the coolant could be going? I haven't noticed a visible leak anywhere. So I'm not sure.

As far as the gaskets go, I definitely plan on going with the aluminum ones. And if it does happen to just be the upper, I might as well do the lower at the same time since I'll be practically there anyway.

Thanks for the tips guys! Zipper, what mods have you done to your machine?

 

Anything else would probably cause other problems such as visible leaks (radiator hose, water pump, etc), or you would notice poor performance (head gasket). Check your exhaust and make sure that you don't detect any coolant coming out (white smoke, smell of coolant).

Btw, get some coolant elbows if you replace the intake gaskets. You pretty much have to brake the coolant elbow in order to do the gasket job. Something like this: http://shop.zzperformance.com/store/...nt-Elbows.aspx

No problem. My Monte has had a few things done to it. Probably the best link for almost everything that I've done to the Monte can be found here: http://www.cardomain.com/ride/205587...et-monte-carlo

The Monte has some decent power, but the mod bug is happening again in the next 6 weeks or so. 348whp is just not enough...

 

Thanks for the additional info man. I really appreciate it.

Right on man. I've always got that bug with anything I drive. It's hard to have the dough to do it though. I'll be interested to hear what you do to it next!

 

I went to our local AutoZone today and rented their coolant pressure test. Turns out there's a serious leak at what looks like the top right corner of my radiator. It just spews coolant when it gets up to pressure.

Nothing around the manifold though. What a relief!

I'm pricing out a new radiator and want to know if anyone has any experience or knows if there's any difference in the fit of one with the 5/8" core and the one with the 1" core. I'm assuming the thicker core cools better. But I don't know if it's worth the $60 difference.

 

Hi I just bought a 98 monte z24 love the car but today on our way to town the engine light came on and was flashing then when stopped at a light seemed to run rough and sputter off the line. Parked it at my grandmothers and shut it off. Looked under the hood and seen reservoir for rad was empty when I just topped it up. Started the car and was pouring white smoke out the exaust pipe. When I brought the rpm up a bit to see if it would clear it died now wont start. I'm new to this forum and a new monte owner please help.