GM LIM gasket: Two more questions

[Chris11]

Believe me. I have bought many tools over the years so I can be a DIY guy. The Intake job however intimidated me. I read so much online about it I feel like I could guide someone to do it but I don't have the confidence to do it myself. LOL!

Both times with the Intake Manifold and Head I had an internal coolant leak not external. I too believed it to be a Head Gasket issue all along but who knows. Nothing I can do about it now. From my readings online it is not a common issue for Head Gaskets to need replacement on the 3.1L's but the Intake both upper and lower were. GM mechanic told me they were both cracked and needed to be replaced. Two months later I had another internal coolant leak (caught both early since I check my oil every couple days) and was told it was the Head. They used that Felpro kit I posted above and sent the Head to be tested. It tested okay.

I agree with you that the gasket looks a little crazy. Reading online and seeing people post pics of their Manifold Gaskets I always wondered why mine looked so different? LOL!

Again it's nice to see you're able to DIY on that job. I'd hold my head up high if I were you. Good luck with the rest of your work.

 

[rationull]

Originally Posted By: Chris11

Again it's nice to see you're able to DIY on that job. I'd hold my head up high if I were you. Good luck with the rest of your work.


Thanks. I am not finished yet, though! I was nervous going in because this is an internal-only leak and while I did have the coolant tested I wasn't 100% sure before tearing it apart that the leak was on the LIM -- could've been a HG in my case too. That's one of the reasons I posted this thread -- was happy to get some confirmation that the pic in the OP could plausibly be my leak.

 

[Chris11]

Gotta love BITOG! Lots of helpful people here. Hopefully everything works out for you.

Honestly for me having an internal coolant leak not once but twice has wrecked me! I guess it's like if you had a near death experience, say almost drowning in the Ocean that every time you see it, it brings back bad memories. I feel like for the rest of my life no matter what car I own be it a GM, Ford, Honda, Toyota or whatever, every time I pull the oil dipstick out I'm going to expect to see coolant in the oil. Every time I don't it's a good day! LOL!

 

[yonyon]

Chris11:
It's entirely possible that you had a simple intake gasket leak at first, but then that turned into a head gasket leak later. With the 3100 and 3400 you can't count on the temperature gauge to work properly when the coolant level drops below the sender.

I recently had one of those get me. It was one of those maybe one in four where the failed intake gasket leaks coolant externally, so there's really no question that's the leak. Once I got the intake off I could see this thing had been severely overheated. The heads had gotten so hot they partially melted the plastic frame of the gaskets leaving a visible line marking where it met the bottom of the head. At that point I recommended replacing the head gaskets (about $30 each) and letting the local head shop check the heads for $75 bucks each so there'd be no worries.

The owner of the car was sure the temp gauge never went past 3/4 so it can't possibly have overheated that badly. I wasn't about to spend the $200+ out of my pocket and put in another two hours work for a car that belongs to some other guy who refuses to listen to reason, so back together it went. During the first warmup, the brass fitting on the thermostat housing leaked, but the upper radiator hose was so hard I didn't bother trying to tighten it and out came the pipe dope. After that, any WOT acceleration would make all the rubber coolant hoses nice and hard from excessive pressure and removing the reservoir cap was plenty of messy.

That's how it goes though. With the intake gasket busted open, the temperature gauge might not show how badly the heads are being overheated. Checking for combustion gasses in the coolant tank isn't really an option because the conditions needed to test that could cause a head gasket leak as easily as detect an existing one. Changing out the intake gaskets usually fixes the problem, so the usual course is to cross one's fingers and do it.

 

[The_Eric]

Chris11, you should be able to look in through the oil fill hole and tell which intake gaskets you have.

 

[rationull]

Originally Posted By: yonyon

Checking for combustion gasses in the coolant tank isn't really an option because the conditions needed to test that could cause a head gasket leak as easily as detect an existing one.


What do you mean by this?

 

[Chris11]

Thanks yonyon for your informative post. That would make sense. When the Intake Gaskets leaked back in 09 it was January and very cold. I'm a short tripper (hence I do frequent oil changes) and never really let the car get that warm before I arrived at work from home. In fact I have never once seen the temp gauge go beyond the normal operating temp unless stuck in traffic while the car is idling. I did however once take the car on a bit of a ride just to be certain what I was seeing wasn't condensation from the short trips I was taking that Winter. No such luck for me unfortunately. I wonder if it was that drive that cooked the Head Gaskets? I guess I will never know for sure. Both times I had the internal coolant leak the coolant level in the coolant pressurized reservoir hadn't gone down that much.

The_Eric: All I have ever seen looking down the oil fill hole was some of the valves but I haven't really looked that hard around there. When I get a chance (it's too cold right now) I will for sure have a look and see what I can see. Thanks for the info.

 

[The_Eric]

Well, I could be wrong. My memory may be a bit fuzzy there.