Hey all, I am the proud owner of a '95 Monte Carlo z34 beast with a horrid anitfreeze leak that has eluded me and my dad for about a year and a half now. We have previously replaced the heater core, and due to time constriants and a strangely fitting part we had to kind of shove a plastic hose on (that was around 5 years ago) and we had thought the hose had come off, but upon tightening it and refitting it better, there is still no change. The leak appears to be coming from under the engine behind the exhaust manifold, and we suspect it to be a cracked head. There are also some corroded pipes that could be a contributing factor.

Can someone who had a similar problem point us in the right direction?

Thanks in advance.

 

check the oil for antifreeze in it or the water for oil but i had the same problem and it was on a 1995 monte carlo ls with 3.1 and it turned out to be the intake manifold leaking down the backside of the engine.

 

Thanks a lot. I also heard of an alternator braket leak, and we have had the alternator done multiple times, so will reply once we get conclusive evidence.

 

The 3.4l DOHC engine might make respectable power for a v6 bit is a turd in the gm v6 family which is why it didn't last a long time. A head could be cracked or an external gasket leak. Coolant doesn't always end up in the oil or oil in the coolant, or coolant out the exhaust pipe. Sometimes it's just a straight up external leak. I suggest swapping a 3800 in or just keep the coolant full in your 3.4 dohc and check the coolant and oil every 2 weeks or 500km's.
My opinion might be slightly biased as I hate, that's right hate the 3.4 dohc engine.

 

I had this same problem bout 8 yrs ago on mine. so I pulled the engine and rebuilt it all the way through. turned out to be a leaking intake gasket of which coolant got into the engine through the exhaust stroke. I know the 95 3.1 are nortorious for intake leaking at 50,000 miles or so. now 8 yrs later on this still new engine with only 49,000 miles on it. It has a problem with leaking coolant down behind the engine. my quess is bad intake gasket (again) leaking out down the backside of my engine. looks like im pulling it again !

 

since when was a gm 3.4l v-6 a dohc??? would love to know that one. and 13 years experience yeah i can fix it. you are not working on my car if you think the 3.4 is a dohc when it's a push rod engine

 

why pull it and rebuild it again? see if you can get the aluminum gaskets and get rid of those nylons. shouldn't have a problem outta that intake after that

 

First, during the mid-90's GM DID have a 3.4 v6 DOHC (this is NOT related to the 3100 or 3400 engines you are probably thinking of). Google Image search it and you will find it.

Second, this thread has been dead for 2 years.

 

I think you should examine the oil for antifreeze in it or the water for oil but i had the same issue and it was on a s5620 carlo ls with 2.7 and it became the consumption numerous dripping down the rear of the motor. . . . . . . . . . .