Coolant Leak, rear of engine

[BLACK 346]

Hey Guys. I have a persistant small coolant leak that is coming from somewhere at the rear of the motor on my LS1. I originally thought the coolant blanking plugs were the culprit (and they were leaking). I have since replaced the o rings on them, but am still getting drops of coolant on the shed floor. Is their anything else, other than a head gasket that might be the culprit? I have just given the motor a good wash with hot water to eliminate any prior coolant from the blanking plugs that may have been dripping down, so fingers crossed.
Any advice appreciated

[vr5speedv6]

I had the same issue when a I got the SS, with coolant around the the blanking plugs at the back of the motor. In my case it was coming from the front of the motor and finding its way back under the intake, making it look like a head gasket leak.
They can also have porosity in the block, but that's probably unlikely.

[beno]

Have you inspected all of the heater hoses where they join the firewall?

[peter b]

Hey Guys. I have a persistant small coolant leak that is coming from somewhere at the rear of the motor on my LS1. I originally thought the coolant blanking plugs were the culprit (and they were leaking). I have since replaced the o rings on them, but am still getting drops of coolant on the shed floor. Is their anything else, other than a head gasket that might be the culprit? I have just given the motor a good wash with hot water to eliminate any prior coolant from the blanking plugs that may have been dripping down, so fingers crossed.
Any advice appreciated

Head gasket is unlikely there are a few possibilities
Heater hoses rubbing on back of drivers side head causing a leak
Welsh plug on back of head
A coolant leak from up front of engine transferring making you think it is from the rear.

[BOBGEN111]

I had my heater hose rubbing at the back cause my leak.

[Toddler78]

Good luck with it rob, Id look at heater hoses first. before anything else, I remember finding one on my mates car, thinking it was leak near the exhaust manifold (had no idea why it would be leaking there apart from a cracked head) after a few hours of pulling the engine down to get to it all, by coincidence ran my hand on the underside of a heater hose only to find a small hole

it was then spraying onto the engine and looked like the leak was from the engine

[aratic]

I just replaced all my hoses and noticed one of the new heater hoses touches the back of the drivers side rocker, but cant remember if the old one did as well

Hope you find the leak mate, and its a simple fix!

[sikss]

best bet is to pressure test the system and then you can see where its leaking from. a little mirror helps to see in the places that are hard to get at

[BLACK 346]

Thanks for all the replies fellas, some very helpful info in all of them. Will investigate further tomorrow

Cheers
Rod

[BLACK 346]

Hey Guys,

Rather than start a new thread thought I would add to this one. Where is the best place to source the upper and lower radiator hoses for an LS1 M6 Commodore? Whilst searching for the leak that started this thread I found a nasty leak from the bottom radiator hose where it connects with the pump. I also want to replace those OEM clamps with some decent ones. Should I just grab OEM hoses from Holden, or are their good aftermarket ones I can source?

Cheers
Rod

[klink]

Hey Guys,

Rather than start a new thread thought I would add to this one. Where is the best place to source the upper and lower radiator hoses for an LS1 M6 Commodore? Whilst searching for the leak that started this thread I found a nasty leak from the bottom radiator hose where it connects with the pump. I also want to replace those OEM clamps with some decent ones. Should I just grab OEM hoses from Holden, or are their good aftermarket ones I can source?

Cheers
Rod

Rod,

i had similiar ages ago and it turned out to be fine crack in the headder tank that ran along chassis rails etc then dropping out near back of motor, took weeks to find.

[aratic]

OEM hoses arent expensive from Holden, about $20 each for the main ones. Wouldnt mind betting they are cheaper than Repco or SC sell them for.

[BLACK 346]

OEM hoses arent expensive from Holden, about $20 each for the main ones. Wouldnt mind betting they are cheaper than Repco or SC sell them for.

Cheers mate, will just grab them from Holden then

[BLACK 346]

Rod,

i had similiar ages ago and it turned out to be fine crack in the headder tank that ran along chassis rails etc then dropping out near back of motor, took weeks to find.

Hey Paul,

My leak is driver side mate, hopefully it is just a heater hose or something similare.

Cheers
Rod

[klink]

Hey Paul,

My leak is driver side mate, hopefully it is just a heater hose or something similare.

Cheers
Rod

thats the sidde my tank split