Rear Coolant leak VP V6

[jaza-g]

Hi all,
Got a VP commodore V6. I have a coolant leak only once it is at operating temp. Once cooled down it doesn't leak. It is from the rear of the engine dripping down near the tranny (auto). I've had a look at the rear of the engine and can't see any visible leaks. Im not sure where it is coming from as the only visible leaks are coming from around the tranny housing. Rough idle and doesn't seem to be holding pressure in cooling system.
Thanks in advance!

 

[HarryHoudini]

Has the rear welch plug been replaced?,it sits at the back of the motor,Tranny has to come off to replace.Rough idle and no pressure in cooling system could also be a head gasket.

 

[VPRob]

heater hose outlet is at back of motor in the inlet manifold but with close examination you should be able to see that. I don't know if inlet manifold gasket leaks could be a culprit too.

 

[jaza-g]

Thanks heaps guys. I'm not 100% sure if the Welch plugs have been replaced. I have also done rigorous testing for head gasket leaks. I will have a closer look today if I can see where the leak originates. I've read a few places where people are saying manifold gaskets could be an issue to a rear coolant leak. Is there only the one heater hose up the back of the engine? This is a new one for me and I'm a little bit confused, I will try get some photos today. Thanks again.

 

[rambunctious]

I had a similar leak, turned out to be the water pump and the water was running along the sump and dropping off the trans.

 

[rambunctious]

I had a similar leak which turned out to be the water pump, and the water was running along the sump and dropping off the trans.

 

[VPRob]

much more likely to be inlet manifold gasket rather than head gasket. There is only 1 heater hose at the back. The original fitting is plastic (same as the thermo bypass hose in the front of the inlet manifold under the alternator. They can be replaced with brass fittings for a little more $

 

[jaza-g]

Awesome work VPRob. Took the intake manifold off and decided to replace the heater hose and the fitting with a brass one. New manifold gasket and all is good. Better fuel consumption, quieter exhaust, more response.. Works a treat. Thanks to everyone for the help. My welsh plugs are brass, cant see any rust or gunk around them. Think they r fairly new. Mad help from everyone tho. Cheers

I used this website as a guide for replacing the intake manifold gasket: Replacing VN-VR Commodore Inlet Manifold Gaskets

 

[VPRob]

thanks for the feedback jaza. Great that you got such a positive result