1994 VR Commodore Idle Problem And oil residue on radiator cap

[DeluxeVR]

Hello, I've got a 1994 VR Commodore automatic that has been given me the shits, just replaced the majority of everything in it from harmonic balancer, to bushes and what not anyhow when I bought it, it would stall out after a few seconds of idling, after replacing harmonic balancer n sparkplugs it doesn't stall out but goes from 1000 rpm to 700rpm to 400rpm while idling. That's a problem I'm not sure with. the other problem is that I went to open up my radiator cap and it had oil like residue stuck to top of cap and around top of radiator, when I took it in for road worthy they told me the valley gasket is fked, could that cause a leak into cooling system? Anyhow I wish to find the problem ASAP as I just want to get it on the road, a few mates reckon it's a cracked head but doesn't over heat at all. Would appreciate if you guys could help me out thank you.

 

[losh1971]

Cracked heads and leaking head gaskets on the VR are not common, except they tend leak oil down the side of the block. What is very common in manifold gasket leaks. And oil does contact the coolant in this case. It is fairly straight forward to do but does take about 3.5 - 4hrs, about 1hr of time is clean up. If you plan to replace them yourself, just make sure you smear the gaskets with a thin layer of oil. This helps the manifold move into position without damaging the gaskets. Also squeeze a blob of RTV on each end of the rubber seal, that sits on the front and back of the block.

 

[DeluxeVR]

Fair enough, will that also be making it low idle?

 

[losh1971]

Hard to say. If it is causing a vacuum leak it could affect idle. Probably best to fix the manifold and go from there. Normally clean the TB and elbow, when replacing gaskets, so that might help it idle better too.

 

[DeluxeVR]

Thanks mate, I'll tell you how I go.

 

[vs-lover]

One thing to remember and that is Oil Pressure is greater than cooling system pressure and that's a good thing as it's better to have oil in the cooling system opposed to coolant in the oil. Regardless I strongly feel that it's time to do the valley gaskets and this will set a datum point to eliminate that part which is a common failure at this age for these engines.

This is one of those jobs that requires a bit of patience and methodology behind it, but not terribly hard I might add.