P38 4.0 SE help! Overheating problems

Hi

We had a problem with our RR overheating and thought it was a head gasket problem which we have now done.

We then went on a test run and there was still a problem! The car ran fine when not moving, temp stays at the halfway mark, but when you are moving its ok for a while then the temp goes up and the warning light comes on. The hoses were pressurised so, after reading lots of posts on here, we decided it looked like a problem with the water circulating.

We have now fitted a new rad and thermostat, water pump seems fine. Took a looong time trying to bleed the system up but eventually thought we’d managed it, hot air coming out of vents etc.

Took the car out for a run round the block and the bottom hose blew off, we believe due to pressure! Was the cooling system still air locked or is there a more sinister problem going on?

Any advice or tips to try would be very much appreciated. I’m not the mechanic, my dad is, but I try and understand what hes getting up to!

Getting increasingly concerned that it’s a slipped liner problem

sounds like slipped liner, when the heads were off did you check to make sure the block and liners were flush?

if yr dads a mechanic then he probably did check but its easy to miss.

also was the new stat checked?

when its idling are bubbles of air/gas entering the bottom of the water tank?

have you done a hydrocarbons test on the coolant?

When the heads were off the block and liners all seemed flush. No visible slip nor to the touch.

I doubt the new stat was checked tbh, he probably assumed as it was new it would be fine. Is this something that should have been checked.

We had the car idling and there were a few bubbles coming through the expansion tank which we assumed was just air locks in the system.

And no test has been done on the coolant.

Since the bottom hose blowing off, the system has been refilled and, fingers crossed, it ran ok last night. Only round the block though as we're a bit wary of taking it too far!

When its up to temperature the temp needle was sitting about halfway but when we were stood the temp started going up and the vents blew cold air until we started moving again. Not sure if this could still be an airlock problem? Trying to get hold of a compression tester to see if there are any leaks elsewhere.

Planning on taking it for a run up to Meadowhall later so if it goes bang you'll probably hear it from where you are!

i would keep a close eye on it. one thing is to check the little pipe isnt blocked that comes off the top of the rad, this causes some problems.

stats should always be check in a cup of hot water.

try and get it tested with the chemical stuff for the coolant. thats usually a good inicator of liner/hg trouble

if everything looked like one piece of metal with no gaps then i dont think the liners have shifted!!

Checked the little pipe as I'd read about that so I know thats fine.

Will see if we can check stat later, and I'll look into the chemical testing.

Thanks for the advice