P38 overheating but why?

ive always draine mine by taking a hose off the thermostat, where's the plug on the rad then???

At the very base, central about 21mm and made of plastic. Well i`ve undone something that lets out water, albeit slowly?

I was going to test the thermostat so will see if this drains any extra.

Regards, Robin.

Crabbo said:

At the very base, central about 21mm and made of plastic. Well i`ve undone something that lets out water, albeit slowly?

I was going to test the thermostat so will see if this drains any extra.

Regards, Robin.

Click to expand...

it will drain, fast, dont get under it or you will be soaked. thats from experience!!! lol

Evening all.

I had the afternoon off and thought I would have another go at flushing the radiator through. Oh dear, what have I done!!

Well, I got off to a good start and some drainage was occurring, so I put some radiator flush in and topped the system up. Ran the engine at idle for 5 minutes or so and the temperature rose to just below centre on the gauge....no overheating yet! Great!

Whilst waiting I sprayed some WD40 into the engine bay to clean up some of the water discolouring and next thing I know is a warning comes on in the instrument panel saying "transmission failure", I think or "gearbox failure". The engine immediately stopped and wont turn over any more.

There are no warning messages now, but the engine still wont turn over! I disconnected the battery, hopeful that it might reset something, I fiddled with the auto stick, but still dead! No warnings, all lights illuminated, but nothing, not in neutral, park or anywhere.

Catastrophic? Terminal, any ideas?

Thanks again in anticipation guys.

Regards, Robin.

I found out by accident why my p38 diesel was over heating after having the head, new rad, new thermostat, and new matriax. There is air traped in the system. When filling with coolant, keep the engine running, keep the cap off the header tank. Keep letting it blow the air back up, it can blow back up maybe five times and more. Everytime the thermostat opens it take more into the system. It could take an hour or more to fill it, annoying i know, but it solves the problem. The other reason is the rubber O rings on the matriax radiator, they leak and cause an air bubble. Its the design of the system that causes the air to be traped around the matrix radiator. Tom

As previous posts, rads. are a well known problem area on P38's and I have been there-flushed it-all clean. Bled it, no air lock. Flushed heater out, all clean. Replaced stat., no change. Replaced viscous coupling, no change. Followed advice on here, reluctantly as it cost £160, changed rad....guess what? problem solved instantly and permanently. Fill it with 50% good antifreeze/soft water mix (de-ionized is better) afterwards.
Remember that aluminium (Your block) expands more than cast iron when hot and this is when you stand more chance of the liner slipping.