Think thermostat may be duff. Top hose to rad hot when up to temperature but bottom hose cold yet expansion tank full to overflowing and hot just on tickover.
Also noted that fan is running from cold, doesn't slow warm up as don't think anything is going through rad.
Hopefully thermostat is the route cause...
 
Fitted new thermostat but no better, still starts to overheat...
Top hoses and top of rad too hot to touch. Bottom of rad gets a little warm. Hose out of bottom of rad still cold. Thermostat body still cool. Starting to get disillusioned!
Is it worth buying a new rad or could something else cause these symptoms?
All advice appreciated.
Thanks
 
It is odd, started with a small oil drip, now cured bui I am left with a car I can't use...
I can't see how the belt can be wrong? It def goes round water pump which spins anti clockwise looking from front. Belt grooves go in grooved pulleys and flat side goes round water pump and idlers etc.pic attached.
Water pump is spinning but water seems not to flow through rad?
Struggling with this.
 

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If you look in the top of the expansion bottle. Please be careful with the hot water. Right in the neck is a small jet which is fed from the inlet manifold. If that isn't squirting into the tank maybe that will give you idea if the water pump is working. When you filled it did you run it with the cap off and topping up the level as it burped?
 
Thanks, I will check that.
I did fill with cap off. Also top hose off till it was full .then fit top hose and topped up header tank.
 
read somewhere that you need to get front end up and back end down (don't know how) so air rises to top. Don't know if this is an old wives tale though.
 
read somewhere that you need to get front end up and back end down (don't know how) so air rises to top. Don't know if this is an old wives tale though.
Click to expand...

True, idea is to get expansion bottle higher than any other parts of the cooling system so air finds its way up & into this...ideally O/S front end up.
 
stick your hand on the centre of the rad,pound to a penny it will be cold.do not waste your time trying to flush it,you will not succeed just replace it.ps when you refill the new rad use distilled water.
 
i have changed so many of these its unreal.the cooling capacity of the p38 is barely adequate,block a third of the rad and watch it overheat
 
Gave it a good flush out and put a new rad on it. Took it for a test run. It was better but eventually started getting hot. Jacked it up at front drivers side pretty high. Topped coolant up on tickover. A lot of air gurgled out. Rad is now getting warm to bottom so water is circulating better.
Took it for test drive yesterday up some demanding hills. Did not overheat and coolant level remained constant. Was OK today so very encouraging. Top hose still feels a bit firm so maybe still a bit of air in there?
Thanks for guidance.
 
Bit late but normally there is a small leak letting air into the system the first place to check for air lock is in the heater matrix and then the hose that runs from top of rad to expansion tank. the best way I have found to purge the air is to run with the cap off at 1500 revs and watch the air bubble be ready to top up and job done.
Sounds like you have it cracked so good luck
 
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