Overheating

[RSR11360]

P3 75 1948 6 light saloon . I have owned this car ( 96000 miles only ) for about 3 years and it has always gradually got hotter to the point where it will boil if not nursed along , steep long hills causing the problem mostly . I have removed the engine and pressure washed the block , removing the water side plates and carefully cleaning the water ways in the head as well . I have now had the rad recored and more recently romoved the stat . there is some improvement with recoreing , but not a cure . I have been thinking of fitting a Kenlowe electric fan to see if this will cure it .

Has anyone else had this problem , surely all P3s don't behave like this . Any suggestions would be appreciated .

Jim Perriam Exeter 01392 413406

[deckell]

Jim i have had this same problem, i have cleaned out the system with some you beaut cleaner but i am not so sure how you beat it is because it did little good.i have since cleaned out and back flushed the block and had the radiator recored.i am in the process at the moment of refitting the radiator to the vehicle.i hope i am going to fix the problem.on inspection of the old core it was about one third clogged up.i will keep you posted on my progress.best regards Derrick.Smith

[lakesrally]

I cleaned the block out when the engine was restored 20 years ago but have not recored the radiator and the thermostat is still in the car. While the P3 has suffered various running problems it has never suffered from overheating, I've done a lot of miles in it up steep hills and motorway driving from one end of the country to the other so, though I cannot help with whatever is wrong I can at least confirm that it should not overheat. Mind you, I live in the English Lake District, not Australia! Best of luck.

[deckell]

Jim i have now replaced the radiator and have been for a 20km run with the outside temp at 31degrees,the gauge did not get over 82 degrees at 50 mph but no hill climbs hope fully the problem has been remedied, i also fitted a 71.4 degrees thermostat instead of the 75 degrees original the true test will be when i go for a longer run in the hotter part of the day. previously when the problem began to get worse i fitted a thermo fan with manual switch which meant i could activate it when i was approaching a rise or a steep climb. but after some time as the radiator became more clogged the motor got hotter so i decided a recore was the next step i also put the thermo fan back on just in case it might be needed in the future.we do get high temperatures in this area of queensland.best regards Derrick.Smith

[Chris C]

Hi Derrick, My P3 was running hot (95+) over a long period, but never actually boiled over.

Recently it developed a water leak on the large side plate next to the dynamo.
So after removing it and tig-welding various thin parts of the plate, I flushed out
all of the rusted debris in the bottom of the water gallery. There was so much debris,
it was level with the lower lip of the side plate hole. Now all sealed and back together,
the engine is running at 75 deg and only going up to 80 deg on a long up-hill runs.
I think that the debris acts as a heat-sink and reduces the cooling effect.

Rgds, Chris C.

1939 - P2 / Rover 14
1949 - P3 / Rover 75

[RSR11360]

Hi Derrick , Chris and lakesrally , thanks very much for all of the information that you have posted .


I have now ordrered a Kenlowe electric fan and hope that this will sort it out .

Regards , Jim Perriam , Exeter

[Freewheel]

Jim,

One thing: Have you checked the aluminium bottom hose connector casting elbow ?
- This can fur up inside and limit flow.

Also can we presume the thermostat hasn't failed [closed]?

I\m thinking of a physical change consistent with your overheating observation...

On my P3: slight fizzing at the radiator cap was due to failure of number 1 cylinder liner - which had a wall thickness of just c. 2 mm
- But on this car and the P3 before it: the alloy bottom hose casting gave bother.