series 2 / 4.2 ENGINE COOLING ISSUES

[jaghea]

Hi, can any tell me how to check how you can tell if the engine is running with the thermostat is stuck open or stuck closed.The engine is reaching normal temp. Should there be pressure now in the system because when I try and take the pressure cap of the header tank there is no pressure. must the engine temp be much higher for that. Is it only when the thermostat opens that the system gets pressurized.Also the radiator only seems to get hot round the edges and bottom. The middle seems to be cold. I did take the radiator out before and flushed it through with a power washer..

please help,, many thanks Sav

[almcl]

If the thermostat is stuck open the engine takes ages to get to temperature.

If stuck closed, it boils.

Is the cap on the water rail sealing properly? It should be a plain cap while the one at the tank on the wing should be the pressure sort. And yes, expanding water (with the heat) should pressurize the system. If it doesn't you may have a leak some where.

If the centre of the radiator doesn't get warm it could be that the core is blocked and a re-cored or replacement might be a good idea. Take the old one out, lay it flat on the floor with the stub pipes pointing upwards and fill is from a boiling kettle. If all bits don't get warm that points to blocked off water ways.

[jaghea]

Thanks for the advice, I will let you know what I find.. thanks

[jaghea]

Hi, Just to let you know my findings, with regard to the radiator, it will need to be re-cored, as I did the test with the hot water. I tried to clear it with a pressure washer. but didn't work. I filled it with boiling water then added kettle descaler but that didn't work either,While I am doing this I will change the thermostat as well..

many thanks for the advice

[almcl]

Good luck with the thermostat housing bolts.

One of them is about 4 inches long and runs through aluminium. Dissimilar metal corrosion has been a problem for some in the past. Patience, a very well fitting socket and even a welding torch seem to help.

[jaghea]

Yes it was a pain but I managed . it was hard work. I tested the thermostat as well with hot water and it does open and close, but I have ordered a new one anyway.Now all I need to do is sort out the radiator.
I have had a quote of 150pounds to get it re-cored
but I am still trying to unblock it before I take it. My latest attempt was adding vinigar with soda crystals.. Anyway I will let you know what happens

thanks

[jaghea]

Hi, just to let you know that I had the radiator re-cored, fitted new thermostat. Fitted and al seems to be ok. Radiator getting hot all over and there is pressure when I open the header tank cap..

many thanks for all the advice
SAV

[almcl]

Hey, glad to hear it worked out.