Thread: Unusual Overheating

I had an old 77 Range Rover that did the same.

Although I never pulled it down, I later learned that this can be a symptom of a blown headgasket, particularly if it blows from a cylinder into the valley.
Perhaps the first step is to take a compression test.

Regards Philip A

Thanks Philip, I was hoping it wouldn't be the heads as that would be the poor girl off the road for a while, (i.e. cost v my budget), but I'll look at that first.

Cheers!

I had a similar problem with my TDI yesterday. Although I have had it before, I knew what to do.

Have you checked your water level in the expansion tank? If you have a small/slow leak somewhere in the cooling system it won't show until the thermostat is operating almost on a continous cycle. It will eventually creep up to the redline if not topped up. In the mornings the tank looks ok as it has water, but open it up at full temp and it dissappears.
You also need to bleed the system well and at normal operating temps as this can cause air pockets and will show a similar thing on the temp guage. Also will overflow the water out the expansion tank due to the air pockets & steam generated.

I am replacing the P-gasket this weekend, but an living with this problem for now.

Thanks Luke, I'll give it a try on the way home. Though I'm guessing I have to be a bit careful opening the tank at operating temp? I'll let you know what i find.

ok......

I tried the bleeding the system technique, i did see a couple of bubbles come up into the expansion tank, but after 15mins that was it, used it the next day, and still the same, so I waited until i put the old girl in for her service today, and the mechanic has checked the compression for me, and we cant find any leaks, all are within tolerance.
He is going to try and flush the block and test/replace the thermo this afternoon, but essentially I am back to the drawing board. I've got to find a way to keep her cool at highway speed.

Any other suggestions guys???

When you say you replaced the radiator, was it with a new one - or a new core at least? If it was a 'good' used one it may still be blocked. I bought a used one once and just bought problems - never again.

Also, if you have to open the expansion tank with the engine hot, its a lot safer with the engine running - a lot of pressure builds up just after its turned off.

Seems to be a radiator problem - have you checked externally that is clean? The easiest way to do this is to take it out and look at it and blow through the fins with compressed air - likewise on the air-conditioning condenser when in-situ. If all seems fine, have the tanks taken off and get it rodded.

Before that; check that the ignition timing is correct.

Can you hear the viscous fan roaring when it gets warm? If not get a new one.

I replaced my dead condenser fan with a Davies Craig one for about $100; this is worth doing as well, as every little bit helps,

Cheers Charlie

Thanks Chazza

As the radiator and viscous unit are only a couple of months old, this should be fine, the mechanic also flushed the block and cleaned the temp sensor, and we replaced with a cooler thermostat, and all that has seemed a lot better. Next is indeed the condesor fans, cant believe it is on such a knife edge, but it is 32C at the moment.

Cheers