SPANISH INQUISITION, P38 DIESEL OVERHEATING ISSUE

Hola from Spain.
I recently retired here from the UK and needed a Spanish registered vehicle. I was delighted to be offered a 96 P38 2.5DT Manual in Epsom Green with Spring Conversion at a very reasonable price. There is no such thing as a free lunch......It transpires that the Dealer bought it at auction, so previous history unavailable.

She will run for anything between 30 to 50 kilometres, then overheat massively. This usually occurs when the engine is under load in third or even second on one of the many very steep hills we have here. Normal running temperature the guage needle sits bang in the centre. When the overheating occurs, the needle instantly flips into the red, warning light on, into 'limp' mode. It is not a gradual climb, it is instant, like flicking a switch. On occasion, the needle has returned just as uickly to the 'normal' position and normal service has resumed. The breather spigot on top of the old radiator was blown out, but this was put down to old age/corrosion.

The Dealers have been very good about it. Last night I picked her up after they had fitted a new radiator, header tank & cap,and hoses. A new water pump was found to have been fitted recently. All went well, with the engine seeming to run cooler than previously. Then we got to a steep hill close to home and once again she overheated instantly and went into limp mode. I had to limp about 50m to get safely off the road. As we pulled up there was an almighty bang under the bonnet as the new radiator ruptured for about 6 inches across its top edge. Spanish Recovery Services are excellent.

There is no sign of emulsification in the oil, and exhaust emissions look normal.

Any advice gratefully received.........................

To start, the temp gauge is not analogue, but will show too cold, normal, or too hot. It won't gradually rise as you might expect.
You need to check if the new radiator was a genuine one or a cheap copy, then check for exhaust gases in the coolant from a blown head gasket as a start

With regard to the radiator, check the top tank. It should have a baffle half way along it. The diesel cooling system is a pretty poor design. The water goes in on one side, down half the radiator, back up again and out. If the replacement didn’t have a baffle in the top tank, then most of the water goes straight in and straight out, which means as soon as you put the engine under load it will over heat as there is insufficient cooling.

Can you hear the fan run when it gets hot, if the viscous fan is working when you start the car it should roar then quieten down, just because the fan is turning does not mean it is working, you can also test it by getting it up to temp then try and stop the fan with a rolled up news paper in england the Sun or sport are preferred as that is all there fit for if you can stop the fan its goosed if it shreds its ok
and as mentioned above make sure the rad has a baffle fitted, normally tested with a marble rolled side to side if the rads out or can be tested with a torch and small mirror, or start from cold and feel the top if it get hot evenly across the top and not get warm down the right side no baffle fitted.

Ignore most of that as just noticed the rad split which is quite a common fail on the dozzle rad

+1 newspapers test on viscous fan.

brianp38dse said:

Can you hear the fan run when it gets hot, if the viscous fan is working when you start the car it should roar then quieten down, just because the fan is turning does not mean it is working, you can also test it by getting it up to temp then try and stop the fan with a rolled up news paper in england the Sun or sport are preferred as that is all there fit for if you can stop the fan its goosed if it shreds its ok
and as mentioned above make sure the rad has a baffle fitted, normally tested with a marble rolled side to side if the rads out or can be tested with a torch and small mirror, or start from cold and feel the top if it get hot evenly across the top and not get warm down the right side no baffle fitted.

Ignore most of that as just noticed the rad split which is quite a common fail on the dozzle rad

Click to expand...

Wot he said.

You don't want to know the elephant in the room.

brianp38dse said:

Can you hear the fan run when it gets hot, if the viscous fan is working when you start the car it should roar then quieten down, just because the fan is turning does not mean it is working, you can also test it by getting it up to temp then try and stop the fan with a rolled up news paper in england the Sun or sport are preferred as that is all there fit for if you can stop the fan its goosed if it shreds its ok
and as mentioned above make sure the rad has a baffle fitted, normally tested with a marble rolled side to side if the rads out or can be tested with a torch and small mirror, or start from cold and feel the top if it get hot evenly across the top and not get warm down the right side no baffle fitted.

Ignore most of that as just noticed the rad split which is quite a common fail on the dozzle rad

Click to expand...

Glad to see your carrying the baton for me ref. The sun.spit,spit spit.