1999 Citroen Xsara Turbo Diesel Overheating At Speed

[b1981ci]

The car overheats rather quickly bit only at high speed on the highway (160-180+ kmh). This is the only time it does it though. Drive below 160 and it's fine. I thought maybe it could be the thermostat but if that were the case I would expect problems at any speed.

Car otherwise runs smooth, no noises, no lack of power, fuel mileage is great, etc.

What could be the cause of this and how do I if it.

It is an "xsara break (n2)" by the way. I guess this car must have 1.9 or 2.0 if this data is accurate http://www.auto-data.net/en/?f=showSubM ... li_id=1693" onclick="window.open(this.href);return false;

[Xantidote]

Does it overheat on a hot summer's day when stuck in traffic? Do you then see the needle keep climbing on the temperature gauge? And in those conditions, do you hear the cooling fan(s) cut in?

The radiator's not blocked with leaves is it?

PS. Welcome to the Forum

[b1981ci]

Thanks. No it doesn't overheat at slower speeds or stuck in traffic. I don't see anything blocking the radiator. I did not realize now close this is to the engines absolutely top speed because the tach reads low. It is probably not a great idea if for fuel mileage alone to be driving that fast all day every day but it seems to me like a car should not overheat (and rather quickly at that) just because you are approaching the vehicles top speed for 15-20 minutes

[Peter.N.]

Diesels will run hot when driven hard especially at high revs as they rapidly loose efficiency once past the max torque speed and consume a lot of fuel, little of which gets converted into power. If it overheats driven gently at high speed most likely the radiator is clogged.

Peter

[Old-Guy]

If the radiator air path is clear, then I'd suspect a partial blockage in the water flow; silted up cooling system or a tired thermostat. I've recently changed The Green Lady's thermostat for the second time (after 7 years) because she started to get a bit hot and bothered when driven hard. Old thermostat was opening almost fully but only close to 100C. New thermostat has fixed the problem - temperature still rises to 85-90C on the gauge when driven hard on a hot day but no further and the slight loss of coolant has stopped too.

Incidentally, Gates thermostats come with a sealing ring, most others don't and you then need to get one from a Citroen dealer!

[oscar]

Also check for bubbles in header tank as might be pressurizing(daft spell checker)if there is a slight blow on head gasket which i had on mine but only had any effect at high speed