overcooling - maintaining 60 degrees - HDI DW10

eurotrotter · Post by **eurotrotter** » 25 Apr 2011, 22:24

hi guys

i had an overheating issue, and i said id take out the thermostat

i took it out, screwed everything back together, and drove on, and noticed that the car dropped in temperature - it went from 90 degrees all the way to 60degrees, and stayed there- as i drove on teh autobahn the whole way.

when i got into the city areas, it heated up a little - to about 70 degrees, and when i went back on the autobahn it went back to 60degrees.

is this ok, or could it do damage to the engine maintaining 60 degrees, rather than 90 degrees, which is overheating territory on a hdi?

i was expecting the removal of the thermostat to cause the car to maintain the operating temp of around 78 degrees to be honest, so this 60 degrees business is strange for me

thanks for your help

ed

HDI · Post by **HDI** » 25 Apr 2011, 22:30

That is too low for normal running temperature. Don't forget also that the oil cooler on Hdi's is heat exchanged with the coolant so too low a coolant temp will also lower the oil temp. When winter comes it will run at an even lower temperature. It seems you must have a faulty thermostat so it would be best to replace it with a new one.

Post by **Peter.N.** » 25 Apr 2011, 22:57

Its about the effect you would expect with no thermostat, when you are driving at above say 30 mph you have a strong current of air through the radiator which slows as you do accounting for the rise in temperature.

If you had been driving it like that in December when we had sub zero temperatures I doubt if the temp gauge needle would have moved off the stop, I know it took about 5 miles for mine to and it has an auxiliary heater.

The purpose of the thermostat is to prevent the water flowing through the radiator until the engine has attained normal working temperature, which an Hdi rarely does in cold temperatures, it doesn't produce enough heat to maintain normal temperature when the heater is on full.

Your experiment has confirmed that the cooling system is OK so a faulty thermostat or temp gauge seem to be the problem.

Peter

Chlorate · Post by **Chlorate** » 26 Apr 2011, 01:30

Looks like putting a new thermostat in would solve your overheating problem then.

If you have your old 'stat and a thermometer handy, you could test it by dropping it in a pan of water on the hob and reading the temperature at which it opens and comparing it to the temperature stamped on it.

rmunns · Post by **rmunns** » 26 Apr 2011, 15:33

Chlorate - not just the temperature it opens at, but also how much it opens.

If you get a new 'stat, then suspend both old and new in a pot of water and heat up to see how they compare.........................