Engine Temperature question...

Hotter is better. My '89 termperature gauge reaches ~3 mm to the right of the over heating light.

Do you mean that the needle goes past the middle or never gets to the middle?

That could indicate that the thermostat in the water housing is stuck open. Or maybe stuck closed because you never said whether it is indicating hotter or colder. It should be the same as when it was new. Where it ran when it was new is the idea temp. Colder and the engine will be more polluting which is bad for your oil and mileage. Hotter and the engine does not like it either and is bad on the oil.

The eng>I have a 1992 VW Jetta EcoDiesel. For the longest time the temperature guage

Jim B.

Not sure exactly what you are describing (where is the guage when without ideling it and where is it after you let it idle?) but it does sound like a thermostat.

NO! it is better for the car to run at the design temperature. That is the job of the colling system. Too hot or too cold are both bad.

You want it to run as designed, make sure cooling system is working as designed.

Well that is its only job controling engine temperature.

Not likely. Unless you have special problems, the built in cooling is just fine. A good oil cooler would not hurt, but not all of them are good and many are junk. I would guess at least as many engines have been destroyed by a junk oil cooler as have had their life extended.

Don't look for modifications that may defeat all the engineering that went into your car.

No. If it were, there wouldn't be a thermostat in it.

If it runs too cool, carbon will build up in your engine.

Don't.

Absolutely. The thermostat opens and closes to regulate coolant flow through the radiator. When the engine is cold, it stays closed to keep coolant from flowing through the radiator. This causes the engine to warm up faster. When it warms up and reaches the specified temperature that the thermostat is designed to open at, it'll open and allow coolant to flow thru the radiator so the coolant (and engine) temperature doesn't continue to rise.

Basically, engines are designed to run in a certain temperature range. Excessive heat will damage it of course, but in the designed range it's fine. Cooler isn't always better. Your emissions will also probably be higher with a cooler engine as well as carbon buildup.

I admittedly don't know much about diesels but I think I heard they tend to run cooler (compared to gas engine counterparts). I don't think I'd bother on a diesel.

life at least 2 more years if possible!!! Does anyone have any other modifications that I should think about?

VW diesels are pretty tough. How many miles on it? You should see at least