Why have a thermostat???

Why should there be a thermostat in the car?
Wouldn´t it be better to take more time at low temperature?

Marcello:

There shold be only one thermostat on your car, the one in the right rear fender well, in front of the oil tank, and which is an oil thrmostat, not a water thermostat. It is there to send oil to the oil cooler in the right front wheel well, when the temperature of the car has climbed to more that 215 degrees F. When it opens, I can usually hear the oil gurgling (how's that for a technical term?) as it passes through the pipes at idle.

The oil cooler on the motor is cooled by air which is directed from the fan on top of the block, which also cools the fins on the cylinders.

Does this help?.......Andras

One reason there is a thermostat for an external cooler is that when the engine start cold there is the potential to blow the cooler. Another reason is there is an optimal oil temperature for these vehicles lower oil temperature is not always best.

Andras,
There is also a oil thermostat mounted on top of the engine behind the injection system next to the oil pressure sender, right?
It controls oil flow into the engine mounted oil cooler doesn't it...


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Leland Pate

___79 SC Targa

So if the motor runs, lets say, bellow 80°c for a long time, this could damage the motor?

There is a graph that is oil temp VS something,I forget. I'll look it up latter unless Warren chimes in before then.

There is a thermostat mounted in the case right above the case mounted oil cooler. On cars equiped with an external cooler there is another thermostat controling the flow when needed.

The internal combustion engine must run at pre-defined temps. If you run an engine to cold it will wear out quickly, and you will notice low performance.

Mocal co.(oil coolers and oil thermostats)says "...thermostats are designed to prevent the flow of engine oil through the cooler until the desired temperature is reached. prolonged use of engines in conditions that oil cannot reach optimum working temperatures will cause sludge formation and crankcase oil diluation, leading to excessive wear Especially in the cylinder bores. Thermostats combat this by regulating oil flow to accelerate warm up. this in turn reduces drag, helping to yield optimum engine effiency and performance"
Bob W.

[This message has been edited by Bob W. (edited 07-07-2000).]

Ok, everybody is concerned if ther thermostat god stuck at the close position. What about if it get stuck in the open position, how do u tell? And how long does it take for the engine to warm 80°c at normal conditions?

Good question...
I'd say you could tell if your Aux. thermostat was stuck open by touching, feeling, and listening to your trombone/fender mounted oil cooler at start up. I know that on my car I can tell when it opens because I can hear and feel the oil running through the lines (plus it's real HOT). I'm not sure about checking the engine mounted oil thermostat.

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Leland Pate

___79 SC Targa

A thermostat stuck "open" could blow the engine mounted cooler (first) when started on a cold day when the oil is thick. In hot weather this may not occur, but the engine would come to temperature slowly. This is not good on moving parts and robbs power.

tks for the answers.

And how long would a 2.7l CIS take to warm up to 80°c in normal city driving?

Mine takes at least 10 mins of city or highway driving below 3500-4000rpm (which I won't exceed until it is warmed up)

About 3-4km (2-3 miles), I think.

That is in weather from 60-80 degrees (we don't get an awful lot of variation).

Cam

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Cameron Baudinet
1975 911S