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Both thermostats for the saab are marketed as genuine saab by eeuroparts, not walbro or anything. Therefore saab itself makes these two parts. I have heard that lower thermostats are used in hot climates like deserts. HOwever, if thermostat doesn't increse the efficiency of the cooling system, it shouldn't matter.

Maybe it could be something like the fact that with lower thermostat the cooling fan would turn on less often prolonging its life?

Klim
 

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Posted by mulik51: Maybe it could be something like the fact that with lower thermostat the cooling fan would turn on less often prolonging its life?
..or maybe it would reduce the tendency of the motor oil to coke up in the turbo cooling gallery when the engine is turned off?
 

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I,m just guessing but it wouldn,t surprise me if the diffrent thermostate ratings are for diffrent fuel spec relative to location = good = optimise performance and efficiency

or for diffrent emmission,s regulations = maybe not so good, its to pass a test
 

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It is difficult to see how a cooler thermostat can make any difference in a hot climate. If the ambient temperatures are 30C to 45C in the desert it should make no difference to the cooling system running at 90C whether the thermostat opens at 82 or 89C. Still, most manufacturers spec a cooler thermostat for tropical or desert conditions.
 

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Because in desert/tropical climates, an engine under heavy load (ie. climbing a 6% or steeper grade at speeds too low to provide much radiator airflow with the A/C on.) can produce more heat that it can dissipate through the radiator. So it they give themselves a larger safety margin between operating temp and overheating. Most cars now are made with excess cooling capacities as well as dumbed down temp gauges so you never need a cooler thermostat or even know that the engine temp has risen 10 C.

The smaller the difference in temperature between the radiator and the air, the less efficiently a radiator can dissipate heat. Even in a climate of 40 C you have to remember that the AC is also kicking out a lot of heat, so the actual air passing over the radiator is quite a bit warmer than 40 C. This effect doubles if you have a turbo/intercooler system under load.
 

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Thirsty9000 said:
Because in desert/tropical climates, an engine under heavy load (ie. climbing a 6% or steeper grade at speeds too low to provide much radiator airflow with the A/C on.) can produce more heat that it can dissipate through the radiator. So it they give themselves a larger safety margin between operating temp and overheating. ...
How do you figure this? The thermostat sets the minimum operating temperature, not the maximum. The maximum, as Jim has stated in this thread and several others, is determined by the heat dissipation capability of the radiator. When airflow is not sufficient, the cooling fan is activated. If you're moving so slowly that there's insufficient airflow over the radiator, you're generating much less heat than climbing that same grade at 70 MPH.

My 82C thermostat (now replaced with 89C) didn't help one bit while climbing long, steep, 75 MPH grades in 100F weather last summer. The engine ran every bit as hot as with an 89C thermostat. But the 82C unit certainly takes longer to warm up, and runs much cooler in the fall/winter/spring.
 

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Simple thermodynamics. Heat will be dissipated faster from an object at a cooler ambient temp than at a high ambient temp. In a hotter climate it can't dissipate excess heat as efficiently as in a cooler climate. So they sometimes set the system to begin to shed heat sooner thus increasing cooling capacity. (note capacity, not efficiency) This is the reasoning behind the offering of the 82 C thermostat. While I agree that the stock 89 C unit SHOULD work fine in a hot climate. And in a properly maintained system does. My friends Aero with a 89 or 91 (don't recall exactly) runs same temp come hell or high water. My CSE is more than eager to run in the top 80% of the scale (with 82 thermostat, thermo-fan switch and rad fan with the low speed bypassed). And a new radiator has given it much more consistance. I'm going to switch back to the 89 units and see how it behaves in the heat of the summer with a new radiator.
 

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I have a '92 saab 9000 cse, the temp gauge most recently has been floating upwards toward the red line when I'm stopped in traffic. When I'm on the highway, it seems to be fine. You said you don't worry about your saab when this happens, why is this?
 

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Here's the deal.

The saab temp gauge shows ACTUAL temperature of the engine coolant. A lot of newer cars will only show a relative coolant temperature. A lot of times in the old days, people would bring their cars in complaining of over-heating because they would see that the gauge was getting close to the red. In reality, in newer cars, they don't necessarily stay at at the same temperature all the time, but they made it so it didn't go so high as to not freak out car owners. They only went into the red when there was a real issue.

A little confusing, but does that help?
 

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I have been worried because I am not hearing my fan when it is running and the temp gauge has been running near the top all the time. I have been leaving the heat on because I was afraid it would over heat, thus the temp gauge stays in the middle, it sounds like I should stop doing this and see what happens. I assume that if I drive without the heat on, I will be much more comfortable, the fan will start and my fears will be unfounded. If it doesn't start and the temp goes to the red then I have a problem, but I may not be letting it go hot enough for the fan to start?
 

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I have been worried because I am not hearing my fan when it is running and the temp gauge has been running near the top all the time. I have been leaving the heat on because I was afraid it would over heat, thus the temp gauge stays in the middle, it sounds like I should stop doing this and see what happens. I assume that if I drive without the heat on, I will be much more comfortable, the fan will start and my fears will be unfounded. If it doesn't start and the temp goes to the red then I have a problem, but I may not be letting it go hot enough for the fan to start?
Just let the car idle for 20 minutes with the heat off. If the fan doesn't kick in, you know have a problem. It's very unlikely that you can do any damage to your engine this way. If the fan does kick in, you know your car is just fine.
 

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So. Tomorrow AM, I am taking delivery of a 1997 9000 Aero in absolutely beautiful condition.

But, when I took it for a test drive, the temp. gauge never got to that 9 o'clock position that I would expect at normal operating temperature. The highest it got was between 8 - and 8:30. Is this a known issue with 9000s? Is it likely just the gauge? Or - is it really not getting hot enough? How can I find out?

Thanks -
 

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These later cars do not display the actual engine temperature.

Having said that I would simply install a brand new SAAB spec 89C thermostat as a precaution.

Low temperature readings on that gauge are usually a result of a thermostat failing to close cmpletely when the engine is cold.
 

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Yes, you will lose coolant, a little. It is not a tough job at all. If you haven't done much car stuff it is still not tough.

Just read up on here, there are threads on it here. I even posted some photos.

When you put the new thermostat in make sure the little hole is to the top. I never used to worry about it but someone on here told me that is the right way to do it. Something about air trapping and needing to bleed out.

About where the needle is sitting, don't worry about it right now.

If I was you I would replace my thermostat anyway unless it has been done recently. There may be nothing wrong with it though and even with a new one the needle might sit where it does now.

Having said that one of my cars sits at 9.00 the other sits and 9.00 and a little higher at times. They both have new thermostats in them.

And enjoy your car, that is the model I am after. I have to put up with a 93 9000 2.3 griffin!
 

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Thanks very much. I'll look for your pix on the procedure. I suppose I should get a T-Stat right from Saab.

By the way - I love this car!
 

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I got genuine SAAB T/stats, not expensive, even here in NZ.
 
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