Running hot

Assuming there is water/coolant in the radiator/overflow tank, it probably needs a new thermostat. Check the records to see if it was replaced recently. It may be an easy do-it-yourself job, depending on how much you've got to remove to get to it.

snipped-for-privacy@madmousergraphics.com

miles, one previous owner (now deceased). >Dealer checked it out, said everything is working fine. >And it seems to be, except it runs hot, often time right >up to the redline. Is this a normal thing for this car? >What else should I watch for? I understand regular >service is essential, and from the records that came with >the car that has been done.

probably needs a new thermostat. Check the >records to see if it was replaced recently.

to remove to get to it.

miles, one previous owner (now deceased). >Dealer checked it out, said everything is working fine. >And it seems to be, except it runs hot, often time right >up to the redline. Is this a normal thing for this car? >What else should I watch for? I understand regular >service is essential, and from the records that came with >the car that has been done.

probably needs a new thermostat. Check the >records to see if it was replaced recently.

to remove to get to it.

As others have said, the thermostat is the most likely cause. However, it is useful to determine when it overheats. Is it when you are sitting in traffic, or when you are using the engine hard (e.g. on the motorway etc.)?

If it overheats most when you are sitting in traffic, then it could be that the fan is not cutting in. This could be because the fan motor has failed, or the fan thermo switch has failed.

Yep, what everyone else says.

Make sure the stat fitted (and the one you replace it with) is the correct temp range, and a genuine Saab 3 stage one, 1)closed, 2) open with heater 3) open without heater.

Also before replacing the rad fan or thermo switch, disconnect the switch, and touch the terminals together with a piece of wire, and see if the fan runs, then change try cleaning the terminals on the switch, reckon ect the wires, and run the car upto temp make sure it switches out.

Andy creamy mess in the oil, or oily skum in the coolant?

One more hot tip for you:

FIX THIS IMMEDIATELY! That thing continues to run hot or overheats and you might end up looking at a head gasket job! I certainly do not like the sound of "often time right up to the redline" ! Over repeated hot operations the head could possibly warp.....

If it turns out that the thermostat, thermostatic fan switch, and fans are all working then change the radiator. Overtime they tend to get clogged and not allow efficient circulation/cooling.

Unless the radiator is leaking, flushing it through usually fixes the problem. Garden hose, home-made adaptor, 20mins on high flow.

Also might want to check that the radiator fans are working properly, and that the radiator fan temperature sensor is working. I used to have a similar hot-running problem, which went away with replacement of a faulty radiator fan.

John

Wow! Thanks for all the responses!! I will print them out for my mechanic and let y'all know what happens.

Have a swell weekend, and thanks again.

Dick

If you have to print out those "basic" things to check for your mechanic.....maybe now is a good time to change your mechanic.

First, most logical, easiest to do, and cheapest thing to replace is the thermostat.

Dave "Now to read 17 messages telling you the same thing" Hinz

Well, no, it's actually for me to remember to ask the mechanic. We are wrench-challenged here. I just drive 'em, I don't fix 'em.

I had to replace the radiator on my 1987 900 due to running hot also. Tried all the other stuff, flush, t'stat tigthen belts but the final fix was a replacment Radiator.

Have Fun, Oscar

That would be a bit of an issue here (Sydney, Australia) with our water usage restrictions, unless all the used water was being collected for recycling into the garden (assuming the work isn't done with the car on a flat section of the yard with grass all around). 8-)

We can't wash cars with a hose at the moment - only from buckets. And we can only water the garden (with hand-held hoses) on certain days of the week. Sydney's total water supply is still well under 50 percent of 'full' capacity (check the specs at "

On the subject of radiators, are there different types for Saab's? There's a few people selling new radiators for 900's on Ebay, and in a 4x4 mag here there is a place that makes special high-performance radiators for off-road vehicles and many on-road vehicles that cost about double what a conventional radiator for a specific make/model costs. I think the special radiators are double-circulation units and/or made from different materials (copper?) to aid thermal flow.

Regards,

Craig.

An interesting observation with my two C900's (1982/83 and 1985). With the

The left-hand fan in the 1982/83 car only turns on when the air-conditioner in operation (haven't worked out if it runs continuously when the A/C is on as yet, or if it's controlled with a thermo-switch). Is that indicative of a problem with the older of the two cars, or is it a design difference that's represented by different wiring of the fan circuits?

When I get the chance I'll try to trace the wiring for each in the circuit diagrams printed in the Bentley manual but I'll need to be well-rested to make sure I can trace the circuit paths on the small-scaled diagrams properly. 8-)

Regards,

Craig.

I assume you know about watering at dusk, to reduce evaporative losses? In the UK, where temperatures rarely rise to anywhere near those in *.AU, farmers reckon on _halving_ spraying losses in summer. You also avoid problems of water droplets on leaves refracting intense sunlight and causing burning (which one hears can be a problem with some species).

Daft thought: does an unwashed car keep out the heat better? A decent coating of low thermal conductivity dust and mud, ideally a nice pale colour, sounds promising.

-- Andrew Stephenson

Obviously, yes. You will not be able to fit a 900 radiator in a 93, though the 99 and Sonett III radiators are the same. I know that for my 95/96 I have the choice of a two or three channel core, the latter is slightly thicker but can still be fitted and has a higher cooling capacity. These rads are made from the old radiator by soldering a new core to the old header tanks.

Newer radiators are made of aluminium/aluminum, that has a better heat transfer than copper, with plastic header tanks.

-- MH '72 97 '77 96 '78 95 '79 96 '87 900T8