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Discussion Starter · #1 ·
Hi folks,
I'm a first time Saab owner.**First car I've ever bought in fact, so bear with me...
Sitting in traffic Saturday night.
Temp gauge is about at half way mark.
Suddenly lots of steam coming up out of hood.
Shut the car off, pop the hood.
Seems like there is lots of steam and whistling coming from coolant tank.
Most of not all of coolant is on the street directly below car.
I let the car cool way down, then put a gallon of distilled water in coolant tank and drive her home.
The car has ran perfect since this has happened and the coolant has not leaked a drop.

Any ideas what happened?**I'm having things checked out and the coolant flushed.**Is there anything else I should be aware of?

I appreciate any input!
 

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Unfortunately you did not know of the "high mileage used car" PDI. This incident could have been averted..
PDI is pre-delivery inspection, sometimes performed on brand new cars. This should include the education of the prospective buyer...

100% of the vehicle is gone over 100%. The history is vital, as is the quality of previous work...
The coolant is still "leaking" - apparently very slowly as it is wont to do..An inspection with a pressure test will expose the "leak"..
 

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Th pressure relief valve may have opened. It could be a defective valve, or the system overheated. The temp gauge on the instrument panel is controlled by the ICE, and does not react very quickly.

I would check the electric fan. While driving, air flows over the radiator from the motion of the car. When you stop in traffic after driving, the fan does the same job. If the fan does not run for some reason, the coolant temperature rises very quickly.

Radiator Fan
 

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I'll bet my membership on this forum that the low-speed fan resistor is dead.
If you need one, I have a couple kicking around. I think they're like $10 each.
 

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Hi H4N5 also test the thermostat it could be faulty , or it could have been that the coolant tanks lid was loose/cross treaded and let go at operation temp .
Cheers.
 

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Discussion Starter · #6 ·
The Saga Continues...

Per the gracious advice of those who responded, I had the ol' PID done.
A pressure check revealed there was a small hole in the radiator.
I also had asked them to double check the fans were in working order.
I picked the car up on Friday.
The dealer assured me everything was good to go**(hitting the road to visit family...700miles away Monday morning.) and that to make sure, he let the car run "all day long" just to make sure it wouldn't over heat again.

Which brings us to this evening.**Sitting in traffic in Queens doing my holiday shopping when from the hood comes spewing, steaming coolant.
AGAIN.

This time I'm able to jump out and open the hood.

It appears to be coming from the coolant tank, a whistling from the cap it seems like.**
The cap was screwed on very tightly and I don't believe it's been cross threaded.

What you think folks?**Cap?**Why did it over heat in the first place?

Man, I don't want to miss Christmas...
 

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Well, for what it's worth, it's much less likely to overheat on the highway than sitting in traffic....
As far as I know there's a pressure release valve in the coolant resevoir cap, mine usually hisses (fairly quietly) for a while after the cars switched off as it cools, I really haven't thought anything of it though.
I'm assuming the hole was fixed and fan's definetely going now?

Andrew
 

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The dealer may not know much of the car that he sells; but I doubt if Saab is the only one using resistors to control the fan... In other words automotive mechanics are extremely complex, much more so that in the 60s.

I fully agree with PMI on this ICE(integrated central electronics) controlled temperature gauge , the driver must know if overheating is occurring ASAP if not sooner..
And "sooner" is only possible with a high level of knowledge of automotive mechanics and the ability to implement them...

If this happens again (overheating), turn on the AC, this will cause the high speed fan to run (if that works)... back to the PDI(pre delivery inspection) again..
Also, turn on the heater if overheating begins, even in the summer...
And that cap must not be that tight on the reservoir, this is damaging of the threads and the seal...
Over-tightening - what a problem:nono;
 

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Well, what's probably happening is basically this, the engine heats up normally while driving, and as long as it is cooled from the air passing over the radiator, everything is fine.

When the car stops in traffic after being driven at normal speed, the engine is still hot, and the electric fan normally takes over and runs to cool the radiator. Seems like that is not happening, and the coolant boils over and escapes through the relief valve in the cap.

If the same thing does not happen at idle, it is because the engine does not get hot enough. So you can idle the engine all you want, it will not prove anything.

As for why this is happening, the fan was my guess, because mine failed. There may be another scenario that can make this happen, which I am not aware of.
 

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Discussion Starter · #10 ·
Bingo!

Brilliant!
I had asked the mechanic specifically to check the fan. He assured me the entire system was checked over.:x

Right now, I'm almost 100% sure the fan is not kicking on.
PMI, I think you hit the nail squarely on the head.

I appreciate everyone's input very much!
 

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Discussion Starter · #11 ·
Stealership checked it out today...
Cooling fan it is. However, they want to replace the entire fan system.
I'm hoping it's just the resister as G96NT had suggested.
Any way to check that out?
 

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H4N5 said:
Stealership checked it out today...
Cooling fan it is. However, they want to replace the entire fan system.This will give them the most profit in the least time.
I'm hoping it's just the resister as G96NT had suggested.I am almost positive it is...
Any way to check that out?
DIY, examine, test, measure the resistors resistance..This design can be improved ; Resistance = heat (common knowledge) then the heat destroys the wire insulation, now shorts can happen.....
Thanks to this site, and PMI, I discovered this situation on my own car and I had to spend some time and trouble repairing this area..

Maybe a really good indie can do this; NOT the dealer, unfortunately:nono;

http://www.geocities.com/[email protected]/NG900SET/Rad_fan/fan_test.html?200717
Hope this helps:cheesy:
 

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If you can't get the resistor from G96nt, send me a message. I have a couple extra too.

If you do not want to go that route, you can usually get the fan from a salvage yard for $50-$100.

You are lucky it happened in the winter. It is a common problem, and unfortunately, in the summer it can lead to overheating the A/C, leaks, and expensive A/C issues.

The low fan speed is used to cool the A/C condenser, which sits in front of the radiator. if the condenser overheats, the pressure in the system goes up. Eventually an overpressure switch trips the A/C off, but over time, the excess pressure can make the system leak (mine did).
 

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As a "meantime" fix, just leave the a/c on, even if it's on warm. It kicks the high fans on every 30-45 seconds and keeps the temp down. (this is likely what your mechanic did, when he left it running all day... he just started it, and left the ACC on.)

You can ALSO jump the high fan relay under the hood with an 8-ish guage wire so the fan's on with the Car in a pinch (I had to do this, once)

when I replaced the resistor, I soldered on about 6-8" of wire on each end so I could do it easily, without muscle-ing around down by the fans/turbo/IC blah blah blah. now, the resistor is in the path of the air blown by the fan, so it doesn't get NEARLY as hot, and will last "forever".
 

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G96nt said:
As a "meantime" fix, just leave the a/c on, even if it's on warm. It kicks the high fans on every 30-45 seconds...
I believe the ICE module may use the low fan speed for the A/C. I will double check that later, but that is my recollection. That is why the A/C overheats if the resistor is burned out, and the fan does not cool the condenser.

Leaving the fan on high constantly has been tried. The fan motor eventually overheats and burns out when run all the time. That may be why we have low and high fan speeds in the first place.
 

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"we" have a single fan with "default" being high-speed, and A resistor to lower voltage to create a lower speed... "low" fan.
 

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G96nt said:
"we" have a single fan with "default" being high-speed, and A resistor to lower voltage to create a lower speed... "low" fan.
Do you have a copy of the WIS handy? (mine's at home). I don't remember it that way, meaning "high" the default, but I could easily be wrong... :confused:

I documented what I do know, at the links below, but if you have some additional info on the fan, please post it.

Fan op. & testing

Res. Replacement

The temps at which the fan turns on are consistent with what can be found in the WIS. The resistor I used is a high-temp part with an integral aluminum heat sink w. fins, about $3-4 from a distributor. The wiring, solder and crimp joints I show in the pics are by someone who makes custom wiring kits.

For anyone else, also note that Saab used to supply a similar kit for the 9K model which had the same fan setup, and same failures, years before the first NG 900 rolled off the assembly line. Very common w. 9K owners, and documented in a Saab TSB for the 9K.
 
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