[91900turbo]

Greetings:

My car has never overheated, however it has been getting fairly warm-hot. The guage has always ventured up to about 2/3 to 3/4 of the way near the "HOT" marker ! However the engine has never overheated? Both fans would cycle in an attempt to cool it down. The cycle rate would usually last about 90-120 seconds or so. The temperature would slowly begin to drop very soon thereafter. This all usually occurs when I am in traffic and or have just exited off the hwy, and stopped at a traffic light ilding. But when I travel on the hwy, which is 99% of the time, at average speeds of 75-85 mph, the engine temp guage remain in the middle. I figured it couldn't be much of a clog somewhere in the system, simply because the heat that comes through the vents has been very warm-nice and toasty, to somewhat very very warm-hot! I was wondering whether it might be in fact my water pump? Whereas it could be a circulation issues at low speeds? And at hwy speeds, of course the circulation would be at a might higher rate? What say you? Also, what is the best pump for the money? A part from eeuroparts.com or a pump from Advance auto parts (ASC NEW PUMP)?


Best Regards,

1991 900 turbo 16 valve 2.0 A.T. 175,000 original

 

[c900]

Greetings:

My car has never overheated, however it has been getting fairly warm-hot. The guage has always ventured up to about 2/3 to 3/4 of the way near the "HOT" marker ! However the engine has never overheated? Both fans would cycle in an attempt to cool it down. The cycle rate would usually last about 90-120 seconds or so. The temperature would slowly begin to drop very soon thereafter. This all usually occurs when I am in traffic and or have just exited off the hwy, and stopped at a traffic light ilding. But when I travel on the hwy, which is 99% of the time, at average speeds of 75-85 mph, the engine temp guage remain in the middle. I figured it couldn't be much of a clog somewhere in the system, simply because the heat that comes through the vents has been very warm-nice and toasty, to somewhat very very warm-hot! I was wondering whether it might be in fact my water pump? Whereas it could be a circulation issues at low speeds? And at hwy speeds, of course the circulation would be at a might higher rate? What say you? Also, what is the best pump for the money? A part from eeuroparts.com or a pump from Advance auto parts (ASC NEW PUMP)?

Two things come to mind - if the air vents are always blowing warm to hot air, perhaps your car's heater control valve is not working correctly.

As for the overheating (if the temp gauge goes anywhere near 3/4 or higher, it's overheating in my book!) issue, take the car to a good local radiator service place and get them to give the cooling system and radiator a complete check. If they say the radiator is fine (and it isn't blocked and/or contaminated with significant sludge), you can look at other things like the water pump.

Craig.

 

[TooMany2cvs]

My car has never overheated, however it has been getting fairly warm-hot. The guage has always ventured up to about 2/3 to 3/4 of the way near the "HOT" marker ! However the engine has never overheated? Both fans would cycle in an attempt to cool it down. The cycle rate would usually last about 90-120 seconds or so. The temperature would slowly begin to drop very soon thereafter. This all usually occurs when I am in traffic and or have just exited off the hwy, and stopped at a traffic light ilding. But when I travel on the hwy, which is 99% of the time, at average speeds of 75-85 mph, the engine temp guage remain in the middle. I figured it couldn't be much of a clog somewhere in the system, simply because the heat that comes through the vents has been very warm-nice and toasty, to somewhat very very warm-hot! I was wondering whether it might be in fact my water pump? Whereas it could be a circulation issues at low speeds? And at hwy speeds, of course the circulation would be at a might higher rate? What say you? Also, what is the best pump for the money? A part from eeuroparts.com or a pump from Advance auto parts (ASC NEW PUMP)?

Unlikely to be the pump.

The pump's either turning & pumping or it isn't - in which case, it's the belt gone. The failure mode is usually leaking from the seals.

Sounds far more like the rad to me.

 

[91900turbo]

Unlikely to be the pump.

The pump's either turning & pumping or it isn't - in which case, it's the belt gone. The failure mode is usually leaking from the seals.

Sounds far more like the rad to me.

Ironically the previous owner (original for the last 16 years), has a radiator that looks like it came from another Saab or something? I have these cooler like ports for the transmission, but they are not in use. The car has its own seperate tranny cooler, in addition to the engine oil cooler. I was going to replace the radiator just the same. Should I opt for the Nissen brand or what. I believe eeuroparts.com sells them? I should be safe for the moment, because the car doesn't reach the "HOT" marker and my driving is mostly all hwy. It tends to get somewhat warm about 50% of the time. I haven't noticed any oil to be burning, and or any coolant levels boiling and or evaporating, plus the motor hasn't been knocking and or shaking like a over heating engine usually does. I just know that should it spike to the hot zone, I am pulling over and slowly idling the engine to help in cool it down, otherwise I would eventually sut the motor off. Is the radiator a real pita to remove/install? It looks to be moderately easy to tend to, however, what say you, please all of your suggestions/experiences would be greatly appreciated! And thanks to all who responded and continue to respond. This is my first Saab, and second turbo. Nice car!


Best Regards

 

[c900]

Ironically the previous owner (original for the last 16 years), has a radiator that looks like it came from another Saab or something? I have these cooler like ports for the transmission, but they are not in use. The car has its own seperate tranny cooler, in addition to the engine oil cooler. I was going to replace the radiator just the same. Should I opt for the Nissen brand or what. I believe eeuroparts.com sells them? I should be safe for the moment, because the car doesn't reach the "HOT" marker and my driving is mostly all hwy. It tends to get somewhat warm about 50% of the time. I haven't noticed any oil to be burning, and or any coolant levels boiling and or evaporating, plus the motor hasn't been knocking and or shaking like a over heating engine usually does. I just know that should it spike to the hot zone, I am pulling over and slowly idling the engine to help in cool it down, otherwise I would eventually sut the motor off. Is the radiator a real pita to remove/install? It looks to be moderately easy to tend to, however, what say you, please all of your suggestions/experiences would be greatly appreciated! And thanks to all who responded and continue to respond. This is my first Saab, and second turbo. Nice car!


Best Regards

I would never use any other brand of radiator since Nissens are one of the few OEM producers who make radiators with fully copper/brass cores that do not have plastic 'tank' sections at the ends. A lot of cheap radiators are plastic on the ends.

Also if the car doesn't currently have the turbo-spec radiator (which I think is wider than the non-turbo spec one) try to get the turbo-spec one. A number of places on Ebay sell the genuine Nissens turbo-spec rads for classic 900's.

Craig.

 

[TooMany2cvs]

I was going to replace the radiator just the same.

I think I'd try flushing it through first - just disconnect the main hoses, and shove a hose pipe in there. You'd probably be astonished at what'll come out... It's also worth pulling the grille off the outside and having a look at the front - make sure it's not covered in carp, and that the fins aren't all corroded off.

Is the radiator a real pita to remove/install? It looks to be moderately easy to tend to

I've only done it on a non-turbo so far - so none of that pipework to shift - it wasn't difficult at all.

 

[91900turbo]

Thanks Craig, a turbo spec version from Nissen!

I would never use any other brand of radiator since Nissens are one of the few OEM producers who make radiators with fully copper/brass cores that do not have plastic 'tank' sections at the ends. A lot of cheap radiators are plastic on the ends.

Also if the car doesn't currently have the turbo-spec radiator (which I think is wider than the non-turbo spec one) try to get the turbo-spec one. A number of places on Ebay sell the genuine Nissens turbo-spec rads for classic 900's.

Craig.

 

[91900turbo]

Thanks ! I agree, however for the sake of aggravation, particuarly before the summer, I am going to eventually replace it. However, I will still flush the system before the real frigid weather starts up, which of course ain't too far off !

I think I'd try flushing it through first - just disconnect the main hoses, and shove a hose pipe in there. You'd probably be astonished at what'll come out... It's also worth pulling the grille off the outside and having a look at the front - make sure it's not covered in carp, and that the fins aren't all corroded off.



I've only done it on a non-turbo so far - so none of that pipework to shift - it wasn't difficult at all.

 

[Matthew]

From what you've described, I'd say that everything's functioning as it would do with a higher-temp thermostat (one of the 92 deg units) and and fan themo-switch.

If the rad was knackered then the engine temp would steadily rise when cruising on the highway. If the rad was knackered the engine temp wouldn't drop when the fans ran.

By all means replace the rad if the unit's original. Also replace the coolant if its history is known (use green/bluey stuff - not red) with a new thermostat and fan thermo-switch.

If you want the car to run cooler, then stick in an 82 deg unit and a cooler fan switch. Make sure you buy only a genuine Saab (made by Motorad) thermostat.

A visual inspection of the rad will tell you a lot. Look for leaks, corrosion or missing fins.

With the car upto full temperature (fans cycling), remove the front grille and run your hand over the surface of the radiator and check for cold spots. If there are any then the rad's partially blocked and should be replaced (flushing won't clear the blockages).

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[dasander]

Start with a new thermostat and coolent, then look at the radiator. I'd replace the radiator if it looks suspect.

 

[Matthew]

I'd start by inspecting the rad :lol: It's a free test and may tell you a lot.

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[91900turbo]

Thanks! Now would it be to my overall advantage to keep a cooler thermostat in my car year round (one of which being that its a turbo), or what? Is it safe to do so? What are your takes on the pros/cons of lower temp thermostats and radiator fan-thermo switches? I am definetely replacing the radiator, belts, hoses, and eventually the waterpump, before the summer of 2008. Right now the belts/hoses etc are visually ok and functional. Could I get the thermstat/switches from eeuroparts.com? Where do you suggest? Thanks again!

From what you've described, I'd say that everything's functioning as it would do with a higher-temp thermostat (one of the 92 deg units) and and fan themo-switch.

If the rad was knackered then the engine temp would steadily rise when cruising on the highway. If the rad was knackered the engine temp wouldn't drop when the fans ran.

By all means replace the rad if the unit's original. Also replace the coolant if its history is known (use green/bluey stuff - not red) with a new thermostat and fan thermo-switch.

If you want the car to run cooler, then stick in an 82 deg unit and a cooler fan switch. Make sure you buy only a genuine Saab (made by Motorad) thermostat.

A visual inspection of the rad will tell you a lot. Look for leaks, corrosion or missing fins.

With the car upto full temperature (fans cycling), remove the front grille and run your hand over the surface of the radiator and check for cold spots. If there are any then the rad's partially blocked and should be replaced (flushing won't clear the blockages).

 

[91900turbo]

Thanks! I think I am going to just replace it all.

Start with a new thermostat and coolent, then look at the radiator. I'd replace the radiator if it looks suspect.

 

[RickyS]

91900turbo
I would not replace anything. What you described in your 1st post sounds normal to me.

 

[Matthew]

I'm inclinded to agree with Ricky. If it ain't broke...

Inspect the rad and have a look at the thermostat to see if it's a genuine item.

On a 16v car, the thermostat can be removed with very little coolant loss. The engine must be stone cold (left overnight for instance). When the thermostat housing's removed, at most 1/4 litre of fluid will escape.

Upon refitting the old thermostat or a new one, the cooling system must be bled to get rid of trapped air (take a look at the FAQ for instructions).
http://www.saabcentral.com/forums/showthread.php?t=62123

I think I'd just enjoy driving it...

I have spent a lot of time and money fixing stuff that was never broken, in particular cooling system components. I now wish I'd spent my time fixing the stuff that actually was broken!

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[Albert Trout]

I'll threesy what Mathew & Ricky are saying. I think a lot of people get a bit freaked by the fact that the temp gauge swings about so much on our cars. I'm not sure how a lot of cars temp gauges work but I suspect that they only move above the middle if the car is close to serious overheating. I've heard the cooling fan cycle in traffic on a lot of cars that I've driven and yet the temp gauge hasn't moved a mm. Sitting in traffic waggling between 1/2 to 2/3 or 3/4 is perfectly normal IMO and trust me, I've had a lot of issues with my cooling system in the past

Ooh, and check your timing as well. You'd be surprised by how much hotter the car will run if you're a wee but retarded...

 

[philb]

As Albert has said, I think the c900's temp guage is a bit more truthful than that fitted to most modern cars.
Your car is NOT overheating, but I think 3/4 is a tiny bit on the hot side. It is normal for it to go to 2/3 or 5/8 on the guage. The thermoswitch for the fan can (apparently) degrade with age, so it might be worth changing that, and the thermostat. Give the radiator a good flush while you are at it, and fill it up with fresh coolant. Bleed it a few times. The end.

 

[TooMany2cvs]

It is normal for it to go to 2/3 or 5/8 on the guage.

Hmm. I'm not seeing anything like that.

Mine's sitting a good chunk around 40% in normal use, with the only time I've seen much over 1/2 being when I was towing somewhere north of a ton up the motorway and hit heavy traffic for an hour or so. Then it varied between about 50-55-60% with the fan.

The possibility of a hotter thermostat would make sense, though - not to mention normal variance between different temp senders & gauges.

Still reckon a good change of coolant and sluice out might make the world of difference, though.

 

[Albert Trout]

The thermoswitch for the fan can (apparently) degrade with age, so it might be worth changing that, and the thermostat

That's another thing I've had go wrong...the connectors to the thermoswitch can get pretty mucky over time. I'd recommend that anyone puts new spade connectors on there. Cooling fan not working in traffic jam = steamy visit to the hard shoulder

 

[philb]

2manycv's - 40% means your thermostat is too cold, or on the way out. If you are not in traffic, it should stick at 50%, rock solid.