Overheating=(

How far up is the temperature gauge ?

Mine sits below 1/2 way up during light driving. Climbing a long hill is enough to increase the temp. It gets hottest in stationary traffic.

Graham

How old? Year?

Does the cap fit properly on the expansion tank? Does it have antifreeze in the coolant (what is the dilution)?

If the car is old it can happen because the radiator is clogged up with rust from the engine block and salts from the water. I had to replace a radiator on my old c900 just because it was so clogged up.

Charles

one time it was near the red mark =o i will take out the radiator out how do i check it ?

will it hurt the car if i take out the thermostat

could it be the water pump?

I'd put thermostat suspect #1. Water pump is less likely as there is no leak but can't rule it out either. When was the last time you flush the radiator. Faulty sensors is also possible. Do it one at a time.

what do i look for in the radiator

and while i'm doing that should i clean out the intercooler ?

could it be that temp gage is out of wak

I'm afraid it could be any of those things.

Taking out the thermostat *might* be a bad idea. I think it's impossible to get to normally so don't bother ! ;-)

I'll suggest eliminating the water pump since I had a leak from a bearing on mine and all it did was to lose coolant slowly.

What colour is the coolant in the header tank ? Is it cloudy ? When did you last change the coolant ?

When was the cooling system last flushed ?

I do assume you have an approved additive to the water !

Graham

Well..... you can't actually see inside it so.......

If you happen to remove it - you should 'reverse flush' it with clean water from a hose or similar.

The intercooler is unrelated to the engine cooling system.

Not likely. Esp if the fan is running a lot.

Graham

in article snipped-for-privacy@f14g2000cwb.googlegroups.com, es at snipped-for-privacy@yahoo.com wrote on 09/06/2005 22:09:

Have the cooling system pressure tested. That will determine if there are blockages in the system. Also, what's the state of your radiator?

Paul

1989 900 Turbo S

Best way to check what might be going on it look at the fluid and see if it's contaminated and cloudy which indicates solids and other material has been picked up by the fluid.

You might also want to try flushing the entire coolant system and replacing the coolant with fresh fluid made from a quality coolant. I've recently been investigating this for my C900's and did a full coolant system flush when I decided to replace a broken heater control valve. The radiator drain plug hole was clogged with material that after I fully removed the drain plug (the car was cold!) no liquid came out!

If you check my Saab C900 heater valve replacement page at "

" you'll read about what Idid to 'pressure-clear' the radiator drain plug hole. 8-)

Do you mean that you want to 'take it out' as in remove it completely? or to check it's operation against a known good replacement?

When the car is running, does the fluid in the expansion tank get hot along with the fluid in the hoses to/from the tank? If it does (you can tell by the heat coming from the hoses and the tank), it's probably not the water pump.

Does the coolant system leak anywhere? Are you contantly topping up the coolant? What is in the coolant system? The car that I did the coolant system flush on didn't have any coolant in the water - it appeared to be plain water with nothing else. No wonder the bottom of the radiator was clogged when I took out the drain plug!

Regards,

Craig.

I have read all of the responses you have received thus far and nobody has given you the correct advice yet. The key to diagnosing your problem is something you stated above: "overheats in traffic not on the highway."

Think carefully about that statement. What this is telling you is that, when the engine heat load is the highest (at highway speeds) the temperature is normal, but when sitting still and idling (lower heat load) the engine temperature climbs.

Those symptoms indicate that the majority of your cooling system (radiator, water pump and thermostat) is relatively healthy. It will do its job if you get enough cold air flowing through the radiator. You also stated that the fan is running. 9000s have two speed fans which are thermostatically controlled. When the radiator temperature gets above a certain point (or if the AC is on) you should hear the fan's high speed kick in. Without the high speed the engine temperature will climb in summer's heat.

The original set points on the thermostatic fan switches were too high (92C) IMO. Switches with lower set point (82C) can and should be bought. I would combine that switch upgrade with a lower temperature (82C vs

92C) thermostat. And no, you should never just remove the t-stat. They are not that hard to get to and change, and also a cooling system flush/fill with SAAB (blue stuff) coolant.

Go to this web site and read up on the cooling systems info in the technical documents. There is wealth of information here. Do not allow your SAAB engine to overheat again or you will very likely get to replace the head gasket. (much less fun)

I've owned 2 9000's, (still have one) both of which exhibited cooling system problems such as yours and worse. In both cases, after upgrading the switch and thermostat to lower temp units and flushing / filling with blue stuff, they have run many trouble free miles.

-Fred W

What he said.

i only hear my high speed fan when the ac is on

are you talking about the aux fan switch that is on the bottom left side of the raydiator??

See below.

Pass. Can't comment.

No. The gauge does not relate to anything. If the electric fun comes on, the coolant is getting warm/hot. It does not matter what the gauge shows.

As Pooh Bear said reverse flush it. (Getting thinking cup, on hot water goes in at the top colder water comes out the bottom) you need to feed water at the bottom hole. If you take the radiator out then turn upside down and feed as much water under pressure as you can.

There is a good likelyhood that if you reverse flush the radiator and do it well :-) it will develop a leak or two. If that happens and given the problems you have then look for a replacement radiator.

After you reverse flush the car etc, you must run it stationary for a while to see if any leaks develop (if they do then you also know that it was salts and rust that were holding it together).

You could remove the thermostat completely (it is necessary for winter). However do one thing at a time and DO NOT let the car get near the red line. Danger of getting a blown gasket and definitely a warped head.

================= Having said all that, the fun on my car comes on in the heatwave temperatures we get in the UK (like 68 F if lucky). BUT the needle never rises above half way.

If it helps at all. Charles

in article snipped-for-privacy@g44g2000cwa.googlegroups.com, es at snipped-for-privacy@yahoo.com wrote on 10/06/2005 03:11:

Cold spots. When the car is warm and the thermostat has opened, taking care to avoid running fans, place your hand on various parts of the radiator to determine if there is an even spread of heat. Cold spots indicate blockages and therefore inefficient cooling.

Might as well ... Just squeeze off a couple of canisters of carburettor cleaner through the intercooler and leave to drain. Do the throttle intake too. On the 9000, remove the intercooler and spray half a can into both sides, then invert and spray again. Leave to drain. Refresh jubilee clips upon re-fitting.

I'm pretty sure the 9000 uses the same principle as the C900, in that a temperature probe is screwed into the block (and therefore grounded) and a resistance controlled positive feed goes to the gauge. Unless the gauge registers zero, it's working. You could always change the sender, which will probably only be, maybe, 10 quid, euros, whatever, from you nearest dealer.

Paul

1989 900 Turbo S

I will pass no comment on the two speed switch as I did not know that the 9000 had such a thing. Learn something new every day.

That aside, and given the same observations you make, I am afraid, if the car last year run normally and this year (summer) it does not AND if the switch is in the same condition as the year before it only leaves the radiator being clogged up. Till I got the car I did get, every 9000 I saw (post 1993 models) had the expansion tank discoloured by rust. As you say below ... does the car have the right coolant. Has it *always* had the correct coolant or did the block get rusty?

But it will be a lot cheaper to replace the thermostat/switches as you suggest than to replace the radiator :-)

Regards Charles

MODIFICATION TO ALLOW AC FAN AND COOLING FAN TO RUN AT SAME TIME!

This is the bulletin that shows how to modify the relay circuitry to enable the A/C cooling fan at the same time the radiator cooling fan is actuated. This modification along with changing the coolant temp. sensor and the thermostat allow the engine to run cooler

hear is the link for it

how do i do this?????????

---8

I'm familiar with the scene he's described; mine, though, runs hot(ter) now at high speed. It's still at around 3/4s on the gauge, however. How's that? Now when it's cool outside, it has run at around 1/4. I do have the fan switch and thermostat you alluded to installed, too! (and not the blue coolant, since I intend to replace two heater hoses first...)..

es,

1st off, since you seem to be becoming a regular poster, please try and remember to quote just a tad of the post that you are replying to so we can all see what you are trying to say....

Now that I see that you are replying to me, yes, the high speed fan on your car may *never* come on if you have the original temp switch installed. This is the brass looking affair the is screwed into the lower right side of the radiator (note: left and right side are *always* quoted in reference to the driver's viewpoint, never the mechanic's).

plese refer to my prior post for a link to the Townsend web site that has oodles of info on this SAAB peculiarity.

-Fred W