Where is the thermostat located on my 1999 SAAB 9-5 SE?

[bigdogmai]

My 1999 SAAB 9-5 SE is losing anti-freeze, but the temp gauge never spiked. I want to check the thermostat, but I do not know where it is located and the manual has been no help in this matter.

[mark h]

follow the radiator hose most run off the top hose into a housing, but if yours is a reverse flow it will be on the lower hose.the thermostat regulates the coolant flow so if that was bad it would either over heat or take longer to warm up.If you have a coolant leak turn the car on and check the hoses and underneath for fluid loss.You can take this in to a shop which i recommend.They will pressure test the system higher than its rated and that will help detect a leaks.Coolant in the oil or bad head gasket is very unlikely unless you highly neglected your engine.Reason being coolant is only under 16psi your pistons psi is far greater it would not be able to penetrate.

[saaber89]

How fast is it losing coolant? If it goes down very gradually you could have a head gasket issue as the early 9-5's with the 2.3t had some head-bolt stretching issues. Sometimes re-torquing them solves leaks. Like another answerer mentioned the coolant bypass valve is a VERY common failure on 9-5's. If you look behind the engine there's a valve zip-tied to the firewall with a vacuum hose on top of it, one hose going in, and two coming out on the opposite side. With heat on this thing will leak slowly if not any, but as soon as you put demand for A/C on the system that valve will turn into a full-coolant-reservoir-emptying-Niagra-Falls.
Here's what the valve looks like when it failed on my car:
http://good-times.webshots.com/photo/2258005980095290419HJVFHG?vhost=good-times
I have the V6 but the valve looks the same and is in the same place on the 4-cyl engine.
And here's a link to the whole album I made when I replaced mine.
http://good-times.webshots.com/album/567023354FEMHNi
It's a pretty simple Do It Yourself job and the part is about $60 if you shop around.
Thermostats on 9-5's rarely leak. They usually either get stuck open or closed leading to the need to replace them.

[Funzzy]

Again, folks need to specify the Engine type for accurate information.

However, coolant leak means that it is coming out of somewhere and checking the thermostat will not help with the leak. What you need to do is to pressure test the cooling system and find the leak. As far as the thermostat goes, if the temp guage on the dashboard stays at normal (somewhere in the middle) then there is no problem with it and no need to do anything to it.

Possible causes of the leak can be as simple as the coolant cap being fauilty or loose or may be there is a loose clamp on one of the coolant hoses. So, test it before doing anything. By the way to test the cooling system will require a special tool to be attched on the coolant tank filler area. The best thing is to find a shop that only works on Saab and have them check and correct the problem.

I have seen Saab like yours suffering from coolant loss and run cool and all the sudden the coolant leaked at once and the engine was damaged. You do not want any coolant leak on this type of car it will cost you lots of money if the engine is damaged due to lack of coolant.

Again the cheapest thing to do will be to test for leak immediately and then correct the leak. Make sure you use Saab parts. The after market part is quite cheap and can fail in no time. Also make sure to use Original Saab coolant. No preston or Pepboys, autozone stuff. If you use those type you may damage the head gasket and again will cost you lots of $$$$.

[kiwibob7x]

Ok, first off, if you have the v6, you will have a heck of a time replacing the t-stat; I've heard it's a pretty intense job. If that's what's leaking, take it to a shop. The 2.3 is much much easier to replace the t-stat... take off the plastic cover in the back, and look under there on the driver side where the coolant hose goes into the engine block! piece of cake, maybe 30 minutes. Make sure you have the correct replacement coolant!

Seeing as I also own a 9-5, I'll throw in some advice for free: if you can track down the leak at all, the location can really help to tell you what it is... front passenger side is usually the water pump, a tough job, whereas the opposite corner of the engine (near the driver) would likely be the coolant (aka heater) bypass valve --- common problem. I've replaced all of these on my 9-5, so if you need any more help, I'd be glad to offer whatever advice I can!