SaabCentral Forums banner

1 - 10 of 10 Posts

·
Registered
Joined
·
36 Posts
Discussion Starter · #1 ·
My '99 93 just started overheating yesterday. I was going to change the thermostat and do a flush & fill, but I have no idea where the thermostat is. Anyone got a quick how-to, preferably with pics? Anything else I should check?
 

·
Registered
Joined
·
4,293 Posts
The thermostat housing is at the end of the top radiator hose. Here is a link to some instructions:

Thermostat Replacement

Our thermostat does not usually cause the car to overheat. When it fails, it usually fails "open", so the engine either does not warm up, or the engine temperature drops while driving on the hwy in cold weather, and rises while in traffic or idling. In other words, the typical symptom of a bad thermostat is the opposite, engine too cold while driving, not engine overheating.

You may have another problem, like a bad electric fan, fan relay, broken wire to the fan, something else wrong with the ICE module... etc. Slipping belt on the coolant pump pulley, seized pulley or something wrong with the pump is another possibility.

If you post when it overheats, how long it takes for the needle to go from rest to normal (9 o'clock), etc., someone may be able to tell you what is wrong.
 

·
Registered
Joined
·
36 Posts
Discussion Starter · #3 ·
Thanks for the input. I did some acidental testing this evening.

I drove to the grocery store, which is about 5 minutes away. In that time, it got to normal temperature. I sat idle in the parking lot for another 5 or 6 minutes, and the temp guage didn't move. I also noted the radiator fan was running. I left the grocery and decided to go from one interstate exit to the next, which is about 1 mile. On the way to the on ramp (maybe 2 miles from the grocery) the temp stated creeping up. 1/2 mile down the freeway, I had to pull over as the guage was in the red. I let the car sit for about 15 minutes, with the key in the accessory position so I could watch the temp guage. After 15 minutes, the temp was back at the 9:00 position, so I tried to start the car, and it wouldn't turn over. The battery was plainly drained. I got a buddy to meet me with some jumper cables, and it jumped just fine. I drove it to the next exit, and then back to my house. Temp stayed in the normal range. I cut the car off when I got home and immediately tried to start it again, and it fired right up. So, I guess I need to check the belt tomorrow. If it was slipping, it may not be running the water pump and the alternator sufficiently. The car otherwise drives and sounds normal.

I did notice the other day, the first time the weather was cold enough for me to need the heat, I drove to work (about 15 miles, all interstate driving) and the temp needle never got out of the blue, and I had no heat.

Plenty of heat now though.

So, should I check somthing besides the belt? A new thermostat is like $8.00, worth trying one too?

Thanks again for the input!
 

·
Registered
Joined
·
4,293 Posts
I would check the belt and idler/tensioner pulleys first, it is easy, and does not take long. Then make sure the waterpump pulley and alternator are spinning freely and not binding.

If the battery gets drained while driving, it usually means it is not being charged by the alternator, when that happens, the battery indicator on the instrument panel should light up, at least intermittently.

If the engine does not warm up in 15 minutes of driving, then the thermostat is probably bad, but that won't kill your engine. Overheating will, so you have to get that fixed first.
 

·
Registered
Joined
·
21,583 Posts
The thermostat is good for 3 to 5 years, maybe 50K miles. Similar applies to the battery life.

The alternator brushes last 100 - 150K miles, then they are too worn down to be reliable and effective..

The pulleys and the serpentine belt are good for roughly 50K, after that point they should be checked once a month,IMO..
"Fan belts" used to slip, now this is almost impossible with the serpentine belt with its pre-set tension adjuster....

HF now has an amplified stethoscope on their shelves.. I think this is better than using a screwdriver to listen to the pulley bearings - if really bad, these could cause belt slippage.
 

·
Registered
Joined
·
36 Posts
Discussion Starter · #6 ·
OK, so if I tool around the neighborhood doing 25-30, it seems to stay at normal temp. If I go out on the main roads, 45-50 it will overheat in 10-12 minutes. If i turn it on in the driveway and let it idle, it will not overheat.

Any advice on checking the tensioner pully and water pump pully? Which one is the water pump?

Oh, and I'm at 85k miles.
 

·
Registered
Joined
·
4,293 Posts
phurst said:
Any advice on checking the tensioner pully and water pump pully? Which one is the water pump?


1 - Upper Idler Pulley
2 - Tensioner Pulley
3 - Alternator
4 - Lower Idler Pulley
5 - Crankshaft pulley
6 - Power Steering Pump
7 - Coolant pump
8 - Compressor

I would remove the air filter box first, then check the belt for tightness where you can reach it.

After that, release the belt tensioner carefully and lock it in place. Pull the belt away from the pulleys a bit and inspect the grooved side of the belt where you can see it. Then check the pulleys starting with the upper and lower idler, tensioner, p/s pump. coolant pump...

A dry idler pulley will spin freely, like a top, and make a slight noise (dry means the grease is gone). A good idler pulley will only turn maybe 1-2 revolutions (the grease stops it from spinning), and makes no sound. A pulley with a bad bearing or shaft will wobble in its axis as it turns, and may be visibly off vertical. A seized pump of alternator bearing will not turn freely. Etc...

If nothing is found, tension the belt again, run and rev the engine w. the air filter box off, listen and observe the pulleys using a good work light (safety glasses highly recommended!). The belt may not slip until higher rpm, if the problems occur at hwy speed.

Good luck.
 

·
Registered
Joined
·
36 Posts
Discussion Starter · #8 ·
First of all, the info and advice in this thread made great sense, and was very helpful and educational, but it did indeed turn out to be the thermostat (I think).


I drained the cooling system (coolant looked generaly OK, but I drained it into an oil collection pan, so I didn't look too closely).

Refilled with water, and ran the engine, with heat on, for 15 minutes.

Drained the water, refilled with water and cooling system cleaner, ran for 20 minutes. The drainage looked a little cruddy.

Drained and refilled with water, ran for 20 minutes again.

Drained, replaced thermostat, refilled with coolant, sprayed dead bugs off of radiator.

Been driving all day on and off the highway, and the temp is rock solid at 9:00 position :cheesy: .

Now to sort out the breaks, pass side ball joint, SID display, power antenna, etc.... :roll:
 
1 - 10 of 10 Posts
Top