Cooling System Help Needed!

[RWElphinstone]

Hi Everyone!

It's been a long time since my poor 1989 Saab has been on the road, ever since last fall, when she died due to a cooling system failure... I've recently been working to fix everything up, and have run into a snag in the final hours of completing the repair.

I need your help, as I've undoubtedly missed something along the way.

First, here's what happened. The heat in my Saab continually went through the roof, until such time as the coolant reservoir overflowed and sprayed hot coolant all over the engine bay. That was in the fall, when I decided to wait until better weather, and until I could afford the parts needed to fix her.

I've read through my Bentley, and figured that it would likely be better to replace everything important - so I ordered a new radiator, thermostat, thermoswitch, and top and bottom hoses. I've replaced the rad, thermostat, the thermoswitch and the top hose (I chose not to do the bottom, as it was near impossible to get to, with the - unworking - A/C in the way...) and drained and refilled the system.

To make sure the fans were working, I shorted the thermoswitch, and both fans engaged, so that was fine.

Now, I just went through testing the system, and unforunatley, something isn't working. The heat goes way up, and the coolant starts boiling in the reservoir, yet the radiator itself stays cool.

I'm having trouble figuring out what I might have missed, or what I have yet to figure out. Can anybody offer a suggestion? I'm thinking there must be something jammed up somewhere, and I can't figure out where to look next.

Help?

[900t]

Did you bleed the cooling system when refilling?

Possibility of the thermostat installed the wrong way?

Clogged radiator

[RWElphinstone]

Originally Posted by 900t

Did you bleed the cooling system when refilling?

Yes, and I believe it was done properly.

Originally Posted by 900t

Possibility of the thermostat installed the wrong way?

Can that even be done? I'll check that, though - it's a quick fix, if that's it!

Originally Posted by 900t

Clogged radiator

It's brand new, so I hope not!

[Matthew]

An air pocket behind the thermostat will cause the symptoms you describe.

On the thermostat is a bleed hole. The thermostat must be fitted so that the bleed hole is at the top otherwise you won't be able to properly bleed all air from the cooling system.

If that fails, for test purposes try running the car without the thermostat and see if the problems persist.

Got to ask this: any water in the oil or vice versa? A big overheat can pop the headgasket. A popped head gasket will cause overheats!

[philb]

Water pump working?

[RWElphinstone]

Originally Posted by Matthew

An air pocket behind the thermostat will cause the symptoms you describe.

On the thermostat is a bleed hole. The thermostat must be fitted so that the bleed hole is at the top otherwise you won't be able to properly bleed all air from the cooling system.

If that fails, for test purposes try running the car without the thermostat and see if the problems persist.

I'll check that! I wasn't aware of the bleed hole, and I'm certain that I didn't pay close enough attention to the re-installation - I'd actually removed it a week ago, and just got around to re-installing it now. (Funny story - I cracked my head open on my liftgate, when the shocks gave out during the uninstall, and my Wife didn't want me to continue with more that day. LOL.)

Originally Posted by Matthew

Got to ask this: any water in the oil or vice versa? A big overheat can pop the headgasket. A popped head gasket will cause overheats!

Everything's clean and clear, luckily. (That was the first thing I thought it might be.)

Originally Posted by philb

Water pump working?

Actually, that's one thing I didn't check - is there a simple test for this? (Or, if I run the engine without the thermostat installed, would this be a good test?)

[900t]

Ah your Saab tried to eat you! I've had that a few times...

[TooMany2cvs]

Originally Posted by RWElphinstone

To make sure the fans were working, I shorted the thermoswitch, and both fans engaged, so that was fine.

Now, I just went through testing the system, and unforunatley, something isn't working. The heat goes way up, and the coolant starts boiling in the reservoir, yet the radiator itself stays cool.

So you know that the wiring from switch to fans is good, but do you know the switch is working?

Clip a multimeter to it, and suspend it in a pan of water. Make sure it switches as the water gets to boiling.

[RWElphinstone]

Originally Posted by TooMany2cvs

So you know that the wiring from switch to fans is good, but do you know the switch is working?

Clip a multimeter to it, and suspend it in a pan of water. Make sure it switches as the water gets to boiling.

It's brand new, so it *should* work, however, the key indicator (to me, anyway) was that while the coolant was boiling over in the reservoir, the radiator was ice cold.

...yes, I was stupid enough to touch it directly. (I did, of course, check the rad hoses for heat first.)

[TooMany2cvs]

Originally Posted by RWElphinstone

however, the key indicator (to me, anyway) was that while the coolant was boiling over in the reservoir, the radiator was ice cold.

Aha... That's what's known as a "clue", that is.

You've bled the cooling system fully? When you did, water was being pumped round?

[Matthew]

And around in circles the thread goes...

[RWElphinstone]

I think I've got it - after a more 'thorough' visible inspection, it looks like I don't have the V-belt that should attach the water pump to ... well, everything else!

If the water pump is just under the AC compressor, and just above the engine pulleys (with a couple of pulleys on itself) then this might be the solution.

[TooMany2cvs]

Originally Posted by RWElphinstone

I think I've got it - after a more 'thorough' visible inspection, it looks like I don't have the V-belt that should attach the water pump to ... well, everything else!

<boggle>

If the water pump is just under the AC compressor, and just above the engine pulleys (with a couple of pulleys on itself) then this might be the solution.

Yup. The paired belts should go round that as well as the alternator.

[Matthew]

That'd do it.

I'd be tempted to get the engine tested for head gasket failure (hydrocarbon and compression test) even though the oil and water appear clean.

[RWElphinstone]

Originally Posted by TooMany2cvs

Yup. The paired belts should go round that as well as the alternator.

I have a pair on order, and will be picking them up tonight!

[RWElphinstone]

Well, lo and behold!

Installing two V-Belts around the Alternator and Water Pump worked BEAUTIFULLY!



It took me awhile (and a lot of scrapes) to adjust the tension on the various components required to remove the existing drive belt, but once I got all of the belts installed, the car warmed up, the radiator got warm, the thermoswitch engaged the fans, the radiator cooled and the fans shut off successfully.

I'm happy with the results!

[TooMany2cvs]

Originally Posted by RWElphinstone

Well, lo and behold!

Installing two V-Belts around the Alternator and Water Pump worked BEAUTIFULLY!

Would "What happened to the old ones...?" be a silly question?

[RWElphinstone]

Originally Posted by TooMany2cvs

Would "What happened to the old ones...?" be a silly question?

I don't think it's a silly question.

I bought the car from a friend of mine, who had it sitting in his driveway for about a year. He had bought it for his Son, who didn't want to drive it (!) because his parents had just bought a brand new SUV, and he'd rather drive that (!!) than the beautiful Saab 900S.

So, long story short, I bought the car and had it certified, and I can only assume that, while looking over the car, my Mechanic was probably caught unawares that there should be two V-Belts surrounding the Main Drive, Alternator and Water Pump, instead of one. I would think that it probably just 'gave out'...

I've since made certain that there are two belts on there now.

[TheRedBaron]

The two belts are there just in case one fails - it will still work. Sort of like pairs of jet engines and male organs.

What this means, is that your mechanic found a short belt to bypass the water pump and only run the alternator. How he did this...well...just find a new mechanic.

[IronJoe]

Holy cow. No belt around the water pump?!