I've been noticing some steam rising from the grille of my 1992 900 S (NA). This happens exactly once per drive, lasts roughly 30 seconds, and coincides with the engine approaching operating temperature (and thus presumably the thermostat opening). It is most pronounced when it is raining (probably due to rainwater on the radiator evaporating), but occurs in dry conditions also, leading me to suspect coolant involvement. Any loss of coolant, however, is too subtle to notice at the expansion tank.
I have a pressure tester, but I doubt it would be helpful due to the brief window during which the steam is released.
in article slrncrbhn4.3d4.rotten_NOSPAM snipped-for-privacy@oragam.example.com, John B at rotten_NOSPAM snipped-for-privacy@ccil.org wrote on 07/12/2004 15:06:
Hi there!
You've answered your own question here. It's normal ... All classic 900s do this. Don't worry about it. It's quite unnerving when you first see it, not to mention embarrassing. Since you only notice it if you're stationary and, as you say, only for a few second I usually pull up quite close behind the car infront and pretend it's their exhaust :)
Nah! It's normal. Wait another 50,000 miles or so and replace the radiator. It's a hunded odd quid part and actually kind of fun to replace on a nice winter weekend.
Nothing to worry about ... Like the clunk when engaging reverse :)
Ah, very interesting. I've been driving this particular car for 10 years, and I've never noticed it before the last couple months. But if you say it's normal, that's good enough for me. Perhaps it is only normal for post-120k mile
900s?
I must confess to being tempted to do this also :)
Sounds good to me. Out of curiosity though, what causes this steam? Does a bit of coolant leak from the thermostat as it opens? I've been unable to pinpoint the exact source, since I'm always driving when it happens.
It sounds like there's just enough pressure built up right before the thermostat opens to send some steam out through a slightly leaky gasket or hose connection. Rubber does get brittle with age. I'd probably dump in some Barrs Stop Leak if you aren't already running it and see if that stops it. snipped-for-privacy@madmousergraphics.com
That clunk when engaging reverse is something to worry about. The local Saab shop has a gear with rounded teeth on display - rounded from clunking into reverse. Put in third gear, then reverse - you have no no more clunk :-)
in article snipped-for-privacy@yahoo.com, ma_twain at ma snipped-for-privacy@yahoo.com wrote on 08/12/2004 02:33:
Good tip - I've heard it's because there is no synchro on the reverse. I've not had a problem since my gearbox rebuild, but I'll certainly remember the third gear tip.
in article slrncrcadj.3s3.rotten_NOSPAM snipped-for-privacy@oragam.example.com, John B at rotten_NOSPAM snipped-for-privacy@ccil.org wrote on 07/12/2004 22:07:
There's always a time when a part starts to break down. In this case, it's the hosing to the radiator. Most likely the top hose. If you were to look under to bonnet and squeeze the top hose when it's warm, I doubt any kind of leak would be present. It happens when the thermostat first opens. The good thing about SAABs is that when something fails, it usually goes gradually. Have a look at the condition of the radiator and replace when necessary, along with the hoses.
I've had three C900s now - the first two were over 150,000 miles and 125,000 miles when I bought them and both had this problem. My current 900 was about
90,000 miles when I bought is and this is the first winter I've noticed this behaviour (120,000 miles at the mo'). My radiator is in a bad state and there are tell-tale signs of coolant leak at the top hose, although I cannot get the top hose to leak by squeezing/pumping it.
My first C900 had a puncture in the top hose, which slushed water all over the turbo! When I opened the bonnet, a column of steer soared from the car and covered the road. What a stink burning anti-freeze is!
It's as the thermostat opens - your engine top hose will have a slight leak when the thermostat first opens and the system is under the most pressure. I have also heard that water evaporating off the oil cooler (on turbo models) when the oil thermostat opens gives the same effect, but I've only ever noticed either wisps on the LHS of the car on a dry day or a more general smoke from the radiator in snow or rain. I suppose it's logical to think that perhaps any moisture on the radiator is also evaporated off, giving a wider spread of steam in wetter weather.
If it clunks going into reverse I would think the clutch is binding. Of course if you start the car without holding in the clutch then go straight to reverse pretty much any manual gearbox will clunk, but holding the clutch in for a few seconds should prevent that.
Don't forget that a C900 manual you most likely start with the gear already in reverse (and the clutch pressed down!) since this is the parking position when the key can be removed from the car. Thus the clunk problem is mostly noticeable during parking manoevres and alike.
Hi, my gearbox is quite noisy / worn, and I can even HEAR the gears coming to a stop 2-3 seconds after pressing down the clutch. This only happens if I press the clutch COMPLETELY to the floor. Shifting into reverse is smooth then.
If I shift into reverse before they stop turning then "CLUNK"! (Capitals on purpose ...;)
I got a good look at it in mid-steam yesterday, since I was lucky enough to be parking after a short trip just as it started. Steam seemed to be coming from all over the radiator, particularly the top half of the radiator. Not especially from near either the top or bottom hose. Ah well, I really should flush the system sometime in the next few months, so maybe I'll take advantage of that opportunity to replace the radiator anyway.
In any event, I have a more pressing issue now: it sounds like I just rusted myself a hole somewhere in the exhaust plumbing. One practically requires ear protection to drive the car now. Not sure if the leak is at the exhaust manifold, or down towards the catalytic converter. Any pointers on how to pinpoint it? If it's something I can reach in the engine compartment I might try to fix it myself, otherwise I'll probably give it to a mechanic.
Well, if there's a pinhole leak, the flush may very well expose that leak into a more pronounced hole, so yeah.
An exhaust manifold crack (between #2 and #3, almost always) is more of a hiss than a roar. If you have a roar, I'd suspect the header pipe, probably where the support that goes off to the back of the transmission is welded to it. Ahem, just a guess.
Exhaust work would be a snap if not for rust. It's one of the few things I won't do on my cars, and I do nearly everything else. I especially dislike rust falling into my eyes while I'm working on stuff, safety glasses or no.
The exhaust leak turned out to be easy to find, as it was a giant crack in the intermediate pipe (between the catalytic converter and the mid muffler), just aft of the collar where it bolts to the catalytic converter. I undertook to replace it myself, which was successful though a pain in the ass: the bolts holding the old collar to the catalytic converter were rusted beyond hope and had to be sawed off; and the intermediate pipe was separated from the mid muffler only after extensive heating with a blowtorch and much swearing.
And regarding the steam at the radiator, I dumped some Prestone brand radiator leak stopper into the system-- only time will tell whether that helps anything.
I read the threads on the steam thing recently and didn't have time to reply.
For what its worth, on my C900 I came to the conclusion that it was condensation on the engine block, built up overnight. Because:-
1/ I only noticed this in cold weather, when dew was likely.
2/ There was sufficient steam to indicate a leak, but no leak could be found
3/ The water level simply refused to drop a millimetre in a year of motoring.
I don't like water or oil additives, if you really have a leak, you need to fix the leak not fill the system with crud! (does anyone else remember the Mike Harding sketch and the eggs in the radiator?!)
My take on a likely source of this mysterious steam: (and I do remember this as a regular "feature" on my 1990 900)
When the engine cools and the fluid in the closed cooling system contracts it draws coolant from the overflow tank which creates a small vacuum in the tank. If I'm not mistaken, there is a poppet valve in the pressure cap that allows this vacuum to be relieved by drawing in outside air.
When you next run the car and the heated coolant expands it can eventually exceed the pressure rating on the cap (12-15 psi?) and release some of the air from the reservoir. This could be the source of the steam.
If this is the source, it should be easy enough to see if one were to watch it through an entire warm up cycle. But then again, I suppose this would fall into the "watched pot" category. It probably would not happen just because you were expecting it to...
We certainly have a lot of potential explanations for the steam. :)
I find Al's explanation to be quite creative, and I would believe it if not for the fact that I've driven the car for the last 10 years, and yet hadn't noticed the steam until this fall. Although I will grant that I'm probably more paranoid about my car than I used to be, so perhaps I'm just being more observant. Does anyone care to comment on whether they remember 900s doing this when they were new?
Fred's idea is equally creative, but I have observed the steam coming from the radiator itself, not the expansion tank.
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