Date: Fri, 14 Jul 2000 16:42:24 GMT From: saabsternopsameja.com Subject: Re: Themostat Swap
Went ahead with the thermostat swap, using a 180 degree thermo rather than a stock 192 degree one. Everything is a-ok. Been driving on the highway and the temp gauge stays consistently just below halfway, although during idling and stop-and-go city driving it can get up to 3/4 before going down to normal. No evidence of a cylinder head crack or a head gasket rupture--thank God!--but after I swapped the thermo I drove it around for a day and by the end of the day my gauge was, for lack of a better term, tweaking--i.e., jumping up and down rapidly. I opened up the old Haynes book and found it to be a severance of the wire leading to the temp. gauge transmitter; a little electrical tape provided a temporary fix. Thanks for the advice, though. This is my first car and three weeks ago I knew zero about auto mechanics, so I must say I'm proud of my little D.I.Y. repair jobs. Saabster 85 900 In article <396E1A9E.2DD5E6EDnopsamnetNOSPAM.se>, robert.brownnopsamnetNOSPAM.se wrote: > Hi, > > Changing a suspect (sticking?) coolant thermostat is where I'd start, too. > But if you have trouble finding the radiator drain plug you can detach one > of the radiator hoses instead. Or you can simply remove the bolts for the > water thermostat housing and lose a minimal amount of coolant that way (just > be sure that the coolant's not too hot and the expansion tank cap's loosened > to relieve pressure, otherwise you get it all in your face, as I found out > once ;-) No big deal with the coolant in the engine bay, just hose it down > afterwards so you don't get paint damage. > > As far as the bolts on the thermostat housing are concerned, just do them up > tightly and evenly enough so that nothing leaks (ya don't have to do them up > monster-tight). The rubber seal around the thermostat is supposed to take > care of possible leakages. > > You can safely remove the thermostat (or rather tear out the active bits in > the middle and retain the outer metal that holds the rubber gasket in shape > in the housing). The disadvantage is of course running the engine too cold > wintertime (bad fuel economy but that's about all). > > There are also thermostats that activate (i.e. open) at a lower temperature > but I have no experience of these so I'll let the other NG contributors > address that one. > > Another trick you can use to lower the temperature a fraction is to put the > cabin heat on full and run the cabin fan. This will dissipate engine heat > through the cabin heater matrix but you'll want to open your windows after > that one. > > Something strange about you having such a high "driving-around" temperature, > yet seeing the temp gauge go down when you're at the lights. That's the kind > of behaviour I got when my head cracked (that sure as hell cost me a few > hours' work) a few years ago. Without speculating further about the above > temperature change, here's a list of some things to check for when you're > getting overheating in general: > > 1. Sticking coolant thermostat, preventing coolant from reaching the > radiator in sufficient volume (you're already addressing this one). In > Sweden these cost about USD 10.00. > > 2. Electric fan thermostat (screwed into the radiator, find two wires) or > electric fan may be broken. Does your electric fan come on every once in a > while when the motor's hot? Test by shorting across the thermostat terminals > to see if at least the electic fan comes on. > > 3. Rotting cooling fins in the radiator itself (corroded metal does not > dissipate heat well) > > 4. Garbage in the radiator (leaves, etc) > > 5. Partial blockage of coolant channels in radiator or engine block (if so, > you'll have to flush and reverse flush radiator and engine block) > > 6. Rupture of head gasket or crack in cylinder head. Symptoms of this > include frothy oil on dipstick, coolant coming out the exhaust pipe (don't > confuse this with the normally small amounts of water that leave the pipe > due to normal combustion), engine missing on one or more cylinders when > starting cold, bubbling coolant due to exhaust gases entering cooling system > (can cause the expansion tank to rupture). These cases will also cause the > coolant to have a higher than normal temperature. > > 7. What have I forgotten? > > But check the first 5 points before seeking professional help on point 6. > Any garage would love to tell you you need a new cylinder head and get you > to pay for that . . . > > Under normal driving conditions and a wide temperature range (-5C to +25C) I > find that my temp gauge in my 1983 900 GL (8v no turbo single carb) stays > consistently at the half-way mark. I have a new coolant thermostat, newish > radiator, flushed everything etc. Not sure what a few degrees extra would do > but I doubt that I'd be up to 3/4 on the temp gauge, as you are. > > I hope your problem is easy and cheap to fix. Tell us all how things turn > out. > > Robert > Gothenburg > 1983 900 GL > 1999 9-3 200 > 1983 99 GL (r.i.p.) > > saabsternopsameja.com wrote: > > > When I came into Denver from Salt Lake City, I found the mountains just > > of Denver to be pretty hairy. Just to maintain 60km/h (about 35mph) I > > was in second gear and 4000rpm. The temp gague never did get past 3/4, > > so I assumed everything was ok. > > > > I parked the car downtown and explored Larimer Square and the historic > > district for about half an hour, and when I came back there was a > > massive pool of coolant on the street next to my ride. Naturally I was > > freaked, but was somewhat relieved to discover that the rad had no > > holes, the hoses were kosher, and that the fluid had leaked from under > > the expansion tank cap, which had a busted gasket. The next morning I > > went to the Mike Shaw Saab dealer on Colorado Blvd. to get a new cap, > > put it on, and in the days following the car was running a bit hot still > > but no longer leaking. (The temp gauge would get as high as 3/4.) > > > > Now the weather in Denver has this week been hot, like 90-95degrees > > (32-35celsius). I thought that might be the problem, but I went and > > bought a new themostat anyway. But it seems putting the thing on is > > going to be tougher than I had thought. For one, I can't figure out how > > to drain the radiator, since the crappy Haynes manual only says the > > drain plug is "on the right-hand side" and gives no photo or drawing. > > I've been told, though, that I can just take off the thermostat housing > > without first draining the system, but I don't want coolant spilling all > > over my engine compartment. Another thing (though this isn't a huge > > deal) is the fact that I don't have a torque wrench, and the bolts on > > the themostat housing are supposed to be tightened to a certain torque. > > Does it really matter all that much if it's not exact? > > > > I'm not sure I even need to change my thermostat at all. Driving around > > the city the gauge gets up to 3/4; then when I pull up to a stop light > > it'll go down to below halfway. That, to me, would indicate that my > > current thermostat is working peachy. > > > > Then I had some advice from this one fellow who recommened my removing > > the thermostat altogheter during summer--especially since I'm going into > > the heat belt of America after Denver (New Mexico, Texas, Louisiana). > > > > I'd like some advice here, fellow Saabsters. I'd hate to be stuck out in > > some Texas backwater with an overheated engine. > > > > Saabster 85 900 8v > > > > Sent via Deja.com http://www.deja.com/ > > Before you buy. > > Sent via Deja.com http://www.deja.com/ Before you buy.
 |
 |
 |
 |
 |
