Date: Fri, 10 Jun 2005 10:50:48 -0400 From: Malt_Hound <Malt_Houndnospamm*yahoo.com> Subject: Re: Overheating=(
es wrote: > hi my 1990 9000 cd turbo is overheating the fan is working theres no > leaks but it overheats in traffic not on the highway. idles good runs > good but it really gets hot when the car is not moving. it was good in > the winter but now that its hot out it Overheats. > > > what could it be? > I have read all of the responses you have received thus far and nobody has given you the correct advice yet. The key to diagnosing your problem is something you stated above: "overheats in traffic not on the highway." Think carefully about that statement. What this is telling you is that, when the engine heat load is the highest (at highway speeds) the temperature is normal, but when sitting still and idling (lower heat load) the engine temperature climbs. Those symptoms indicate that the majority of your cooling system (radiator, water pump and thermostat) is relatively healthy. It will do its job if you get enough cold air flowing through the radiator. You also stated that the fan is running. 9000s have two speed fans which are thermostatically controlled. When the radiator temperature gets above a certain point (or if the AC is on) you should hear the fan's high speed kick in. Without the high speed the engine temperature will climb in summer's heat. The original set points on the thermostatic fan switches were too high (92C) IMO. Switches with lower set point (82C) can and should be bought. I would combine that switch upgrade with a lower temperature (82C vs 92C) thermostat. And no, you should never just remove the t-stat. They are not that hard to get to and change, and also a cooling system flush/fill with SAAB (blue stuff) coolant. http://townsendimports.com/Web/entry/tech_doc_systems.htm Go to this web site and read up on the cooling systems info in the technical documents. There is wealth of information here. Do not allow your SAAB engine to overheat again or you will very likely get to replace the head gasket. (much less fun) I've owned 2 9000's, (still have one) both of which exhibited cooling system problems such as yours and worse. In both cases, after upgrading the switch and thermostat to lower temp units and flushing / filling with blue stuff, they have run many trouble free miles. -Fred W
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