1985-1998 [Subscribe to Daily Digest] |
[Main 9000 Bulletin Board | BBFAQ |
Prev by Date | Next by Date | Post Followup ]
Member Login / Signup - Members see fewer ads. - Latest Member Gallery Photos
Yes, and here's why Posted by Ari [Email] (#2847) [Profile/Gallery] (more from Ari) on Mon, 20 Jan 2003 08:29:42 In Reply to: Anyone ever notice rapid thermostat cycling below zero?, DickT [Profile/Gallery] , Sat, 18 Jan 2003 20:13:26 Members do not see ads below this line. - Help Keep This Site Online - Signup |
First off, the thermostat isn't cycling that much more than on a (relatively) warmer day. Thermostats always open and close regularly - that's how they control the temperature.
The thermostat is mounted in by the block. When the coolant temp hits the thermostat temperature, it open, and ports coolant from the radiator into the engine. When the coolant temperature at the block drops enough, the thermostat closes.
Let's pick a 40F degree (about 4C) day. The engine is running, but not hot yet. The radiator is at 40F. Finally, it hits 180F (82C), the thermostat opens, and a slug of 40 F coolant comes in. This mixes with the 180F coolant, the temperature drops some, and the thermostat closes. The temp gauge drops some.
OK, say it's 0F. Same scenario. But when the thermostat opens, it gets 0F coolant from the radiator. The thermostat doesn't open and close quickly, so you get a slug of about the same amount of coolant, but it's 40 degrees colder. The coolant temp at the engine is now, on average, quite a bit colder. The temp gauge drops more.
In really cold weather, the radiator works very well, so the coolant is that much colder out there. It's like dropping a bucket of water into your bath. It's makes a big difference if that bucket is warm or ice-water.
So it's perfectly normal. As to 82C, I run that with no problems. It will reduce the amount of heat from the heater somewhat, so it could be an issue at VERY cold (well below 0 ) temps. BUt I always get enough heat even on 0 degree mornings. The engine heats up just as fast with an 82 as an 89C thermostat. The only difference is 180F or 192F operation. As you've noticed, the engine is designed to operate over a range of temperatures - it still works fine at 180F, and idling at a light it can easily go over 200F. So I really don't buy the '180 is too cold' argument. And it does make the engine much happier in the summer.
posted by 192.249....
No Site Registration is Required to Post - Site Membership is optional (Member Features List), but helps to keep the site online
for all Saabers. If the site helps you, please consider helping the site by becoming a member.