71 280SE 3.5 Coupe - Water Temperature

[Dbglobal]

What water temperature should I be gettimg while driving on a highway, when the outside temp is between 60-70 degree's? I get a reading around 190-200 degrees, is this normal?

To reduce water temperature should coolents be added to the system?

Thanks,

Dave

[pchbreeze]

You're not in the red so you should be ok but if it has been high lately I would flush the system. if you also have the 3 speed auto that sounds right (that its a bit warm on highways at those temps).

Actually coolant will reduce heat transfer. If you're not worried about freezing temperatures, you can run pure water for best efficiency but you'll want to add a rust inhibitor also to give your engine life.

[Tomguy]

You may need to flush the coolant system. You might want to replace the thermostat, too. Ideally, it should be 175° at those ambient temps even in heavy traffic. It can indicate a weak system, meaning when it's hot out you will get into the red. These engines, unlike modern ones, like being 175° - my Jeep, 300m, and Charger like being right around 210°-ish at those temps.

[sjefke]

I agree with others. Seems a bit high. Temp in my coupe can definitely get up there in heavy traffic and fast uphill highway speeds, but goes down pretty fast when cruising 60 mph. Plus we are talking 80-90 degrees Georgia climate. Sounds like you need to check your thermostat and fluid levels. Also, do you have the AC running? Adds to engine load. Another thing to check would be the ignition timing. If it is retarded, engine may run a bit hotter, if I remember correctly (I may be wrong).

Bert

[ABDow]

Agreed it's too hot. Where I live can get up to 45 centigrade in summer and I have wired the air conditioner fan (the electric fan in front of the radiator) so that it always goes on when I turn on the A/c. This means that you don't have to wait for the thermo switch to kick in. If the timing was retarded it can make it hotter and it would also feel gutless at low revs.