Running temp

[Tomguy]

Today (for the first time in about 4-5 years) I took the MB out on a long(er) trip (about 30 mi round trip). I noticed that not at one point did my temp get higher than 175, and a lot of the time it was below 175. Which makes me ask: What should the running temp be? If the thermostat is 90C then I am about 15C below what I should be, right? (175F = 75C about)

[tosbt]

Your doing real good at 175F. Keep it there if you can, 180 or 185F is OK, but I wuld look for problems over that. 190 starts to bother me. is ok, but on the edge.

[Tomguy]

My Jeep ALWAYS runs at 200-210. That's why I ask. I know engines get higher efficiency the warmer they run. What does everyone else's run at?
I figure maybe my thermostat spring is weak...

My '72 280SE 4.5 runs at 175 to 180 including up hill in air temps at around 100+

[Tomguy]

wow, I thought I was running cold... I could have sworn it always ran at the line above 175 (190?)... but maybe that's why my cams and rocker arms got cooked?

[Darrell Woods]

75 450SL with 72 300SEL 4.5 engine runs consistently at 175-180.

[stejm]

Question about my 71 250 - I've had the car for a year, and had constant running temps around 175-180. Last summer was pretty mild, but the temps this summer have been higher. As a result, I was running about 190 in stop and go. A couple of times it ran over 200, nearing 212, but went down once I reached speed.

The past few weeks it's been running at 190 constantly, even at speed. On a whim, I grabbed a piece of hose and listened to my carbs. The front was much louder than the rear, so I adjusted the idle speed to get them close to sync. Now, the car runs a steady 175 (even lower at speed) but still heads to 185 when sitting.

After parking for a while, I've noticed the temp sitting at 200. When I start the car, it drops dramatically.

Is this normal? My coolant is currently 35/65 as I live in socal and won't ever need to worry about temps lower than 45 degrees.

[abe g]

I woouldnt worry about 200 degrees (on guage) unless you see other signs of overheating. My 1977 450sl was running at 200 f for about 4 years, then witout any coolant change or any changes, it started to run at 175 f to 180f ! You have to anticipate that guages can fluctuate and other signs of overheating (loss of coolant, slight steam , etc) are the things to look for. Check your coolant regularly and dont rely only on guage! Good luck, Abe G

The gauge on both of my parents' vehicles go up to about 220 if the car is parked and shut off, but when you turn on the vehicle is goes down to where it normally should be.
Tim