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OM617 Operating Temp

Started by SuitGuy, 22 August 2021, 01:43 PM

SuitGuy

Hi all!
I noticed as I was driving at highway speeds the engine temp would climb to ~90-95 C after a short while and climb no higher. She'll cool down after five or so minutes going downhill. She also seems to do this whenever climbing any steepish hill in 4th gear. Is this outside of normal operating temp or is this within spec? Just a worrisome owner.
Kindly,
SuitGuy
Beige 1980 300SD

raueda1

What's the outside temp?  And remind us of the model?  Anyway, if it's hot out I wouldn't be worried.
-Dave
Now:  1976 6.9 Euro, 2015 GL550
Before that:  1966 230S, 1964 220SE coupe, 1977 Carrera 3.0

rumb

Seems fine to me.  As long as it cools down again when not working the engine hard , this is normal.
'68 250S
'77 6.9 Euro
'91 300SE,
'98 SL500
'14 CLS550,
'16 AMG GTS
'21 E450 Cabrio

SuitGuy

It is an 80 300SD, and it isn't inherently hot out, maybe ~75-85 F or ~23-30 C. The other day it ran at highway speeds at ~82 C, so I'm probably working myself up over nothing. The water pump was changed by the PO, so that does not concern me quite as much. The fan clutch seems rather ordinary, but finding a replacement clutch will be difficult to find. Would this cause a slight overheat at highway speeds?
Beige 1980 300SD

raueda1

I wouldn't consider 90-95 deg a slight overheat at highway speeds on a warm day. 
Does fan clutch spin free or is there some resistance?  If the latter then it's likely OK.
-Dave
Now:  1976 6.9 Euro, 2015 GL550
Before that:  1966 230S, 1964 220SE coupe, 1977 Carrera 3.0

UTn_boy

Quote from: SuitGuy on 22 August 2021, 07:24 PM
It is an 80 300SD, and it isn't inherently hot out, maybe ~75-85 F or ~23-30 C. The other day it ran at highway speeds at ~82 C, so I'm probably working myself up over nothing. The water pump was changed by the PO, so that does not concern me quite as much. The fan clutch seems rather ordinary, but finding a replacement clutch will be difficult to find. Would this cause a slight overheat at highway speeds?


The fan clutch is only for low RPM. For example, sitting in traffic or driving in traffic that is crawling.  At highway speeds the fan should pretty much free wheel.  If it's coupled at highway speeds then the fan clutch is bad. 
1966 250se coupe`,black/dark green leather
1970 600 midnight blue/parchment leather
1971 300sel 6.3,papyrus white/dark red leather
1975 450se, pine green metallic/green leather
1973 300sel 4.5,silver blue metallic/blue leather
1979 450sel 516 red/bamboo

Engineerd3d

I took my 1980 300sd out for a drive in 95f+ weather. She would not go over 82-85c. This is while going city + highway -75mph. Also ac was going on and keeping the cabin cold.