is my 300SE overheating??
 

Just purchased a nice used 1991 300SE ....
the car seems to run perfect..except the temp guage is always peged at 120c + after running awhile.

I used a thermal gun on the engine to confirm temps when the guage is pegged at 120c...this is what im getting...

Operating abmient temp is 75F ish (socali)
at thermostat housing 225F
at top radiator hose 180F
at bottom radiator hose 165F
at expansion tank 120F

do you guys think i may have a faulty "water-temp-sender"?
Please help.....as i dont want to risk overheat my engine...

Lead
91 300SE

sounds like a new thermostat is required.yours is prob stuck half open.easy job,cheap part.

At temps like that , you should be seeing aux high fan activation...do you ????

yes aux fans are comming on....and I'm turning on my heater to help cool her down...

Well, then as other poster says. change the thermostat ..
If high fan is coming on, it is not the gauge that is wrong.

overheating
 

I hope the head gasket didn't let go have you lost water or could be low on coolant but you must look to see what caused the problem like they said thermostat or a leak or water pump check the radiator for cracks at the neck

No coolant loss or smoke from tail pipe so far...so I think my head gasket is prob still ok...thanks guys....ill change out my t-stats as recommended.

replaced my tstat...temp guage now reads about 80-90c...thanks again guys for the great advice!