Hi everyone,

I have just changed my thermostat with new one because the car was overcooling on highway,

After changing the thermostat, I waited until the fans kick on to level the coolant but, the fans doesn't came on now at all , also , the coolant temp indicator doesn't go to HOT stays near N ... before changing the thermostat , my fans turns on in traffic but after iddling 15 minutes , the coolant temp gauges doesn't go UP , the fans does not turn ON , is that normal ? I can not drive my car until my repair shop , afraid of overheating the car , is the COOLANT TEMP indicator will show the over heat, I am sop confused about that , any way to check the fans ? My car is a Daimler 1996 six ( 4.0 ) lwb... thank you for your help !

 

First thing to check is the two 30A fuses in the junction box at the left front wing...sorry, I forget their numbers, but they are green and adjacent to one-another.

Then look at your high-side a/c lines on the right hand side of the bulkhead/firewall. Do you have the modification that brings your fans on when key is in position I? There will be two switch ports - if they both have wires going to them, then no, you probably don't have the mod. If not, your fans are actuated to "Low" by a/c head pressure or radiator tank temp, whichever hits it's trigger first (but it is common for the low-press a/c cut-in switch to fail "open" hence the mod) The fans are switched to "high" speed by the other a/c pressure switch at a higher pressure, or an even higher radiator tank temp. If they are switched to "high" before coming on at "low" then your two 30A fuses will be blown, or else will be failing in the near future.

Naturally, since this seems coincident to your thermostat change, I've assumed you've revisited all the electrical connectors involved to make sure they are properly secured? Radiator temp switch is on the left side of the radiator tank...follow the fan harnesses to make sure both fans are still plugged in, etc. etc.

 

Thank you @aholbro1

I think there is no modification to turn on the fans in key pos I ... I only changed the thermoststat , I did not touch any wiring , I main concern is : if the coolant temp gauges can show overheating , no problem, I can drive until my repair shop , in case of overheating , stop the car and wait... is that possible that new thermostat is stuck in closed position ? in this case the car will overheat ( no water circulation ) ,. can I see the overheat in coolant temp gauges ?

 

Sounds silly, but did you fit the thermostat the right way?

 

Thanks!!! everything is okey , I am coming just from short trip where there was traffic and fans go on without problem and with new thermostat , over cooling is also away so it does its job !!! thank again for helping me