Temp Gauge question

Northwind

Northwind

Well-known member
Drivng a 1990 110 ex mod 2.5NA diesel that i picked up last year, What ive noticed is the gauge inches up some when running at 60-65 but doesnt go into the red. If i am driving around town in the 45-50mph range the needle sits square in the middle. This typical for a 2.5na or am i just being paranoid? Since i know little to nothing about stuff like this i figured id ask the experts. Any insight would be greatly appreciated. Thanks
 

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1of40

1of40

Well-known member
I’d advise that you consider an investment in a $20 hand held IR temp gauge. Use it to check the temp at the thermostat housing. This will help you know what the temp is and therefore what the engine is experiencing. If it’s on the high side then it sb figured out. Could be corroded rad, weak water pump, bad thermostat, etc. When I owned a NA the temp never got above 185.
 
Jeff B

Jeff B

Well-known member
- you can also use the IR temp gun to determine the temperature of the seat box of a V8 Defender when running in Virginia when its 91*F .....LOL


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Uncle Douglas

Uncle Douglas

Well-known member
Callsign: delete
Problem relates to the way a 2.5 is geared. @ the lower around town speeds your engine is turning fairly low rpm and coolant is moving through the radiator @ a rate where there is adequate heat exchange. The high rpm required to make a 110 do 65 with a 1.6 transfercase has the coolant moving through the radiator very fast due to engine rpm and not enough heat exchange is happening.
A healthy example can go 65, but was not designed to, and will require lots of maint if used that way.
 
Northwind

Northwind

Well-known member
Appreciate everyone's response on this. UDoug makes total sense, spoke to the garage i use and they pretty much said the same thing. My goal was to drive to the lake cottage this summer, 125Miles from home, will still do it but maybe more in the 55mph range via an alternate route than the freeway.
 
RDavisinVA

RDavisinVA

Technical Excellence Contributor
2.5 is dangerously slow on the interstate.
I pulled out driving one and a car 5 miles back had to swerve to avoid rear ending me.
 
RDavisinVA

RDavisinVA

Technical Excellence Contributor
Am not aware of any 2.5 diesels having anything other than a fixed fan bolted directly to the water pump.
Did some of them have a viscous unit?
 
Northwind

Northwind

Well-known member
So the issue got worse today on the interstate, only had to drive 15 miles to the local nursery and the temp gauge kept rising. Never hit the red zone but was all the way to the right (against the white). Temps here in Minnesota hit the 90's (shocking) so it was a hot day. Regardless i got home and texted the guy who imported the vehicle for me. He said it probably has an 80 or 88c thermostat and that i should go to a 76c, so of course i ordered one from Rovers North. Quite frankly i dont know shit about this stuff so have to rely on others for advice.
 
1of40

1of40

Well-known member
Maybe get an IR temp gauge. How fresh are ur fluids? If you have a bad head gasket or unpressurized system this will cause overheating too.
 
Uncle Douglas

Uncle Douglas

Well-known member
Callsign: delete
Thermostats are cheap and easy to change and is certainly the cheapest place to start.
Clays suggestion to pick up a cheap IR gun would allow you to see if the gauge is reading correctly
and also allow you to see if there is adequate temperature drop with the radiator.
Not sure I buy the suggestion to use a lower temp thermostat. That just opens it @ a lower temp, doesnt open it any wider
or allow more flow. Diesel engines actually need to be up over 180 degrees to run well.
 
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