Cj5 over cooled

roszko2

77 cj5 350/350 seems to run very cold. So cold that the needle didn't move all summer, I thought the gauge was broken. It has a mechanical fan, no shroud, new thermostat. I recently blocked the radiator with a piece of cardboard and temp slowly raised to 180 and remained there.

I realize most people have the opposite problem with heat management, does anyone have suggestions?

Mike

YJSam

roszko2 Hi Mike. I would suggest first checking with a laser thermometer the temp at different locations on the engine to rule out the sending unit being faulty. Then maybe changing the thermostat to a 195 degree thermostat. If that does not help, then possibly a smaller diameter fan may be used. Or, maybe even changing to an electric fan.

You're correct however, usually the questions arise on how to better cool the engine.

roszko2

I had replaced a 195* thinking it was stuck open. The fan sounds like a Cessna taking off so maybe a clutch fan or electric. I will definitely check the temps around engine.

Thanks

YJSam

roszko2 For sure try a fan clutch/fan set up over a rigid straight fan . It would help for sure as the fan would only engage once it reaches temp.

Klugar

A "cooler" thermostat (180°F) opens early & stays open, allowing coolant to flow quickly through the system. A "warmer" (195°F) opens & closes later, slowing coolant flow.

Without knowing the current temperature of the thermostat, the size of the radiator, the operation conditions, and the ratio of coolant to water a better diagnosis is difficult.