More cooling issues

[BIG]

94 YJ 4 Cyll -

Replaced the temp sensor and got the gauge working again - and now see that he gauge runs up to 210 - then to about 235 and then back to 210 and then back to 235.... not jumping around, just a slow climb and then falls back to normal at 210 and then it goes again and again and again? Tossed in a new thermostat, and it did not fix the problem!!! Where next? Fan Clutch, head gasket - I am at a loss. Any thoughts on what it might be would be and how to check would be appreciated.
I only mention the fan clutch as it was easy to spin when it was cold when I replaced the thermostat... I thought that when cold it should be harder to spin...


Thanks

Jeff

 

[massxj]

try a temp sensor

 

[beaker]

When was the last radiator flush?
It sounds like it's running a little hot but not that bad.  Usually if you can see the thermostat cycling, your still safe.

The cycling your seeing is most likely the thermostat opening and closing.  Try a good radiator flush and new coolant. 

The factory gauges are not known for being accurate.  Your gauge might be off.  That's why a lot of cars don't have numbers.

Wait for the engine to get over 210 again and dribble a little water (just drops, to much could damage the radiator) onto the top of the radiator (inlet side) / hoses.  If it's really over 212 the water will boil off.  If not the water will just evaporate off from the heat.

That or try a different gauge (aftermarket, while little better than a factory gauge, it's still a decent check).

Fan's are easier to spin when cold, not hot.  When the engine is hot, shut it off and immediatly try to spin it.  It should not spin easily / freely.

 

[Used-TJ]

Watching the evaporation rate of water dribbled on the radiator wont tell you much.
Youll see evaporation as fast at 190 as 212 - unless you have a calibrated eye

 

[BIG]

Thanks for the input -

There is no overheating in terms of visible steam - just the constant wide range of readings (up and down from 200 to 240 over and over. I did check the fan this AM when the engine was cold and it would move if pushed - but did not spin freely.... assume if when I get to work and check the engine when it is warm - if it spins freely I could have a fan clutch issue???

Thanks again

 

[ghiradelli777]

you could always add an electric fan from a taurus......it is an easy upgrade and then it will not over heat as frequently....

just another excuse to work on your jeep

 

[BIG]

and with the engine warm there was not much difference in the amount of "drag" on the fan / fan clutch from when it was cold.... is good or bad?

 

[beaker]

Not all fans respond to temp.  If it stops moving when you stop pushing, it's probably fine.  When they are bad, you can get them to do a full revolution or more after letting go.

What I meant above with the water was, if it reads 230 and water won't boil off, then it's really below 212.  If it reads 210, it won't make a diffence.