Temperature gauge goes between 140 and 230 degree and back and forth

nacamp

I have a 1994 Ford Explorer Limited 4 wheel drive V6, auto
transmission. The temperature gauge keeps going up and down from
140 to 230 degrees and back. The radiator was replaced because of
a leak, the radiator cap was replaced, the thermostat was
replaced 3 times, the anti freeze was replaced and flushed 3
times. A new mechanical gauge was put in same problem. The anti
freeze doesn't go down so no leaks. There is plenty of heat from
the heater. The truck doesn't boil over. Ford doesn't know, they
don't believe it a head gasket. Two mechanics looked at it and
can't figure it out. Help if you can. Thank you in advance.

lucky20

230 deg. I is not enough heat to boil antifreeze coolant mixture under pressure. If this heat difference is occurring as the gage indicates, it can be confirmed by infrared temp. tool or electronic pyrometer. No mention was made about the outside (ambient) air temp. or if the problem remains the same in cooler or warmer ambient tempretures. Question to be answered. Where does the water temp. differential occur, in eng. block, head, at thermostate housing, etc. or does it occur at all? Has any attention been given to the fan clutch? Even though the thermostate has been serviced more then once, it is highly suspect.

bblaha

Bad senser?

How quickly does it fluctuate? If you're talking seconds, then its a senser. The coolants actual temperature isn't going to change quickly

cjmny

take a look at post about problem i keep having with my volvo 240:

Volvo 240 - Overheating Problems
3 messages,Last post on Jan 18, 2001 at 10:58 AM

the general consensus is that its a sensor and not a real overheating situation. very frustrating !!!!!!

2k1trd

Sounds like a headgasket to me.Have someone block check it.