Water Temp Gauge Needle Moving Up/Down?

have the sensor checked first.

 

I would imagine the fluid is not adequate in volume, or full enough inside the area the temperature sensor sits. Once the fluid level drops too much there is nothing on the sensor and your needle drops fast. When more fluid sloshes through it again boom back up it goes. At some point if you don't have enough cooling it's going to overheat and keep going until engine shutdown.

It is a small thought that if your cooling gets hot, take a look at your engine oil pressure and see if it has dropped say 10 PSI from normal and then check to see if the engine oil temperature has also started rising. If you are running a liquid transmisson cooler check that temperature as well. If all agree and getting warm then yes your coolant is no longer cooling.

There is a chance that the sensor inside the engine is bad feeding information to you that is not correct. It should be easy enough to replace the actual probe itself but you will have to dig down to get to it. Ive had probes go bad before when they corroded then fed bad temp information. That is usually confirmed on a dyno session designed to force the engine to overheat and quit. Ive ridden three of them via the passenger seat and believe me if it's going to burn it up it will do it then and there on those monsters.

All the mechanic saw was that needle flapping back and forth and shes pulling on that Dyno trying to make it stop. So that gave them something to consider and that was how we found the problem that time with the Probe or sensor going bad.

Another time we had persistant overheating and found that the radiator cap itself has gotten too weak and refuses to pass the pressure test applied to it. It's supposed to hold about 15 PSI when the test tool is applied to it. And if you cannot hold it you cannot cool it. A new cap fixed it.

Im sorry that I cannot offer do this or do that. It is a risk with today's modern computer engines, lose a pint and boom computer wants to shut down everything. It's silly. If it was me, I'll take it to the bigger shop with the understanding that if you duplicate the overheating on the way there then that's ok. A tow is not ok, but you need to find the problem and fix it.

 

On the road with no tools water is a good temperature gauge. Stay away from the exhaust but pore some on top of the cylinder head. It boils at 212F. Stop if hot and go if not.

 

Just shoot at the thermostat area on the head and or anywhere else on the head away from the exhaust.

 

Another example of highway robbery

 

did that fix the issue?