Or at least that is what the gauge says. I just got the truck and am still working out some of the kinks. The person I got it from told me it ran hot, just under the red line.
I took the truck out last night for a twenty mile drive and the gauge went up above the red. Dropped it down a gear and raised the rpm's to bring the temp back down. I was able to keep the gauge just below, in and above the red zone. Not good.
It has a new water pump on it. So thought I would look at the thermostat. Pulled the houseing and found there was no thermosat installed. Put one in.
Refilled with coolant and started the truck. No leaks all is looking good. Well, waiting for the T-stat to open and circulate the fluid looked and seen there was also a new sending unit mounted next to the T-Stat housing (coolant temp sensor?).
Anyhow, now the gauge reads above the red area of the gauge. However, there isn't any way this engine is that hot. I can still hold onto the top radiator hose without getting burned. Without measuring the actual temp of the block, I just don't think it is that hot. If it was, wouldn't it boil over, oil on engine begin to smoke, engine smell extremely hot????
Is there anyway of measureing the sending unit? I am thinking either the gauge is wrong or the sending unit is bad. Short of going out and buying an after market gauge and sending unit, is there a method to troubleshoot this one?

 

Think for the money I'd replace that sending unit. Anything else is gonna be tough or more expensive. Manual gauges would be nice but gotta spend the bucks. If ya knew someone with one of those heat guns that will read surface temperatures that would rock. Maybe call around and ask some garages but doubt they would do it without the promise of some 'work' to make it worth their while.

Good luck with it and let us know how it turns out.

P.S. if it was reading right and was at the red mark you would be boiling over.

 

It sounds like you have a bad sending unit most likely. Your gauge is the next likely problem. I would replace the sending unit first and see if that helps because it is relatively inexpensive and easy to replace.

 

Thanks for the replies. I am hoping I am right and the engine isn't really getting that hot......betting the heads on it!!

I will get back with you when I figure it all out. Went to AutoZone, but they didn't have a sensor in stock. Computer said one, but shelf said none... Shelf won.

Will have to check at NAPA tomorrow. Small town, those are the only two auto parts places we have within twenty miles!!

Just wish there was a way of measuring this sensor to see if it was reading right, than I would be able to determine if it was the sensor or the gauge or me.

 

I believe you can check that guage out by disconnecting the lead, and grounding it. It should go to full temp while its grounded. Anyone jump in here if thats not correct.

 

Radio shack has a decent non contact infared temp guage for 29 bucks

just a thought I use mine for lots of other readings too

 

Well, it is a problem with either the sender or gauge. I did take the truck to a shop where one of the mechcanics "shoot" the engine, with one of the infared temp guns marthabefd was talking about. All the temps were reading well within the normal range. The gauge was trying to push the top of the cab off at the time.

The technician there said that some of the after market sender units are not calibrated to the specs needed by the Ford gauge, so they don't read right. Suggested going to Ford to get the proper sender unit. I may have to do that, but at least I know I was right and the truck isn't going to blow up on me because of overheating.

Thanks for all the advice and I may have to invest in one of those guns too, it was just neat at what all it measured. Temp of radiator, in front of T-stat, in back of T-stat, engine block, exhaust manifold, etc.... you could really get a good idea of where/if you had a heating problem. It was pretty cool!

I will get back to you all when I have some time to look at it again.

Thanks.