Engine temp?

[ROBT257]

I probably just missed it during the search. But here is the issue.

The dash guages are old and I'm just not sure they are working correctly. The temp reads to the far right just to the left of the H. No numbers on the gauge. This is worrisome. I've looked around and think the normal optimum operating temp is 192 degrees. Well my uncallibrated since of feel on my skin from a few inches off the engine is just not up to the task. So I bought one of those Mr. Gasket thermometer radiator caps, to give it a try. Coolant temp is what I'm looking for rigth? Well I put it on yesterday. Low and behold my uncallibrated sense of feel seemed to be getting lower readings. Hmmm I said to myself.

I let it idle for for about 45 minutes. The cap read around 170. I drove the hell out of it for about 25 miles on the highway then about five on the dirt road alternating from full throttle to barely rolling. When I got home it was still reading only 180.

So is the cap just a waste of money?

Oh and by the way....I noticed it was marked 13psi. I think the original was 15. Will that make a difference? And is it OK to leave it on?

[thebannister8]

how old is your sending unit

[Dragon]

Sending unit wore out or voltage regulator behind dash putting out more that 5 volts.

[ROBT257]

I'm assuming its all original and just a little older than me!

Though I guess I hit a bump or something just right today. The fuel gauge and guel temp starting working again! Aint that some crap. Temp reads just left of middle. So I guess thats good! The Mr Gasket still read just shy of 180. So I guess I panicked for no reason and just had a short that not only affected my fuel gauge (which I knew of) but also the Temp too.

While I was typing this reply I called the fire chief of the VFD where I bought the truck. He said the sending unit was changed around 8 years ago when they replaced the heads. They had the radiator flushed at that time too. So I guess my problem was electrical behind the cluster and nothing to do with the engine.

[ROBT257]

Well now I'm reading at 220. Is this a probelm? Is this too high? Will it cause damage?

[george worley]

Is that 220 siting still or moving. That temperature seems a might high to me. My 390 with 3 core rad. and 180 stat will run about 200 in 90+ heat in traffic and cool down to 180 on the road. Maybe you should try a aftermarket gauge that has the temperature in degrees. My stock gauge seldom reads the same as my aftermarket one and they are off of the same tee fiting. There is a great thread that tells you how to use the stock and the aftermaketgauge together.

[FordTruck]

My 302 usually runs about 180. I've driven it in hot and cold and hardley ever gets above 180 or so.

[wildcard]

My 300 runs about 185 until you stop in the summer, then it gets up to around 205.

[cdherman]

Since your other guages are also moving around randomly, I'd first suspect that the voltage unit behind the dash cluster is gonzo.

If the other guages have been stable, then its likely the sender, UNLESS you overheated.

I once saw my sender die -- I was crusing down the interstate on a hot day and suddenly I saw the temp go DOWN. Dropped to about 160 -- had been right at 185. I KNEW the engine temp did not change that fast.

Interesing thing is that I replaced it with a new sender, and that one read 205 when hot. So I replaced that one, and the new one read 215 when hot.

So I think the one that died suddenly was not right at 185 either.

In any case, the real reason to have a temp guage is to watch it for changes. The numbers on the older guage are largely meaningless. So is the needle position.

What matters is where its at compared to where it usually is. If you are cruising along and it starts to inch up higher than it usually is, you have to worry.

Mine has been at 215 now for 4 years. Never boiled over yet. I figure its OK......

Temp guages should usually remain pretty stable in engines -- remember the thermostat varies the ammount of coolant flowing through the radiator. In fact, the radiator cap based thermometer can be quite misleading. The engine should ALMOST ALWAYS be running at a higher temp than your radiator. When the radiator and engine are the same temp, it means that the thermostat is maximally open and any additional heat from the engine cannot be dissipated efficiently.

Of course, the thermostat cap is on the top of the radiator, where the hottest water is. Coolant at the botton is MUCH cooler. Or it should be!!!

When a sender dies it usually shows LOW temp, at least in all the instances I have read about or experienced. I would worry that NEW high temps are either a) real b) dash cluster voltage regulator failure.

[19FORD67]

Is your fan shroud missing?

[ROBT257]

No the shroud is there and appears to have the proper spacing with the fan iside partially. My OEM gauge reads maxed out all the time. But that only started happening when the fuel gauge also quit working. So I'm thinking something electrical in the dash. I'm now starting to get worried because after sitting at idle for about 20 minutes on a 100+ day it spewed over. I do know that it had overheated on the original owner a few years ago and cracked a head. I surely don't want that to happen again.

I know I need to get the guages fixed but thinking I might need to change out the thermostat anyway. It may be time for a new radiator as well.

[FordTruck]

Put an aftermarket temp gauge on it that reads from the intake if you don't already have one. I don't trust my OE gauges to work so I have oil,temp,volt all seprate just to make shure.