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The temp rating on the thermostat doesn't mean the T-stat will be fully open at that temp. It's the 'cracking' temperature of when the T-stat will begin to open. It will take 20 degrees more above the rating stamped on it for the T-stat to be fully open.
A 180 degree T-stat won't be fully open until it reaches 200 degrees. A 195 degree T-stat won't be fully open until it reaches 215 degrees.
If the radiator isn't boiling over, then the engine probably isn't too hot. At idle, you aren't going to have as much air flow through the fins of the radiator to cool it. Above 25 MPH, a fan is useless since the ram effect of air flowing through the radiator takes over at that point.
If you don't have a fan shroud (assuming you have a mechanical fan), installing one would help funnel more air through the radiator when sitting still or at speeds of under 25 MPH.
We have tried running the engine with different t-stats with the same results and we have even taken the T-stat out and the results are the same. We are not using a shroud and the original engine did not have a shroud and did not overheat. However, it is certainly an option to try.
- Make sure you're getting the correct temp. Use a heat gun or temp probe to confirm you have the correct temp.
- New rebuilds sometimes get warm during the first few hundreds miles. They shouldn't but sometimes do.
- Make sure you're coolant is circulating. Also, did you change pulley sizes? I think the water pump pulley should be the same size or smaller than the crank pulley and definitely not bigger.
- Verify timing. Roughly 20-25 initial timing should be good (for example: 8-10 degrees mechanical advance plus 10-15 degrees vacuum advance should be fine)
- Like Ultraranger said, I kinda like a fan shroud when sitting still which I think they started using after 1967. And verify your fan is about half inside the shroud and half outside the shroud.
We have tried numerous gauges and temp guns and temp probes and they all show the same temperature.
The coolant is circulating and the pulleys are the same size as on the previous engine but the match what you are describing.
The timing is set as you described.
When I bought the new engine I also bought a new cooling system (radiator, pump and electric fans). We have tried running it with the old system and the new system with the same results. Both pumps are circulating coolant.
The only item I have not tried is a shroud.
We have even put high speed fans in front of the grill and it has made no difference forcing air through.
I went through this with my truck, I did everything to it, but nothing.
I put in a NOS thermostat, NOS temp gauge, Had the radiator rodded out, Put a shroud on it and my temp would still go up to 230° at this point I would shut it down for fear of ruining my engine.
After a couple of years of trial and error, I finally went to the "Fan Man" to have electric fans installed. When we installed the fans and ran the truck, temp gauge was hitting 230° again I shut it off. The guys at the shop replaced the sender with a known good one.
Fans will come on at 195° however my gauge would read 230° I'm not worried anymore. The problem has to be old wiring. Everything works so I haven't messed with the wiring to the dash.
Do like others have suggested and you'll be good.
This sounds just like my situation as we have tried everything. I would like to say it is old wiring on the gauges but we have tried every way possible of measuring the temperature and they all show the same temps so the readings are fine, the engine is just running hot. This is very frustrating indeed.
Guys, think about what you are suggesting. You're theory is that the rod and main bearings are so tight that they run hot enough to transfer that heat to the oil and then the block and water jacket? Please explain yourselves more thoroughly. You can be serious.... seriously mistaken.
Guys, think about what you are suggesting. You're theory is that the rod and main bearings are so tight that they run hot enough to transfer that heat to the oil and then the block and water jacket? Please explain yourselves more thoroughly. You can be serious.... seriously mistaken.
I don't know exactly what HIOSilver means so I won't put words in his mouth but I have seen fresh rebuilds over heat until they got "broken in". It shouldn't happen but does. My guess is that something somewhere is too tight.
To the OP, if you pull all spark plugs how easy does it turn over by hand? I don't know that I'd spend a lot of money on upgrading the cooling system. Run it on the highway about 500 miles and keep an eye on the temp or take it completely apart.
Have you split open an oil filter to look for metal shavings?
Edit to include 351 Cleveland C4's comment: If the walls were super thin, that might cause some over heat issues.
In 35 years and many rebuilds I've never seen what you describe unless the cooling system wasn't filled properly and all the trapped air allowed to burp out. I'm still waiting for a viable explanation.
I think '65 above is on the problem. Rebuilds have a lot of friction because of ring drag until they seat. It is common to have a rebuild pick up 100-150 rpm after five hundred miles of running because of the drag decrease.
Bored engines overheat. With .60 over, you have a water boiler. I learned that
decades ago.
I don't know about tight bearings but when Hio speaks, one should listen.
I'd like to see pics of what the OP has got.
2X all the above but also is it the correct diameter 390 fan? A radiator meant for a 390? Like maybe JY parts are working against you.
I'd like to see pics of what the OP has got.
2X all the above but also is it the correct diameter 390 fan? A radiator meant for a 390? Like maybe JY parts are working against you.
Is there a fan and a radiator specific for a 390? AFAIK, the 360/390 would be the same, but...
There are several different radiators, TWO different radiator supports and fan shrouds.
One of the fans uses a fan clutch. OP says the truck does not have a fan shroud, but it did have one originally.
A guy I knew had his F250 Camper Special 360 bored out, then the truck when climbing hills ran hotter than a popcorn phart. It was determined that the shop had bored it too far.
So to keep the truck from boiling on hills, he installed a sprayer. That fixed it, but...
If you don't see the coolant moving inside of the radiator, the head gasket may have been installed wrong.
The gasket covers the water jacket holes only on the right side of the picture.
Windshield washer reservoir with internal pump mounted to the left or right sides in front of the radiator. Windshield washer jets spray water on front of radiator.
2C-11500-A .. Windshield Washer Switch (same as 1952 truck starter button!) to activate this setup can be located just about anywhere on the dash.
Additional applications: 1965 F100/350; 1966 F100/350 with single speed wipers. Switch located on dash above the ignition switch on these trucks.
If you don't see the coolant moving inside of the radiator, the head gasket may have been installed wrong.
The gasket covers the water jacket holes only on the right side of the picture.
I'll bet you Gary nailed it on this one.
OP,If he's right you ought to REP him for it.
You can be serious.... seriously mistaken.
