Hey everyone,

Lately my engine temperature gauge on my 1974 ford f100 360 V8 has been running pretty hot. Today I took it out on the highway and about 10 minutes later the dash temperature gauge needle was almost on the far right "H" (beyond the TEMP writing on the gauge). Once I pulled off the highway and took some backroads in backed off a bit but still over the "P" letter in "TEMP". It consistently lives on the right side the the "M" no matter what or how I drive. I got home and let it cool thinking maybe it's low on coolant. A couple hours later I went out and pulled the radiator cap off and it was full of coolant with so signs of any leaks. I then fired it up with the cap off and turned the cab heat on full blast thinking eventually the thermostat would open and I'd see the coolant level drop. After about 15 minutes the upper hose was hot to the touch, the bottom hose was cold, the hoses running through the cab (I believe the ones for the heater) were hot to the touch and the truck was kicking out hot air through the vents with the needle on the gauge between the "M" and "P" in "TEMP". I watched and the coolant level never dropped during that timeframe. Eventually I could see the heat coming off of the coolant in the radiator opening where the cap was removed so I figured it was hot enough and turned off the truck. I then felt the top of the radiator and it was hot to the touch and the bottom was still cold, along with the bottom hose.

Being somewhat new to this whole truck and still learning based on what I've read, I'm curious what you all think this might be? Blocked radiator, thermostat, water pump, faulty gauge, etc.?

Thanks so much for any help you might have.

 

check the lower hose is not collapsing once it gets hot. i put a lower hose in with a metal wire inside to keep mine from collapsing and choking the water off to the pump.

 

Pick up a thermostat and gasket and some high temp silicone and change it. When your done take the old one and throw it into a pan of water on the stove and see if it is still operational. Now you will know for certain if this was indeed your problem. Keep it if it is still operational as a spare. Then we'll have to look deeper into what the problem is but start there.

 

This is sounding like a plugged rad. Drain some coolant from th truck and check the condition of the tubes if they look like below time to get the rad cleaned.

Also if you are pulling the rad flush the system out while you are at it and refill with a good HOAT coolant such as Zerex G05 or Motorcraft Gold. The green stuff belongs in the same place as Castor motor oils, in the annals of history.

 

Thanks i-w. The lower hose seems to be in good shape and has a metal wire in it to keep it from collapsing. I can feel it when I sqeeze it so I'm thinking I'm good there.

 

Thanks redroad. I'll start there. I read a lot where people put in high temp thermostats.... like ~195 degree ones. Should I be looking for that vs. a 160 degree or 180 degree one? Want to make sure I get the right one. Thanks!

 

Thanks matthewq4b. Say, where exactly is that picture located on the rad? You say to drain some coolant from the truck. Curious exactly how much I'd have to drain to get the same view of my rad that you show in the pic you attached? Thanks.

 

Keep the factory temp 192° ish once you start running an engine cooler wear increases dramatically.

That rad has had the tank removed. But you will be able to see the tubes through your rad cap once some of the coolant is drained down. Just drain from the drain petcock on the bottom of the rad in to a clean container. You will have to drain a couple few litres but you can put it right back in the rad once you have had a look. You will need to drain down anyway to change the Thermostat.

 

Thanks so much matthewq4b. I'll find a thermostat in the 190 degree ish range then. Also thanks for the clarification on the picture. I'll be sure to take a close look when I drain some for the thermostat replacement. Will probably post some pics of what they look like after I'm done being unless it's obvious I may not know.

Thanks!

 

@Fetch31 A discussion on thermostats can be as volitile as one about Ford and Chevy I'm a Robert Shaw high flow 195 degree guy on my FE motor
Here's a firery discussion on T-stats https://www.ford-trucks.com/forums/1...ermostats.html
What say you?

 

I would definitely recommend buying a high quality thermostat. It will save trouble later.

 

Thanks so much for the link redroad. You're so right... quite the discussion on them at that link. I'm going to need to read it a few more times to totally wrap my mind around all parts of it. I went online thinking I could easily find a Robert Shaw high flow 195 degree one for my truck (1974 F100 5.9L 360) and I seem to be struggling quite a bit. The highest I can find is a 180 degree one. I'm able to find a 195 degree one for a 6.4L/390 but not mine. Curious if you have any suggestions?

Thanks!

 

The 360 and 390 are both FE motors so that T-stat for the 390 will fit your 360. The factory intake manifold is the same on both motors.
Notice the water neck mounting hole is the same in size and location. A good budget upgrade on the FE motors is the 4 barrel cast iron OEM intake manifold. They can be had for $100-$150 and sometimes cheaper. The edlebrock 4-barrel FE aluminum intake is like $350 delivered. Something to think about. I was getting 12mpg with a carter afb 625 cfm carb on a 390 OEM 4 barrel intake and I felt there was more there to get.

360 4 barrel intake


390 2 barrel intake

 

Thanks redroad! I'll be picking one up this evening so I can work on that soon. Hopefully that's the fix! Thanks for the pics too! Helps a ton. I went and looked at my truck and it is an edelbrock intake and I believe it's a 4 barrel because I've got an Edelbrock 1406 600 CFM 4 barrel carburetor on it. I'm still learning a lot about this truck and new to working on a carbureted engine. I'm really liking it so far and thanks to people like you it makes it so much easier to learn! I'm only getting about 7 mpg right now but that was with me tuning everything and setting timing and such and really putting my foot to the floor to see if I could dial in throttle response. I'm not sure how much better I can get if I'm just doing regular driving with it. Hopefully a bit better. From what I read that might not be too far out of the norm though.

Also, I was wondering if my timing could possibly be causing the engine to overheat? I've got the initial at 22 degrees btdc, total at 37 degrees btdc and it seems to run great. With my vacuum advanced hooked up though I was getting close to 60 degrees btdc which I was reading was a bit high so I wasn't sure if that could be causing this overheating issue.

 

Your welcome What transmission do you have? 2wd or 4wd? Is yours a points distributor or?