I do not have an over heating problem in my 1949 F-1, just curious about the engine temp. I'm running a SBC, new water pump, 160 degree thermostat, new 3 core cross flow radiator with shroud, clutch fan. After I installed the a/c the temp increased by 10 degrees regardless at what speed. I figured it was the addition of the condenser. But at 100 degrees outside with the a/c on it will run 190-200 at 40-45 MPH. Bump the speed up to 60-65 and the temp will rise to 210-220. I'm using a 50/50 mix of coolant-water. I realize the frontal area is small. Any ideas? Should i run a straight fan? Go to a 180 thermostat?

 

Jack -

Changing the thermostst won't do much. I wouldn't worry about running up to 200. My engine likes it there. The 220 would worry me tho. My buddy has a 40 Ford Tudor with a BB and he has similar problems.

I would swap out the clutch fan for a straight fan and see how that worked. I would also try one with more blades or a bigger fan angle that is rated at a high cfm.

Are there areas in front of the radiator where the ram air can bypass the radiator? I would look for anything like that and block it (even temporarily) to see if that doesn't help. It's all about air flow over the rad. More the better.

Good luck. Keep us posted.

 

Sounds like you have one of those setups that's a bunch shorter than the Ford original and that it allows incoming air to go over the top of the radiator.

If this is the case, block off the opening from the fender/grille top to the top of the radiator core.

Mike

 

Thanks for the input, but I do have a pannel that covers that area.

 

Thanks for your input. In considering a straight fan also. The radiator goes from inner fender to inner fender. I might be able to stuff foam pipe insulation between the radiator tanks and inner fenders. That gap or space is 1/2" of less.

 

I think you might be wise to check your temp readings. There is a good chance that when doing the work, installing the a/c, the temp sensor may have been hit by something. This could cause the resistance value to change. Get yourself a lab quality thermometer and measure the actual coolant temperature. (Warm up the engine at idle with the radiator cap off, make notes of the temperature as it rises, both on your dash gauge and the thermometer and then you will really know where you stand.) I found through extensive testing that Stewart Warner temp sensors vary in value as much as twenty percent.

A couple of points: There is never any point in using a 160 thermostat. The engine needs to be at 190 degrees or more to insure complete fuel vaporization before it enters the combustions chambers. If it is cooler, you waste fuel which dilutes the oil film on your cylinder walls and may end up in your oil.

The other is, 220 degrees is perfectly ok. If it rises higher not under any great load then there is cause for concern. Read the lable on the container of the coolant you are using and it will probably give you the boiling point for the percentage of coolant you are using. Also remember the the boiling point increases substantially when the system is under pressure. If it's not blowing coolant your are most likely ok.

A question that comes to mind, would you get more direct airflow over your crossflow radiator if it were mounted vertically?

 

Bdox, thanks for the info. We put an IR therometer on the upper and lower hoses. The upper hose was right on with the VDO gauge. I'm going to pitch the 160 stat thats for sure. I do think the problem at speed 60 MPH + is the fan clutch and small frontal area. In and around town 35-45 MPH w/ac and never went over 190 degrees. So I'll go with a 5 or 6 blade fan. Appreciate all the inputs.

 

TBucketJack,
Unless you know for sure that the fan clutch is bad, I doubt that is your problem. As speed increases the fan becomes less and less a factor. If the problem didn't exist prior to the A/C installation, it also seems unlikely that the frontal area would be it either.

Try to determine if the heat build-up is actually speed related or if it is RPM related. Just drive it in second gear at the same RPM you reach in high gear at 65mph.

If it is RPM, then your lower radiator hose may be collapsing at higher RPM restricting the coolant flow. If so, install a stiffer hose. Even though the system is pressurized, the pressure is not equal throughout the system. There is a strong negative pressure at the water pump intake.

Another thought; re-reading your original post, I noticed that you said the radiator is new. Was it in before the A/C intstallation? Or did you intstall it at the same time? Did you have the same heat with your prior radiator or was it cooler?

I hate to see a guy spend a lot of money before you know the diagnosis is correct.

 

Bdox, appreciate all the input. The radiator was installed prior to the installation of the A/C. I will try the RPM in second gear and check that lower radiator hose. Thanks

 

I wouldnt worry too much about temps in teh 200 to 220 range. Engiens are designed to run at these temps.
On your 49 there should be a sheetmetal panel below and in front of the radiator that goes fromthe botom of the radiator support to the grill opening to help direct airflow through the radiator instead of below it. That panel gets left off of these trucks quite a bit because its different between the 6cyl and 8cyl trucks. There should also be a diverter panel attached to the hood that, when closed, helps direct airflow though the radiator instead of over the top of it.

A fan clutch is a good thing, if its not working usually tell because you can hear the fan at rpm (ie, the clutch is locked up) at rpm a fan clutch is supposed to let the fan freewheel. At rpm the airflow is enough to coolth engine without a fan, the fan is for intown stop and go driving.
A flex fan does the same thing by allowing the blades of the fan to flatten out at rpm thereby reducing the drag of the fan and the air it moves

good luck with it
Bobby