MTFCA Forum

My 26 Roadster pickup has a 2 row round tube radiator and a replacement short fan hub with the modern bearing. The cylinder head temperature runs up around 250 degrees, according to my infrared thermometer. My question is, could the short pulley, positioning the fan further from the radiator, be causing the engine run at that higher temperature?

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Ford made a long hub fan pulley for their skinny radiator. But I don’t thing they were just 2tubes.
John is right, get a good radiator with more tubes. Best money you will spend on your T.

Hello Scott.... in the beginning of the improved version of late 1925 the five row radiator was being used and late in production of that year ...1926... a three row radiator was being produced eliminating the five row. Using water as a coolant in a thermosyphon system will start to circulate at about 190 - 200 degrees F. ... and will produce sounds of boiling after engine shutdown....and the engine temp. will increase. Using antifreeze coolants will vary temperature readings compared to water.

The fan is most important in cooling when idling and not moving such as waiting for a signal. If the engine overheats when moving along at normal cruising speed, you have radiator problems. Some people even remove the belt for cruising without a problem. But if you climb hills or are in start stop traffic, you need a good fan and belt. The length of the pulley is made for fitting the various thickness radiators. If the fan does not hit, when using a longer pulley, OK but with a thicker radiator a shorter one is best.
Concerning the radiator. Old radiators can be clean inside but still not cool properly because the connection between the cross fins and the tubes becomes corroded and the heat does not transfer. The flat tubes cool better, but for some "purists" they are not correct.
You will need to decide for yourself what combination works for you. Most people today, would never know the difference between the two. They don't even know what the cars are or the year model. I use the flat tube radiator and have never in my over 30 years of driving had anyone criticize them. They don't usually overheat unless the coolant level drops too low. I have learned a lesson to check the coolant from time to time, even on a tour because it is not a closed system and anything which boils out or goes out in steam is lost.
Norm

Sorry, the radiator is a 3 row, my mistake. I am pretty sure that the fan is on the right way, but I will look and confirm that. Is 250 degrees cylinder head temperature too high on a 90 degree day running 50/50 antifreeze? Will putting the longer fan pulley on it, bring that temperature down? Ford surely used it for a reason.

Just checking parts book, Ford had 4 core configurations for the tall radiator, single row flat tub, 3 round, 4 and 5.

Can you comfortably hold your hand on the LOWER radiator hose PIPE (return)? bobt

Scott, the pulley for the 3 row radiator on my 27 is one inch longer than the new pulley I bought after installing a 5 row radiator.

The overall pulley length is 3.2". Here it is being held up to the new one. I drove a lot of years with the 3 row and was accustomed to hearing the water/coolant circulating quite noisily after engine shut down. It must have been boiling because you could see steam coming out of the overflow tube for a couple of minutes or so until everything cooled down.

My original 3 row round tube radiator has been replaced with a 5 row round tube Brassworks unit and now, after engine shut down, the car is thankfully silent and there is no sign of steam.

Eric.. thank you for your post we had similar experiences thanks

Scott.. your original radiator may have some rust deposits and tube blockage, it wouldn't hurt to find a reputable radiator shop to have it flushed out and serviced. Just a suggestion.

The fan plays little role in cooling the car except when running at very low speeds or sitting still with the motor running. Many Ts run with no fan. 250 F sounds a little high, but if the car isn't boiling, I wouldn't worry about it. The head temperature may actually increase for a few minutes after shutting the motor off after a drive. Parts of the engine, such as the exhaust valves, exhaust valve seat area, upper parts of the pistons, and the exhaust manifold run hotter than the rest of the engine, and heat from these areas will make its way to the cylinder head and upper radiator tank after the engine is stopped.

Most likely since this is an old radiator it has lost thermal connections to tubes. You need a new full size radiator.

250 is too high for my comfort. I draw the line at about 220 tops. Something is wrong.

Dan Hatch wrote: ↑

Fri Jul 08, 2022 2:20 pm

Most likely since this is an old radiator it has lost thermal connections to tubes. You need a new full size radiator.

After driving many years with a borderline 3 tube radiator and trying to have it repaired, I would back up what Dan says. I didn't realize just how "borderline" it was until I put in a new one.

Where I live the cost for replacing only the core was almost the same as a new radiator, so that made it pretty much a no-brainer. The kicker is that the overseas shipping and import fees run the cost up to around 50% more than it would cost in the USA, but in the end it makes for a nice cool running engine and no more spitting coolant on the windshield if I pull down hard on the throttle.

Hi Scott,

I have several records of thermoscans after running my 27 Tudor for a good drive. The highest I see on my records is 212 F at the top front of the head on a hot summer day. The top of the radiator just below the tank was 204 F and the bottom of the radiator was 157 F.

On fall days the same point on the top of the head was 187 F with the same radiator temps of 200 F and 145 F respectively.

Hope the helps with data your looking for.

Stu

Today, I drove it again. The temperature was 77. This time it has a water pump installed, but still the short pulley. The cylinder head temperature was right around 200 degrees. My next move is to install the longer pulley and install the short belt and not let the water pump turn. If it still runs cool, I will remove the pump. I did not check the radiator temperature at the top or the bottom.