1936 Pickup running hot!

[dan ia]

Hey guys, I am working on trying to finish up my '36 this summer! I have the engine in and running, it was a "Fresh" rebuild from about 20 years ago. It starts right up and runs very smooth, BUT it does run a little hot... I know that sometimes they will run a little hot after first start up while everything breaks in. The temp gauge will rise continuously until I finally shut off the engine. I took temperatures with a digital temp gun to make sure that the gauge isn't off... The highest that I got were readings around 180-190 all over the heads and the hoses as well, there were a couple of hot spots that reached 200-205, this seems hot to me. It has no thermostats in the hoses, the water pumps are the newer sealed bearing type, and I am running a 50/50 mixture of water and anti freeze. I know that this topic has been discussed to death, but I am looking for any help to try and get this truck to run cooler! Any help/ideas are certainly appreciated!!

[petehoovie]

Nice truck!!! Is this temp measured with the engine running stationary? Driving it down the road is a better test than stationary in your garage....

[tubman]

I had the engine in my O/T Corvette rebuilt about 15 years ago. It ran hot (just like yours) from the start. I could run around town and down the highway just fine, but let it idle more than a couple of minutes, and the temp gauge would start to rise...and rise...and rise. After about 800 miles of this, when I was just starting to think about pulling it and taking it back to the machine shop, it quit running hot. I think it was built "too tight" and had to wear in.

Bottom line, i would get it on the road and drive it. If it diesn't run hot driving around, it'll probably break in and be fine. Also, make sure your timing is right.

[drolston]

Timing retarded will contribute to overheat. With modern gas you can advance the timing. First check the vacuum brake on the distributor to be sure it has a little pressure with no vacuum, then use the adjustment on the side of the distributor to advance the spark. I would go full advance and then check it under load for pinging. If it pings, back off on the advance until it does not ping.

[dan ia]

Thanks for the replies! Yes, I am measuring stationary in my shop.. I did put 2 fans in front of it to try and simulate some air movement around the engine to try and help. I had the distributor and coil rebuilt at Bubba's, I didn't move any of the vacuum or timing since I got it back, I just bolted it on and runs smooth so I figured I was good. What is the best way to check my timing on this?? Thanks again!

[38bill]

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If your running the stock fan you will find that they don't pull very well while standing still. Even my truck that tends to run cold will start to heat up while stopped. I have an electric fan as well as the stock fan. Very rarely use the electric but its nice to have when I need it. Don't know much about the 36's but a fan shroud would help too.

[Talkwrench]

Theres nothing wrong with those temps, put 180 thermostats in. Cast iron should be running 180+ . 200 might be slightly high BUT hotter the better so long as it doesn't boil over..
Put temperature gauges in one in each head, dont be surprised if they are slightly different when running ..

[JSeery]

What Talkwrench said! And the engine would be a lot better off running it with a load on it until it is broken in. The rings will set better if it is driven, stationary running is not the best idea.

[petehoovie]

Originally Posted by JSeery

What Talkwrench said! And the engine would be a lot better off not run with a load on it until it is broken in. The rings will set better if it is driven, stationary running is not the best idea.

Did you mean to say "run with a load"

[petehoovie]

Oops! Repetitive post removed....

[JSeery]

Yes, Pete, I did. I have corrected that sentence 4 times now! I'm really having a difficult time being coherent today, LOL!!!

[Talkwrench]

Yeah how many times have I seen on Faceblah , guys that have videos of "first startup of my flathead " on engine stands and they let it idle.. give it a few revs and let it sit and idle away PFfT! ..
Get it in give it some..

[MGG]

What is the condition of the radiator? A clean one flows more water and cools better.

[Tinker]

Originally Posted by petehoovie

Nice truck!!! Is this temp measured with the engine running stationary? Driving it down the road is a better test than stationary in your garage....

yep. without some air flow who knows. Numbers sound fine.

[G.M.]

I have run 100's of heat tests in Florida on 90 degree or
warmer days. I use a 24" Lasko square box fan sitting on
the bumper and laying against the bottom of the grill.
With the fan on high, the radiator FILLED up in the filler
neck, plain water, 2 bottles of Purple Ice and 1 gallon of
Prestone perminate and a large bottle of Barr's stop leak,
the type with copper flakes. You need a 2 lb pressure cap
or a tight sealing early type cap. In order to get the early
caps to seal you need the drill the rivet out, cut a round flat
gasket out of the thin red rubber gasket material found in
the plumbing section of your local hardware store. Replace
the rivet with a stainless steel slotted 1/4 x 20 screw.3/4"
long with lock washer and nut, put a little lock-tite on the
threads. Run the engine at a speed equal to about 20 MPH.
If coolant come out the over flow make sure you don't have
a compression leak. After running for an hour or more shut
the engine down, DON"T remove cap and let sit over night,
the slight pressure in the system will force the stop leak into
any small pin hole leaks and seal them. The temp in this test
should not get over 195. Temp in these old Ford engines is
controlled by The amount of coolant in the system and the
gallons of coolant pumped through the system every 5 minutes.
Don't believe the story that the coolant is going through the
engine to fast. Modern and reproduction pumps move 55 to
65 gallons off coolant through the engine every 5 minutes,
Skips modified pumps move 110 gallons every 5 minutes.
The cooling effect can be measured with a laser pointed
temperature gun at the bottom and about 4"s from the top
of the radiator. We also notice on the water pump test machine
which is a sealed closed circuit the same as the radiator that
after a 5 minute test run of a pump that when the cap is
released there is very little air in the system compared to a
stock pump. This is due to the fact the impeller and it's tight
controlled clearance with the seat is pushing water and not
slipping in water making air. When the cap is released with
a stock pump there is a gush of air and on Skips pumps there
is hardly any air. A clean block, heads and radiator are required
for good heat transfer. This is not intended to be an add for
Skip, just the true facts found after over 20 years of rebuilding
Ford pumps. Read the results posted of people using Skips
pumps and they tell the real story. G.M.

[dan ia]

Thanks, I have had the radiator cleaned and re cored so that shouldn't be a problem. I have thought about sending my pumps down to skip to have them rebuilt just because I have read that his are the best. I have looked, but cannot find thermostats that will fit in this engine, what is everyone else using for this? Or am I better just leaving without thermostats? Also, what are you guys using for temp gauges?? I am thinking it would be nice to have a gauge with actual temp readings on it. Thanks again for all your help! Keep it coming!!

[G.M.]

Originally Posted by dan ia

Thanks, I have had the radiator cleaned and re cored so that shouldn't be a problem. I have thought about sending my pumps down to skip to have them rebuilt just because I have read that his are the best. I have looked, but cannot find thermostats that will fit in this engine, what is everyone else using for this? Or am I better just leaving without thermostats? Also, what are you guys using for temp gauges?? I am thinking it would be nice to have a gauge with actual temp readings on it. Thanks again for all your help! Keep it coming!!

We use a hand held laser pointed temp gun. From this you can see
where the gauges read. The best thing is to run with no thermostats
until you see the temperatures, stats don't help with cooling, just make
the engine run hotter. The best thermostats fit into the upper radiator
hoses. Bob Shewman in Kimberton, Pa. make stats that fit in the hoses.
Bobs phone number is 1-610-933-6637 Beware of stats with small flow
opening, these restrict the flow of coolant through the engine. G.M.