VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1937-1945 40 Overheating Saga Continues, Ideas?

Over the past few months installed new radiator, auxiliary electric fan and Evans coolant to improve overheating in traffic/stoplights. Unfortunately, not the results I had hoped for. Took her out for a spin on a high 80s afternoon and temp gauge pegged. Back in the garage, with engine at idle and auxiliary fan running, quickly popped the hood and had these measurements with infrared gun: Thermostat housing, 192, Radiator inlet neck 169, Radiator outlet neck 120. Cylinder Head at temp. sending unit 270, 2 inches to right of sending unit 280, 2 inches to left of sending unit 225 degrees. Seems like Radiator functioning and there is a circulation problem at the rear of the head. The 216 is 1953 block. Possible wrong head from another year in use? Are there serial numbers on heads to identify year? Perhaps all 216 heads are interchangeable and that's not the problem? Perhaps the likely problem is rust scaling in head water passage? Other things to consider or further test to be done? Suggestions on next steps? Thanks.

The head casting number is under the valve cover to the left side.
Actually any 216 head WILL WORK BUT A 1937-1940 HEAD WILL GIVE A VERY LOW COMPRESSION RATIO DUE TO THE FACT IT WAS DESIGNED FOR DOMED PISTIONS.
Is the power up to par, timing retardd, exhaust restricted or perhaps a bad head gasket?
erhaps an impeller problem with the waterpump. Or a 1q940 one hle water pump on a later two hole pump engine.

I agree that the high temperatures in the rear of the head indicate a major circulation problem, most likely due to scale build-up in the block.

My experience is that there is no quick or simple solution. The head has to come off and the core (frost) plugs have to come out so you can dig all that scale out of the block.

There are some people who have had success with Evaporust. Do a search here on Chat.

I would start by heeding what Gene said.
Pull the water pump off first, as it isn't too hard to do.
Make sure the impeller is tight on the shaft, and that you have the right pump.

That will also let you see into the block (probably need a mirror) to look for scale and crud.
If you see crud there, there's probably a LOT more in the back end.

Hope you find the problem at the pump, as that would be the easiest fix!

If I remember correctly he has a rebuilt engine.
f you remove the entire pet cock from the block water should runout - may enev take a little probing with a coat hanger wire to do so.

Thermostat stuck shut?

I really appreciate all the discussion. A lot to think about. Some of my thoughts at the moment. With the new radiator, a new thermostat went in. Car runs great going down the road at reasonable temps, accelerates fine and cruises easily, it is heavy traffic and stop lights where the temps begin to soar, and in the garage when engine is turned off. Radiator temp and thermostat housing temp readings seem in a descent range when the rear of the head is 270-280. Of course if the decision is to take off the block, remove frost plugs and pet cock, it would make sense to take a close look at the water pump. Perhaps I should get it hot again and take more temp readings around the block to see if they shed in further light on other hot spots. The Evaporust I'll need to learn more about. From what little I know, I wonder if that is the best solution, assuming scaling. Are there temperature reading locations that would tell more about where the blockages are in the block or in the head or indicate a pump problem? The head gasket thought of Gene's makes me wonder but no sign of coolant in the sump, and again she runs fine at speed. Don't know what to think.

Hi 40ragtop

We had a water pump impeller come loose and spin free on a brand new JD 7330 tractor under warranty.
It was diagnosed by a technician who noted that half the engine was near normal temperature, while the other half was hot, sending the gauge into the red, and setting off buzzers.

So... I'd still start with the water pump.
With a poorly functioning pump, the front of the engine will "thermosyphon" to some degree, but the rear will run much hotter.

Good luck

PS
To look at the water pump, you'll need to drain the coolant, which means you'll be pulling out the drain cock at the rear of the block as per Gene above.
So you will be following Gene's suggestion first, which is good.
And you just may find your whole problem right there.

If coolant doesnt flow when you remove the petcock and need to wriggle wire to get a flow I would near bet you will be pulling the core plugs.
Tony

Hi Tony

Mine didn't flow when I drained the block after I bought the truck.
But it was soft sludgy stuff that came out when I poked around with a wire.
I didn't need to remove plugs, but it did take quite a bit of flushing and poking around.

that isnt a good sign though not as bad as some I have seen. It might still be a good idea to do the core plug clean even though it is a lot of work.
Tony

I haven't been able to reach my mechanic yet to get his input into our discussion, but hope to do so soon. That said, I do recall Tom telling me about the process of switching over to Evans coolant and I believe it was a several step process of draining coolant, installing a pre-mix to circulate in the system, then flushing a lot and then add the final coolant. Hope to hear more about how the block drained and how the various flushing efforts went with liquid flowing from the block. Will report back. In the meantime, I'm curious about the high temps in the head at the temp. sending unit and near to it. I'm thinking the problem might be more in the head, although coolant does circulate through the radiator. Tom also examined the water pump, although did not remove it, and concluded that it was functioning well with no leaks. Assuming next steps are to remove the head, freeze plugs and petcock to attack the rust, what tools/process would be used to clean block and head?

Digging the crud out of a block and head is just a lot of manual work. Screwdrivers and heavy coat hanger wires with a shop vac seem to be the most effective method.

I was very fortunate on my '37. The crud was more sludge that rust scale. I made 3 adapters so i could flush water through the block in 3 different patterns.

- One adapter allowed me to connect a garden hose to the water outlet housing on the front of the head. Obviously I had removed the thermostat.
- One adapter connected to the drain hole at the rear of the block.
- The third one was a plate with a bulkhead fitting that fit over the front of the block where the water pump mounts.

With those 3 adapters I could force water through the block in 3 different directions. I could connect the garden hose to one adapter, connect a drain to another, and block the third.

I never had overheating issues. The temperature at the sending unit was about 10 degrees hotter that at the thermostat which is normal for these engines. I ran a 160 degree thermostat and the temperature gauge and my IR gun read 170 at the sender.

Rust, thanks for the very helpful above "how to" info. Could you post photos of your adapters whenever time permits? Wow, you had 170 at the temp sender....tells me how seriously bad my temps are. Would the temp sending unit head casting be a useful point to scrape a coat hanger through the rear of the head do you think?

Try this:

Remove the upper hose by taking off the thermostat housing. This will let you remove the thermostat and the upper inlet hose. Now trip the belt off the generator, crank and water pump. Having done this replace thermostat housing and fil the engine with water. Garden hose whatever. Now have some one start the engine and see if you get bubbles up through the thermostat housing. If you do and they are big bubbles then you have blown head gasket. If small, tiny bubbles then it may be coming from a cracked head or block.

While you are at it, take a high pressure air source and blow back through the block at the plug on the lower left side of the engine block (with water ever present in the thermostat housing) until the water coming out of the plug hole runs clear. Using a coat hanger wire to fiddle around in the block may help some.

Even though the Harrison radiator is new the flues are not raised like a Ford (Cord) radiator and can get sludgedup real easily. So take the bottom hose off and blow back up through the radiator to get as much rust and junk out as you can. Check the water pump by replacing the belt and starting the engine with water to the top of the thermostat housing. If the water moves and the pump is not leaking through the bottom hole of it and is there for that purpose then the the pump is okay. The impeller seldom fails by coming loose on the shaft. Pumps are simple and seldom give problems other than leaking coolant after many miles of use.

Hope this helps.

BTW: It may be wise to check the thermostat by putting it in a pot if water and with a thermometer checking to see that it opens at the temperature indicated on it. Generally, thermostats give the worst problem when they stick in the closed position. A good working thermostat lets coolant flow when it reaches the designed temperature, When they are working properly the merely regulate the flow of coolant until they reach full opening. Nothing beyond that.

Hope you get the problems sorted out soon. Don't go a buy a new water pump unless you really need one.

Best,

Charlie

Well, my mechanic is back and we've had long discussions about all of the above input but one question lingers with him: "Is a temp reading of 290 degrees on the head/sending unit a serious problem?" He feels like the area of the sending unit being so near to the exhaust manifold that it is logical that it would be hotter than other areas, so he questions how big a problem this is. I have pointed out Rusty's experience of 170 degrees at the sending unit as a comparison. Could my 40 and Rusty's 37 be that much different? Can "normal" head temperatures range this high in 216s?

The readings that I took were with the laser beam from the IR gun pointed on the fitting that screws into the head. I agree that if you are measuring the head temperature itself near the exhaust manifold you will get a higher reading. My thinking is that the temperature of that fitting should be similar to the body of the sending unit That is what the gauge is reading.

We get similar readings to those from my '37 in my friend's '49 pickup which has a 216 from a 1951 car.

Have you measured the head temperature at different locations from front to rear?

I've had a heating issue for sometime and discovered in both situations that it was water not completely filling the water passages. I now first fill the block through the hole where the temp sensor goes. It seems to have stopped the problem.... And as always,you never know....

As to the Laser iR gun, the red dot produced is only used to help you point it. The laser does nothing. There are IR sensors in the gun that try to measure the heat where the dot indicates. If you put the red dot on something near the manifold when it's hot, it will average the heat over the entire area not just where the dot is. And if you aim it at the head and the manifold is there, it will give you the temp of the manifold or the hotist thing that's close...... Just saying.... If you want to measure the water temp, measure the water.

Mike

290 Deg. confirmed that no coolant is getting to that area.It should read about the same as the dash gauge and is the warmest area in the system, that is why they put the sensor at that location. HAVE YOU TRIED REMOVING IT? iF YOU DO WATER SHOULR RUSH OUT.\
i AM THINKING THE PASSAGES IN THE HEAD AND BLOCKED and COMPLETELY RESTRICTED. iF IT WERE MINE THE FIRST TING i WOULD DO IS REMOVE THE HEAD,......if you havve determned that the WATER PUMP IS ok.

As always thanks for the input. Did some more temp measures while hot. Sending unit: Sending unit brass fitting top was 207, on head at sending unit 290, to the rear of sending unit on head 260, on head 2 inches forward of unit 221. Temps on the head, above intake manifold ports, starting from the rear port, 222, 216, 208.

Thinking of Mike's comments (which I read after taking the above temps). Would temp readings be more correct the closer the ir gun is to the measuring point? I haven't been reaching in close but holding the gun 2 feet or so away.

Temps on the head cover panel, other side of engine, measured about 2 inches to the side of each plug from the rear: 164,164,158,162, 156, 154. All temps with engine at hot idle.

I don't know the sensing field .... If it's a cone, the closer you get the more precise, if it's a cylinder it prob doesn't matter much...... Being that they are usually inexpensive, I suspect that they are not precise and just average out the heat....

There are contact sensors that only read what they touch....

Mike

IR sensors are infamous for being inaccurate. They just give one a guideline showing one area is hotter or colder than another. The exact temps displayed are usually inaccurate from what I've read and heard.

how about the tension on the fan belt? It does not have to make noise when slipping just enough to slow the pump down, have had this happen to me a few times, retightened the belt and my overheating problems went away.

How about hooking up a water hose, in and out, and bypass the radiator/heater. You can then check the water temp coming out (shouldn't be much different) and then check the block for hotspots and/or possible blockages.... If there is a blockage, it should show up as a diff in temp...

Also, make sure that the area around the temp sensor has water...... As Chev Nut says...

Just thinking....

Mike

While I agree that IR guns are not the most accurate method to measure temperature, they do work well when the operator understands the concepts of distance to spot center diameter ratio and emissivity.

An IR gun reads the amount of heat being radiated from a surface and then translates that to an estimate of surface temperature.

My gun from Harbor Freight has a 12:1 distance to spot center diameter ratio. That means when I hold the lens of gun 12" from a surface, it is reading the heat being radiated from a 1" diameter circle.

Emissivity is the amount of thermal energy being radiated from a surface. Dark surfaces have high emissivity and shiny surface such as aluminum have low emissivity. Dirt tends to create higher emissivity. I can adjust the emissivity factor on my gun.

Having said all this, the readings that ragtop40 has presented show a real problem with coolant circulation in the head and block.

The readings you got from the side cover on the right side of the engine are very realistic. There is probably at least a 3/8" air gap between the side of the block and that cover. sheet metal cover. So it will never get as hot as the head or block. The readings you got from the front end of the engine and radiator are realistic. So why are the readings at the rear of the head not realistic?

if the temperature gauge in the car is accurate (you can test it with hot water), then coolant is boiling at the back of the block and head. Vapor will not transfer heat.

Interesting!!!

Good point in the IR guns.

Mike