1975 Ford 4100 overheating

[DavidTT]

I have a 1975 Ford 4100 diesel that gradually started overheating. It mostly started overheating when i was working it hard, then started heating more even when not working it as hard. I noticed the anti freeze was very rusty, so i flushed it several times. I seen cooling fins were a little stopped up, so i cleaned them real good. I replaced the thermostat, and it is still heating up. I have taken the radiator off thinking maybe i can get it cleaned out? But seems like water is flowing very good through it. Any suggestions?

 

[Janicholson]

Welcome to YT forums and PartsASAP
Water pumps can become very ineffective over time. The impeller fins deteriorate. Also radiator hoses can fail internally causing stoppage that is tough to detect. Hand held laser aimed thermometers are good for that issue and others. Combustion gsses in coolant can be checked with a kit from an autoparts store. Jim

 

[casecollectorsc]

Fan belt and pulleys in good shape and tight??

 

[DavidTT]

Fan belt and pulleys look good and tight. no wobble, no leaks. I thought about replacing water pump.

 

[DavidTT]

My radiator hoses are not brittle or dry rotted, so i am not sure what you mean about a hose failing internally?

Thank you for the responses.

 

[rustred]

I have a 1975 Ford 4100 diesel that gradually started overheating. It mostly started overheating when i was working it hard, then started heating more even when not working it as hard. I noticed the anti freeze was very rusty, so i flushed it several times. I seen cooling fins were a little stopped up, so i cleaned them real good. I replaced the thermostat, and it is still heating up. I have taken the radiator off thinking maybe i can get it cleaned out? But seems like water is flowing very good through it. Any suggestions?

Rad shop and hot tank time. Your not going to tell just by running water through it the cores will be plugged farther down than u can see.

 

[DavidTT]

10-4, will do. Wonder if i should replace water pump while radiator is out

 

[sotxbill]

10-4, will do. Wonder if i should replace water pump while radiator is out

I would replace the pump while its out.. much much much easier now than later.

BUt have you checked the radiator for bubbles while running?? If you can see bubbles while looking in the top, its a blown head gasket or worse and it WILL overheat. If bad enough, the oil may/will/can turn a whitish grey color ..

Are the cooling fins clear and not blocked with dirt and mud.. even oil from the oil bath air cleaner splashes out and onto the radiator fins, making dirt stick and clog.... especially if running over rough/bumpy fields.(if diesel)

 

[will-max dairy]

Just for fun... or curiosity... park the machine overnight on level ground. Before you start it, go to your oil pan, put a catch pan under the drain plug... then take a wrench and carefully turn the drain plug loose and stop when it drips about one drop per second.

Let it drip at that rate for a minute or so. Then look at the catch pan. Any coolant there?

(the working idea behind this is that coolant is both heavier and less viscous than engine oil... if there is any coolant in your engine oil, it will settle to the bottom, it will also start to drip from the drain plug fairly easily when you loosen it just a little)

Tell us here what the results of that are.

 

[Janicholson]

My radiator hoses are not brittle or dry rotted, so i am not sure what you mean about a hose failing internally?

Thank you for the responses.

The external look of a hose can disguise an internal fault. A flap of hose liner can split loose and act like a heart valve stopping or limiting flow. I have seen it several times in engine coolant systems, once in a garden hose, and several times in hydraulic hoses. Jim

 

[Mule Meat]

My radiator hoses are not brittle or dry rotted, so i am not sure what you mean about a hose failing internally?

Thank you for the responses.

Radiator hoses are made in layers.
The outside of a hose can look good. But the inside can separate and block coolant flow. It mainly happens on the pump inlet side where vacuum is created. If entire hose can collapse from vacuum blocking flow on hoses that have become weak.. You can get lower radiator hoses that have a coil spring like wire in them that prevents collapsing.

If you are shelling out for a new pump. You should go ahead and install new houses and thermostat while you have it down.

 

[sotxbill]

Radiator hoses are made in layers.
The outside of a hose can look good. But the inside can separate and block coolant flow. It mainly happens on the pump inlet side where vacuum is created. If entire hose can collapse from vacuum blocking flow on hoses that have become weak.. You can get lower radiator hoses that have a coil spring like wire in them that prevents collapsing.

If you are shelling out for a new pump. You should go ahead and install new houses and thermostat while you have it down.

I have the seen lower hose being sucked mostly closed at higher rpms... creating a mild to moderate over heating problem.. First off these are chinesium hoses and are very soft and squeezeable vs the better made hoses that are rigid. (Dont Squeeze the Charmin)

Some bottom hoses even had anti- collapse springs in them... of which.. you can still order the springs from summit racing.. for the bottom hoses. I still have a couple in the garage somewhere.

 

[DavidTT]

I have my radiator at a shop for getting checked out and cleaned out. I haven't looked at the radiator bubbles while its running. The oil is not milky looking either. I do have a lot of blow by coming out the blow by tube, which i was told don't worry about it, run it. That was several years ago though. One time about 5 years ago, it wasn't running right, changed the fuel filter, couldn't get it started, so me and my uncle sprayed it with either and locked it it up. Had to get the head reworked , which i would think a new head gasket was put on.

Thanks for the responses.... When i get the results of the radiator i will let yall know.....

 

[rustred]

you must not have had the filters bled properly. starting fluid should be sprayed in with just a short mist, and cranking it over at the same time is the best.

 

[DavidTT]

i am still waiting on radiator shop with their findings right now. I will keep yall posted. Thanks

 

[DavidTT]

OK, update. The radiator shop said my radiator was shot. So I ordered a radiator and water pump. I flushed the block out, installed new radiator, new water pump, new thermostat. Ran it today and it overheated even more so than before???. I took the new thermostat back out and put it in hot water just to make sure i didn't get a bad one. I didn't replace the hoses. And I don't know if I had the air hole on the thermostat pointed upward not, I didn't purposely set it that way. I guess i will buy new hoses and try that??? I am just thinking if a head gasket is blown, would it pressurize the water jackets and prevent water from circulating? How would i check for that? Bubbles in radiator? I haven't noticed that. Nor have i noticed water in oil. Any comments would be greatly appreciated. Thank you

 

[Rystoltenberg11]

If there’s no water in the oil, it’s not the head gasket. Replace the hoses then keep us posted

 

[rustred]

OK, update. The radiator shop said my radiator was shot. So I ordered a radiator and water pump. I flushed the block out, installed new radiator, new water pump, new thermostat. Ran it today and it overheated even more so than before???. I took the new thermostat back out and put it in hot water just to make sure i didn't get a bad one. I didn't replace the hoses. And I don't know if I had the air hole on the thermostat pointed upward not, I didn't purposely set it that way. I guess i will buy new hoses and try that??? I am just thinking if a head gasket is blown, would it pressurize the water jackets and prevent water from circulating? How would i check for that? Bubbles in radiator? I haven't noticed that. Nor have i noticed water in oil. Any comments would be greatly appreciated. Thank you

The spring on the stat goes down or towards engine block not up. Good possibly u have it upside down and that’s will make it heat. Why buy hoses check the first by removing them. If the they are soft and mushy the bottom hose can colapse. Plus feel the hoses when it running. If the bottom one is cold then the coolant is not circulating. U can have a created problem. As for the head gasket u will see bubbles coming when the rad is filled to the top. Plus be blowing out the coolant. So some checks to do.

 

[rustred]

The spring on the stat goes down or towards engine block not up. Good possibly u have it upside down and that’s will make it heat. Why buy hoses check the first by removing them. If the they are soft and mushy the bottom hose can colapse. Plus feel the hoses when it running. If the bottom one is cold then the coolant is not circulating. U can have a created problem. As for the head gasket u will see bubbles coming when the rad is filled to the top. Plus be blowing out the coolant. So some checks to do.

Plus u can just remove the stat and see what happens. The coolant will be glowing good then plus many times there is a spring in the lower rad hose to keep it from collapsing. Why replace parts for no reason ? .

 

[Phill Tibbetts]

Sounds like the radiator shop ripped you off, no surprise.