1972 CAT D4D overheating

[Fixingfarmer]

So if thermostat is done I’d still suggest cleaning those cores as good as possible. Then going at the water pump it’s going to be kinda spendy you don’t want to throw a 1000 dollar pump in and find out you need to clean the cores at the end. I think you are right pump is where this is headed. But I have seen a lot come out of what was thought to be a clean radiator. And it help significantly

 

[Fixingfarmer]

And yes this should be gear driven pump on the rh side I believe even this early not belt drive. I’m going to suggest the reman pump since this working at idle and intermittent at full throttle it could be a loose impeller or fins worn down something of that nature. I mean you can rebuild it if you have a press and want to take some time at it but it’s going to be beefy the kits aren’t cheap and you can find complete new ones for not a whole lot more I’m betting the shaft and impellers going to be around 300 dollars plus seals and bearings. You don’t want to mess up with an internal bearing like that the balls can do some crazy damage to the front drive train.

 

[Jerry/MT]

Yep, it’s gear driven.
I really hope that it’s just the water pump. This would be an easy fix.
I’m about to remove it now.

Ebay has the pump rebuild kits ( ~ $40) and remanufactured pumps, (~ $175) IIRC

 

[Fixingfarmer]

If your lucky there should be a part number on the pump

 

[Greenfielrider]

So if thermostat is done I’d still suggest cleaning those cores as good as possible. Then going at the water pump it’s going to be kinda spendy you don’t want to throw a 1000 dollar pump in and find out you need to clean the cores at the end. I think you are right pump is where this is headed. But I have seen a lot come out of what was thought to be a clean radiator. And it help

From what I see, the radiator core is not very clean but it looks similar to the radiator of one of my other tractors, which is not overheating.

But if the radiator core is dirty/clogged, wouldn’t the temperature difference between the top and bottom hose be much less, for example, just 10°F or so?

 

[Greenfielrider]

View attachment IMG_8743.jpeg

Soooo… the water pump is off.
What do you guys think about the impeller? It looks good to me but I have nothing to compare it to.

IMO, the oil seal “behind” the impeller failed. The oil in there looked contaminated with water (it’s milky) and plenty of rusty gunk behind and in this seal. The two (?) bearing don’t look to too bad.

The bolt that holds the impeller in place wasn’t loose but it also wasn’t super super tight, so maybe the impeller slipped?

 

[Jerry/MT]

View attachment 3661

Soooo… the water pump is off.
What do you guys think about the impeller? It looks good to me but I have nothing to compare it to.

IMO, the oil seal “behind” the impeller failed. The oil in there looked contaminated with water (it’s milky) and plenty of rusty gunk behind and in this seal. The two (?) bearing don’t look to too bad.

The bolt that holds the impeller in place wasn’t loose but it also wasn’t super super tight, so maybe the impeller slipped?

Is the impeller keyed to the shaft? Is there anything to limit the impeller from slipping on the shaft? The impeller itself looks good in that picture. How's the end play?

 

[Greenfielrider]

Is the impeller keyed to the shaft? Is there anything to limit the impeller from slipping on the shaft? The impeller itself looks good in that picture. How's the end play?

No it’s not keyed to the shaft. It’s just bolted on the shaft. So beside the bolt, there is nothing that limits the impeller from slipping on the shaft. There could be a tiny tiny bit of end play.

 

[Fixingfarmer]

From what I see, the radiator core is not very clean but it looks similar to the radiator of one of my other tractors, which is not overheating.

But if the radiator core is dirty/clogged, wouldn’t the temperature difference between the top and bottom hose be much less, for example, just 10°F or so?

Oh it can cause overheating pretty bad if the radiator is plugged it can get up to 230 or worse if not paid attention too.

 

[Fixingfarmer]

So there should be a key I think also I thought those impellers had a flat disk part to the back of them. Is this a belt drive?

 

[Greenfielrider]

Oh it can cause overheating pretty bad if the radiator is plugged it can get up to 230 or worse if not paid attention too.

No I mean the temperature differential between the top and the bottom hose of the radiator. So the radiator inlet and outlet. I measured a temperature differential of 30-40F.
Which I thought is good?

Is there any way to clean the radiator without removing it?
Besides that I have no idea how to remove it, it looks like a major pita to get that thing off the dozer. Let alone to remove all those rusted bolts to get the core out.

230 is pretty much what I have if I don’t pay attention…. Couple more of those test runs and at some point I will also need a new head gasket…

 

[Greenfielrider]

So there should be a key I think also I thought those impellers had a flat disk part to the back of them. Is this a belt drive?

Yes, there is a key on the shaft that holds the gear in place.

 

[AJ.]

That sounds like the radiator is not doing its job. There can be many things that can cause overheating. if the radiator core is blocked internally or externally it can cause the problem you are having, check the difference of the temperature of the bottom and top of the radiator, hot coolant from the engine enters the rad at the top and is pushed by the pump out the bottom after it has been cooled by the fan, there should be 10/12 degrees difference between the top and the bottom,.there are other things that can cause overheating like cracked head, precombustion chamber loose, cracked liner, whats the history of the machine.
AJ

 

[Greenfielrider]

That sounds like the radiator is not doing its job. There can be many things that can cause overheating. if the radiator core is blocked internally or externally it can cause the problem you are having, check the difference of the temperature of the bottom and top of the radiator, hot coolant from the engine enters the rad at the top and is pushed by the pump out the bottom after it has been cooled by the fan, there should be 10/12 degrees difference between the top and the bottom,.there are other things that can cause overheating like cracked head, precombustion chamber loose, cracked liner, whats the history of the machine.
AJ

The temperature differential is 38 degrees.

 

[AJ.]

That's ok, next engine warm and on low idle remove the radiator filler cap, (protect your hands), watch the coolant for any sign of air bubbles coming up through it, how is the oil is it clean and the level not rising, do you know if it's a 3304 engine it has, is it manual or power shift.
AJ

 

[Greenfielrider]

That's ok, next engine warm and on low idle remove the radiator filler cap, (protect your hands), watch the coolant for any sign of air bubbles coming up through it, how is the oil is it clean and the level not rising, do you know if it's a 3304 engine it has, is it manual or power shift.
AJ

No air bubbles when warm.
The oil is dark brown and the level is not rising. No oil in the water or water in the oil.
As far as I know it’s a 3304 engine with power shift.

 

[Fixingfarmer]

How dark brown are we talking. Reddish? If you have a sample bottle take one

 

[Greenfielrider]

How dark brown are we talking. Reddish? If you have a sample bottle take one

Its closer to black than red. Depending on the light a very dark brown or some shade of black. Photo attached.

 

[Fixingfarmer]

Yeah that seems fine you could sample it for 14 bucks just to make sure at caterpillar see if there’s any water or ethylene glycol in it

 

[AJ.]

Your problem is more than likely the same problem as why the machine was parked in the first place, there has to be a reason it was parked, those were great dozers but were prone to the liners coming loose and the heads cracking should they get hot and have cold water poured in. have a Cat mechanic look at it for you..
AJ