D6D engine overheating

[DD57]

I think you are getting combustion gasses in the cooling system. I would clean that radiator/cooler assembly, and put it carefully back in the dozer. It should not be blowing the coolant out the radiator.Those cylinder gasses are so hot,and under such pressure, when they enter the cooling system, it gets hot fast. If your lucky,you may just have a loose pre-combustion chamber. Good Luck with that,its a nice clean looking machine.If you run it without all those attachments,on it, does it still overheat?

 

[.RC.]

Yea possibly, but it only does it when the radiator is topped up full to the brim and there is no room for expansion. Then only it pops out water once or twice as it heats up, then the level remains stable a couple of inches down from the top.

I had a bit of time so got out the 9" angle grinder onto the TC cooler

Well actually it was only a 5" with thin cut off wheel and then a dremel with a tiny cut off wheel to tidy things up. Looks like it will work a treat on the damaged fins. I can see daylight through it where none existed before. Especially after I blew it out. and it is surprisingly quick to do.

 

[OzDozer]

You know of course, that a Cat engineer is now going to tell you, you just reduced your cooling capacity by 5%, by cutting back all those fins?

 

[Shimmy1]

I'm just going to make a couple of "observations", I know I'm probably nowhere near qualified to respond on this thread.

Are you ABSOLUTELY certain that the temp drop through the radiator is affected by the radiator, and not flow? Like maybe a smaller restriction could be tried to slow flow down more?

Has the overhead been ran recently? Apologies if I missed it in the thread, I just browsed through it.

Do we know if the fuel pump has ever been messed with? Timing OR fuel delivery? Again, if this has been mentioned, tell me to go sit in the corner.

Lastly, is the exhaust system been eliminated as a perp? I had a muffler on a truck with the baffle broke free and created a pretty substantial restriction in the exhaust causing high exhaust temps and ultimately high coolant temps. That muffler appears to be beat to ****. Food for thought.

 

[Welder Dave]

There is very recent post of an excavator with a bad muffler that cooked the seals on the hyd. tank causing loss of (tank) pressure and pump cavitation. Bad or damaged muffler or exhaust pipe leaks could put a lot of excess heat under the hood.

 

[.RC.]

I'm just going to make a couple of "observations", I know I'm probably nowhere near qualified to respond on this thread.

Are you ABSOLUTELY certain that the temp drop through the radiator is affected by the radiator, and not flow? Like maybe a smaller restriction could be tried to slow flow down more?

Has the overhead been ran recently? Apologies if I missed it in the thread, I just browsed through it.

Do we know if the fuel pump has ever been messed with? Timing OR fuel delivery? Again, if this has been mentioned, tell me to go sit in the corner.

Lastly, is the exhaust system been eliminated as a perp? I had a muffler on a truck with the baffle broke free and created a pretty substantial restriction in the exhaust causing high exhaust temps and ultimately high coolant temps. That muffler appears to be beat to ****. Food for thought.

We know with certainty the radiator is wrong. In my research I found this, pretty much the same machine with the same heating issue and a similar low fin count radiator. https://www.heavyequipmentforums.com/threads/operating-temp-d6c.77931/page-2. While there was no resolution there, there was another thread for the same machine a couple of years later.
while again no resolution, the radiator was replaced with a proper one. https://www.heavyequipmentforums.com/threads/cat-parts-manual-gives-wrong-part.94689/

I can say the engine has not been turned up. It drives like every other Caterpillar dozer of that era. they were never renowned for being able to win any 1/4 mile races, only endurance races.

Muffler is clean. Could be timing.

At least this should let a bit more air flow through. If I had the skills, I would debraze the top and bottom tanks and simply spin it around. The fins on the other side are near perfect still. But I am not up to Pakistani truck rebuilders skill level yet.

 

[.RC.]

This one is for Nige.

 

[Nige]

Can you see the difference between what you have now and what you had then.? Do the new belts look the same in all the pulleys.?

You probably don’t have a phototach but I’m willing to bet that new belts are probably giving you a decent increase in fan speed - although with the condition of the radiator and the oil cooler it probably makes no difference to system performance in the grand scheme of things.

BTW did you get that document I sent to you regarding cooling systems.?

 

[.RC.]

Yes the belts ride high in all the pulleys now. The radiator core is currently at the radiator shop getting measured for a new core. The only two local producers of radiator cores both copied each other and make then at 6.5fpi,o I have to get a special order one made.

 

[D6 Merv]

re the oil to air torque converter cooler, only gets oil sent to it after the cooler bypass valve opens.
Is same function as a thermostat. If your torque converter oil temp was rising before the engine temp, consequently putting all its heat into the oil to water system. Bypass valve could be faulty. Mind you this is easy checked by putting a hand on cooler pipes to oil to air cooler. If they are cold or warm. Cooler bypass valve is meant to open at 85 C oil temp
The new radiator core i put in my earlier PC engine D6D, same as yours, had the wider spaced fins in it compared to the closer space fins original one that came out of it. New core solved all the problems i was having with it. And no troubles since

 

[.RC.]

The bypass valve seems to be working Merv. I am also not surprised in your climate a lower fin count radiator would be fine. It works fine here in winter, which would be similar to your summer.

 

[.RC.]

New radiator core is ordered and getting built. Have got the required gaskets waiting to be picked up. Do people normally use gasket goo on radiator gaskets just to make sure they do not leak?

 

[56wrench]

Ya

 

[.RC.]

Yes, after pulling the tanks apart, I will be using gasket goo.

Someone has made up a "spacer" plate and soldered it onto both tanks. Looks to have been a few rust repairs done. I half expected the tanks to be cast iron, but they are just pressed sheet steel. I would imagine like all old machines back in the day no one used rust inhibitor in the coolant.

The filler cap was done up so tight I had to use stilsons to undo it. I have seen that before as the sealing portion is corroded and rather then fix it, it just gets done up tighter. I brazed and machined it back flat. Not too impressed with the chatter marks but it was to be expected.

 

[Welder Dave]

Could you smooth it out with a file?

 

[The old Cat man]

So I have come to the conclusion my D6D has a cooling problem. It is not a dire cooling problem but it renders the machine unusable for longer periods in summer. The problem is I am pretty sure not in the transmission as it never gets any further then 3/4 of the way through the green, even when the engine reaches the red. The engine will not start running hot until the torque converter gets at least 1/3rd into the green which takes an hour or more. Then if I load the engine up, the temperature it will slowly creep up to the red.

It has done this ever since I bought it a couple of years ago. If I look at the machine I can see the following has been replaced. Transmission water cooler and the transmission radiator cooler, the fan belts are tight and the pulleys are new. The water pump also lacks paint so I suspect it also is new. I pulled the thermostat and checked it and it is fine. The only thing not checked in the engine timing, which I have heard can cause heating issues.

Which leads me to think I know what the problem is. The radiator core which has also recently been replaced. I have flushed it and washed it to no avail, however what I noticed is that the core they used has mighty big gaps between the fins so I looked up the core details which led me to an Australian manufacturer of cores and they list this core as having 6.5 fins per inch, while nearly every other radiator core they make for cat machines lists 9 fins per inch and they list a lot of cores.

So does is sound feasible that they installed a core that the manufacturer puts in the incorrect number of fins for the application, most of the air getting blown through does nothing as it goes no where near the fins.

The core is a 4N6298

I have heard of the water pump impeller coming loose. It pretty easy to check you just need to drain antifreeze and remove the water pump cover to gain access to the impeller Also if you’re you can get a hand infra red temp gun and check the temp of the top rad tank and the bottom tank, there should be 10 degrees difference with engine warm and running. If you have more than 10 degrees means plugged rad. Externally. If you have less than 10 then it’s plugged internally or other circulation problems

 

[AllDodge]

Most cases you can remove one of the water pump hoses and stick a thin screw driver or stiff wire into the impeller. Then turn the pump and see if the wire can stop it

 

[Welder Dave]

I have heard of the water pump impeller coming loose. It pretty easy to check you just need to drain antifreeze and remove the water pump cover to gain access to the impeller Also if you’re you can get a hand infra red temp gun and check the temp of the top rad tank and the bottom tank, there should be 10 degrees difference with engine warm and running. If you have more than 10 degrees means plugged rad. Externally. If you have less than 10 then it’s plugged internally or other circulation problems

Welcome to the forum. You're not too far from my property. It's just past Sturgeon County in Thorhild County West of Opal.

 

[.RC.]

Could you smooth it out with a file?

Nah, just redo it with a sharper cutter. If I knew how to tig weld it would have made it a lot betterer. I still have one part of exposed cast iron as I found it difficult to build it up with the oxy, it would just stay flat.

I have heard of the water pump impeller coming loose. It pretty easy to check you just need to drain antifreeze and remove the water pump cover to gain access to the impeller Also if you’re you can get a hand infra red temp gun and check the temp of the top rad tank and the bottom tank, there should be 10 degrees difference with engine warm and running. If you have more than 10 degrees means plugged rad. Externally. If you have less than 10 then it’s plugged internally or other circulation problems

That has all been checked out.

 

[OzDozer]

RC, you need to soak those radiator tanks in an acid bath to clean up that corrosion.