I have a D6C LGP ser.#90 B1849 engine#44V8821 We just rebuilt this whole engine and replaced almost all the internal parts: new liners, pistons, camshaft, crank, cylinder head… The block was all striped and cleaned with a hot pressure washer, everything was clean before assembling. Before putting it back in the machine we test run it without the radiator, just on flowing cold water. Everything seemed to be ok, temp. was ok, did some fine adjustment on the governor and put it back in the machine. Before turning it on I checked my temperature gauge and I discovered that it was faulty: in boiling hot water it would still be half way in the green. So I got me a new temperature gauge with a Fahrenheit scale on it. When I turned on the engine I was warming it up for 5 min. and then start driving it. After just another 5 min. without even putting a load on it my temperature had reach already over 200ºF . So I stopped. I suspected the thermostat was bad; took it out and run the machine without it. First when I warmed it up for the 10 min the temp. stayed below 100º, then when I started driving it again the same thing; after 5 min it was over 200º. I also checked the thermostat in hot water; it starts to open at 185º and is fully open at 195º. So I double checked the new temperature gauge but it was ok. My friend said to check the oil cooler, which also was cleaned before assembling, took it of and it is ok, nothing plugged. Next was the radiator, took it apart and it looks good; I had 1 or 2 of the cores plugged, all the other ones look clean and no restriction in flow. Now I am at the last stage, the water pump; took it apart and pulled the impeller. To me it looks pretty ok, it’s not a new pump, so of course some wear. The space between the impeller fins and the housing is a bout 1/8”. Does anybody think that pump could be bad? Has anybody an idea what else could be wrong? We are pretty much at the end of our troubleshooting??? But I am very certain now that this overheating and the bad temperature gauge caused the engine failure in first place, so we have to fix this. Any Help thanks a lot.
Can't help you with the water pump but, is this a powershift machine?....If so how's the torque converter temp? Could it be the torque converter is flooding and generating a lot of heat? Which oil cooler did you check?...there are 3... engine oil, and trans coolers on left side of engine and the trans cooler next to the radiator.
Is your replacement temp gauge a genuine Cat item or a "will fit"..?
Before you tore it apart did you check for water circulation?
What does the outside of the radiator look like? fan? fan shroud? Use a non contact thermometer to check the temperature of a painted surface on the top and bottom of the radiator, I'll guess you don't have enough difference because there's not enough air moving over it. Or, the original gauge was fine and 200 isn't too hot in Cat's mind.
No this is a direct drive. I checked the engine oil cooler, tomorrow I will also check the trans oil cooler, just to be sure, but I don't expect anything in there as we also cleaned this part before assembly.
No it's not genuine. I bought a cheap one. But as a I said, I verified it is working properly with a good digital one on different temperatures.
We did check for the circulation and there is. I can't tell if it's enough, my friend said he thinks it should be more and that something must be restricting the flow. Just can't figure out what and where.
Well, you know this thing is not new, so there is some rust here and there; the radiator looks ok, the cooling fins are intact, no restrictions for the air flow. Fan looks ok, blades are not bent or chipped. Shrouds are in place. I will check the surface temp tomorrow. You think 200º could be not to hot for that machine This thing is built in the 70's and as far as my understanding goes diesels weren't engineered to run that hot, but i could be wrong. I think it should be between 180 to 190, nothing more.
Synptons sound like impeller slipping on shaft when it warms up. Friend of mine had d6d do the same thing,new pump fixed. Bill.
Does the radiator fan have reversible blades ? If it does be sure they are all locked in the same position. An unlocked blade will tun itself to a flat position and cause what you are describing,
Restricted flow! I once put a new radiator in and had to make a gasket for the bottom water neck, perfect cut, four neat holes put it together and I had your problem, I forgot the big hole in the gasket. Oops
I s'pose fuel pump phasing is OK? I have known motors to run hot with next to no load when phasing is out for some reason or other. Cheers, Greg
I doubt the impeller is slipping. I had quiet a hard time pulling it of the shaft, it was stuck on pretty good.
This i cannot tell. The engine is a little hard to start but she revs up good. But my friend said that the fuel pump might need some calibration done sooner or later. So I don't think I can do much on this side, or??? Probably only could send it in the shop for servicing.
Yeah that is what I am wishing to find today. I know my friend made some of the gaskets himself, also the bottom one in the trans cooler. Will take it off today and check. Wish me luck
Did you use genuine Cat gaskets or aftermarket? Could be that if aftermarket parts were used, a gasket may not have been cut right and is blocking a water port. Do you remember if there might have been a chance that something got dropped into an open area of the engine when it was apart? I am starting to reach, but you seemed to have covered most of the basic stuff.
The impeller blades looks like they've been riding on the water pump housing face. There should be at least a small gap there. Is it possible that the shaft is loose in the drive pulley or bearings or missing spacer/thrust washers so as to allow it to ride on the pump housing? How tall are the blades supposed to be? If they are worn down from rubbing the housing the gap will be too wide which will cut way down on the pump efficiency. PS: Is 200 degrees abnormally hot for the water outlet temp on an engine that is working? I'd expect to see outlet temperature near 240 or more on a loaded engine.
I'll just throw this out there since is has happened before.When you drain the block and everything.Like if you was doing a complete flush of the block ,when you fill it back up with water you will sometimes get air locked in the head.When you start it up it will start heating up right away.The exhaust will not look normal also. Usually you have to take the temp sending unit loose on the head to get the air trapped out of the machine.Sometimes if you run it long enough it will wokrs it's way out and other times you have to loosing the sending unit.Good luck
We used aftermarket and what was missing we bought from CAT or made it ourselves. We checked pretty good to make sure everything fits and is ok. I also dont think we dropped anything inside the engine, we took a while to build this engine back together.
I noticed the marks too was wondering how it could be that the impeller was scoring the housing. Under the impeller is a spring which pushed it away from the housing, so there is a space of about 1/8" from the impeller blades to the housing. I don't know the how tall the blades are supposed to be. Today i noticed that I can move the shaft back and forth a little bit, maybe 1/16", but maybe that's normal too? For the temperature: I am not sure what it really should look like; my friend has the same kind of machine and says his is running between 180º-190º and it should not be hotter. We just had an engine failure and that's why i am so afraid about overheating it. I called CAT today to find out was is the operating temperature for this machine, but they didn't got back to me. So will call them again on Monday.
That's a good one; indeed it could be that air is trapped. I will check on this tomorrow and see if I find something. Thanks
How did you pull the impeller off the shaft? Was the bolt that holds the impeller on tight?
The scratch marks are rough machining, it's not an injection pump. If it was rubbing it wouldn't be even across the impeller. The spring is usually part of the seal, it shouldn't hold any pressure on the shaft or impeller. Hopefully somebody else knows if there should be any play in the shaft, I can't say. 180-190 is nice but 200 is no concern for a working machine. Now if you start it and it goes to 200, then 220, then 240 that's when you need to be real careful. If you run it a bit and it's at 200 and stays there as you work it, that's no problem as long as there is circulation so you're getting an accurate temperature. The temperatures going out to the radiator and coming back when it's hottest might narrow things down.
I had trouble with my 6c running hot....checked about everything I could think of. Rad core had small leak at bottom and the rad shop didn't think it would hold for long if they rodded it out and soldered it. (Rodding out can create more leaks if the tubes are thin) I replaced the core and no more heating problem. It didn't look all that bad when I took it out but it must have had enough crud in it to restrict flow & heat exchange. Kind of an expensive fix if you're not sure that's the problem but if you end up replacing it I got very good service from RoCore. They build to order and I had it it 2-3 days....although shipping to HI may be prohibitive.
The bolt was tight. Loosened it about 1/4" ant hit with it with a rubber mallet. Didn't come right away, only after additional help of a small pry bar.
If your getting to 200 in ten minutes I would really expect a water flow problem, was radiator also 200, top and bottom or just engine? Fuel timing can cause heat pushing, I don't think idling. Need to see if rad is getting hot,
Was the fuel system rebuilt when doing the overhaul? Also maybe recheck the pump timing, too far out of time will cause hard starting and heat. Slobbering nozzles will also. Just a couple things I was thinking you might check. Good luck.
No we didnt rebuild the fuel system. Though I think it would maybe be good to do. She is a little hard on starting, at least a little more than before the engine rebuilt. I have to glow it longer now. So probably signs for time to overhaul also the fuel system.
And that's what happened today: I put everything back together, a friend also told me he would drill a small hole (1/8") on top of the thermostat, so that the air can escape, so I followed his advice. While she was warming up i also loosened the temp sending unit to let eventual air escape. After warming up I run her and the temp was keeping steady no overheating. I worked her for 15-20 min and she got up to 195º-197º which I believe is acceptable. So all this trouble seemed only because of some trapped air :Banghead Well at last...solved this problem. Thanks for everybody's help. Though she's not purring yet, there is some knocking going on in one of the cylinders, specially as she got hot it was really bad, which might bring me back to the injector pump. Will investigate tomorrow.
Be sure your cooling system is holding pressure, too.
Unless everybody knows something I don't :beatsme , then I'd suspect the injectors dribbling before the injector pump. Cheaper and easier first. Disconnect the lines one at a time and see if the knocking goes away.
Yeap, pressure seems to be holding, didn't check with a gauge, just open the filler cap when she was hot and there was my pressure.
You're right an the injection system. Opened all the lines and the knocking went away when I opened #1 Will try to get a new injector tomorrow from our CAT dealer. Hope it's just that.
Replaced that one injector and voila...the knocking was gone, at least for the #1 cylinder. When I reved her up she sounded ok, but as soon as I put a load on her there was some more knocking. Also didn't seem to bring up all the power she's suppose to do. So decided to change all the injectors. Gonna order them tomorrow.