I have a 1987 D4H dozer that I believe the radiator core or cores need replaced. The dozer doesn’t run hot according to the temperature gauge, but the gauge we show all the way hot for a second then bounce to around 190. It bounces back and forth, which maybe a faulty sensor. The main issue is the trans fluid warms quickly and after 1 Hour the transmission will not engage in gear. Ive pressure washed the radiator and tightened the belt. It will blow your hat off at high engine idle, but I believe the internal cores maybe clogged. Can a radiator shop rebuild cores? Or is there a flush system to clean out the cores? I saw I brand new radiator and assembly for over $10k, but the Individual cores weren’t but a few hundred a piece.
Can you start with a Serial Number please so we can look at parts.? Also the first thing I would suggest is to get a hand-held temp gun and start shooting some temps, especially the radiator inlet and outlet hoses. Your temp gauge fluctuations may be wiring-related but again need to look at the details of the specific machine.
SN:8PB01009
Attached the parts breakdown of the radiator. It is a folded-core type containing 4 cores plus the oil cooler. As mentioned above IMHO you really need to be getting some temperature readings before you even think about buying parts.
ı would help you to find radiator cores.
He doesn’t need radiator cores until it is proved that they are the problem. Right now it is probably more likely to be an electrical issue.
Thanks Nige. I did a complete service on the dozer a couple of years ago and once we got it running this is when the issue started. I’m wondering if there maybe be an obstruction in the transmission lines to the cooler causing the roughly 1 hour run time before the gear will not engage. I honestly don’t think I clean any screen out with I changed the transmission oil. It seems I remember draining the oil and changing the filter under the floor board. I remember a couple of screens on the fuel side. Of course, this was two years ago. The dozer may have only been ran a couple of hours since the service. Where is the screen located for the transmission oil? I have a service manual, but I’m out of town.
See attached Item #34. Removal & cleaning ought to be covered in your O&M Manual under changing the transmission oil. I assume that you have one if you have a Service Manual. TBH first get some temp readings from your upper & lower radiator hoses and let's see what they say.
Got the thermometer on order. Hopefully will run some temperature checks this weekend. Thanks again.
One question on the screen removal. How much oil will I lose when I check the screen? I have about 4 gallons of the CAT trans fluid left.
You'll need to drain all the oil from the transmission otherwise you'll be wearing it when you pull the screen out. That's why the process of cleaning the suction screen is considered to be part of a transmission oil & filter change.
Was hoping since the screen is up high that the oil wouldn’t all drain out. I would expect some lose of oil, but not the whole 30 something gallons.
The oil level in the transmission has to be significantly higher than the screen otherwise all the pump would suck would be air. I think the drawing gives a false impression, the screen is actually quite low down in the case. If you take care you could drain the oil into a clean container and reuse it provided that it is in good condition. Check the colour, it should be clear and bright and not have a burned smell.
Just went through this on our D4H, 8pb06217, at 8k hours. It moved well cold, but began to travel slower and slower as the machine warmed up. The decel pedal was binding. The needle bearings were rusted and missing needles on the cross shaft. Fluid and screen were spotless and not the cause.
This thread HeavyEquipmentForums shows the screen setup on mine.
I would assume if the decelerator pedal was your cause, wouldn’t you notice the engine rpm’s dropping? Our main throttle lever will stick wide open but I just use the decerator pedal for rpm control and for gear changing. Now when I get ready to Turn the engine off I have to jump on the tracks and reach my hand in to the level and manually push the govener closed to turn the dozer off. There is no side engine panels as they were stolen years ago. I’m kinda at a crossroads. I’ll wait for the temperature gun first to check temps, then pull the screen. I should have enough 5 gallon buckets to catch most of the oil. I spent a ton of money on the CAT brand transmission oil and don’t want to re spend that again.
Why not check it and eliminate it as a possible cause.? You have nothing to lose at this point. It shouldn't be too hard to check.
Maybe I'm mistaken on the pedal description...one of the pedals was not returning fully. Mine had the same symptoms, slower as it warmed, to the point that it wouldn't climb a grade at all. IIRC, pulling up on each pedal would help.
Just found my dozer. It was the service brake pedal.
I was able to run the dozer today and checked temps with an infrared thermometer. Everything is in degree Fahrenheit. The line on the water pump that looks to have the temperature sensors showed 190 after the engine had been off for about 5 minutes. The lower radiator hose on the other side of the dozer was 160. I took several other temps. The cylinder head was 220 with the turbo over 500. The power trans temp got to about 175 on the gauge. I walked the dozer about a mile with a couple of steep hills. The water temperature gauge went to about 140, then went all the way to right and maxed out. Did this for about 1/2 the time. I did notice when I went down hills and lowered the throttle, the temp gauge bounced from 160 to max. My question, is which sensor is the temperature sensor so I can replace? Anyone have a diagram?
The possibility of air in the cooling system.? A gauge bouncing around like that could be a temp sensor, it could also be a wiring issue. Here's a view from the left side of the engine. The coolant temperature sender is #20, it screws in from the left side. Part Number is 6N-5926. Be careful because there is also a temperature switch #4 there. Don't get the two mixed up.
Thanks Nige. That is exactly what I needed.
Well. Never ending. I bought a thermostat as well to replace since I don’t know when the last time it was replaced. Both thermostat housing bolts broke right off at the head. The sending unit was supposed to be delivered Friday but won’t be in until Monday. I guess in the meantime I can somehow pull the broken bolts out. Anyone know the size of the thermostat housing bolts?
5/16-18x1.125 along with a flat washer...times 2.
Wonder if a hardware store or auto parts store might have them.
Got the bolts. Tested the thermostat in boiling water and it opened just fine. Had to pick up an extractor tool to get the thermostat housing bolts off. Hopefully I can reassemble and check the temps again. The new sending unit has been installed as well. Maybe I’ll get everything going this evening.
Welp. No luck with heat and cold water. Broke the stud even. I ended up just vice gripping the other side since I was able to get the bolt out of the other. I ran the dozer for about 15 minutes back and forth and the temperature gauge did not move. Used an infrared thermometer and temps were 180 at the housing. What I’m going to do is sandpaper the old sending unit to a clean copper finish and reinstall. If that works then I’m done. If that doesn’t, then I’m just going to get a thermostat from an auto parts place and hook it up. Probably should have done that in the first place.
Unless the temperature regulator that’s in there now is marked with a setting telling you at what temperature it’s supposed to open then I would suggest that you’d be better buying a genuine Cat one that will be guaranteed to open at the correct temperature.
The temperature regulator is Part Number 4P-6616, the gasket under the regulator housing is 110-5236.
I think the OP doesn't mean thermostat in his last post...I think he means temperature gauge?
It’s the temperature gauge that is not reading correctly. I replaced the temperature sending unit. I ran the dozer for 15 minutes and the temperature gauge did not move. I used an infrared thermometer and shot the temperature at the sending unit and it was over 180 degrees, but the temperature gauge read 0. I also removed the thermostat to confirm if the thermostat was opening at 180 degrees with a pot of boiling water and it opened just fine. Reinstalled the thermostat with new gasket, minus a broken thermostat bolt (now clamped with vice grips). Everything seems to run fine but the temperature gauge still does not work properly. I sanded down the original cat sending unit since the copper probe was black which maybe was causing incorrect signals to the gauge. I’ll put the old one back on and see what happens. If that doesn’t work, then I’ll just run my own thermostat gauge.
Temperature gauge installed. Didn’t get over 200. Stayed around 190. Ran the dozer for a couple of hours with 100 degree heat. I still had to stop and let the transmission cool down. It would not go in gear after it gets to 220 degrees.