Now that we have the steering clutch issue successfully repaired on our D6C, I want to improve the situation with the trans running hot after prolonged use, that I mentioned last year, so think the first thing to focus on is the cooler up by the water rad. It has a lot of bent fins & looks somewhat plugged as well & but they are hard to get at to straighten, so we plan to pull the cooler out, clean things the best we can, straighten the fins etc.. We have a good local rad shop who may be able to do a re-core on it they said if need be, without actually looking at it. It is over $1,700 for a new genuine Cat cooler (3 days away), but want to avoid that option if possible. Has anyone had success with boiling out the cooler cores somehow, or pressure washing them? We tried to reach in & straighten the fins one at a time, but a nasty job & slow, so taking it right out is our best option. It has no leaks, just bent fins & dirty from what we can see. There could be issues with he torque converter from what I heard before, but thought it may be best to start here. .
It's hard to tell from the photo on the right if it is simply fins that are bent or if the core is actually plugged inside with something like dried mud. Maybe a radiator fin comb would have the desired results on the fins which would then let you get a pressure washer at whatever might be blocking the air flow through the core. I would plan on getting the cooler out and post some more photos, especially one where you try to look through the core preferably after you have attempted to straighten the fins.
Sure....can do that.
If I remember right, my D6c has a steel oil cooler rather than brass/copper like the engine radiator.
Any advice as how to jiggle the oil cooler out of there?......we can't get it so far, need another inch of space to get it out. Does the water rad have to be removed first?:crying
Hey metal man just a quick observation but from that pic the oil sure looks Burt when you opened lines did the smell grab your nose. I'm no help on getting cooler out some other manufactures nose cone would come off and allow access just a thought
They should both come out together and separate then. Later Bob
I'm not too up on Cat dozers, only worked on half a dozen or so over the last 45 years, but the heading of this thread says D6C-Transmission Cooler. Unless I'm looking at the wrong serial number prefix the cooler shown in the pictures is for the hydraulic system in the pages I'm seeing. The transmission cooler, at least the Power Shift model I looked at on SIS shows the cooler to be a water to oil cooler on the engine. Like I said I'm far from an expert on D6C's but that is just how the 966C's of about the same vintage I have worked on many of were built. I did do a little more looking and seems there was a change from one style cooler to another but could not see anything that said where the change was implemented. Also dug back it the forum to see the early picture of this Dozer and in the picture I can see there is no cooler other than the engine oil cooler on the left side of engine. But that being said it does look like the radiator does have to come out.
yes both come out as one, then separate. At the inlet to the air to oil cooler is a thermostat bypass valve, that opens after a certain temp to let oil through the cooler; check this first. as if it does,nt open will be no flow through the air to oil cooler ! re the injectors, you can just fit new or reman ones. Injectors don,t control the amount of fuel injected, that's controlled by the pumping elements and rack. Injectors only control the spray pattern and most importantly Valve Opening Pressure; which for 7N0449 injectors is 2400-2600 psi
If I understand it correctly, the valve at the bottom on this one is for pressure bypass only. If the rad plugs & will bypass. I think that some of the later models had the temp controlled flow valve? Do I have this right? We had originally thought that this bottom valve was for a temp operated flow control too, but not now. So both rads come out the top then?
Right, ours has no water/oil trans cooler on the side of the engine.
Merv, I re read your post & see that you are saying there may be an air to oil cooler on ours, with a thermostat inside.......did not see that but will look again. Can you explain its location? I don't believe that to be the problem however as the upper & lower cooler tanks do get hot, which means there must be flow??
It should have trans oil to water cooler at 90 degree rear vertical position to the horizontal engine oil cooler As well as the oil to air trans cooler alongside the radiator. My early D6D has this setup; but my later D just has a larger oil to water trans cooler and a full width radiator. However both mine are Japanese 31X series. possibly the American 4X had a different setup. A parts book for your serial # should confirm it. yes valve im talking about is a cooler bypass valve. it is designed to start closing at 57c and be fully closed by 77c. oil actually goes through the oil to water cooler then to thermostat then oil to air cooler. oil pressure after it comes out of the TC outlet relief and enters the coolers is controlled by the lubrication relief valve. Later D6Ds had a different valve to raise the lube pressure to 20 psi over the earlier 10 psi
sorry metalman I thought you had a D not a C. Anyhow yes late Cs should have the 2 oil coolers,, same setup as early Ds. disregard what I said about the injectors, that's for direct injection 3306. the C only has precombustion chamber nozzles that squirt at 750 psi. just replace them with new ones as they cannot be serviced. they are either good or no good. Appologys for my misreading of your post, must have got it confused with the post below it about a 4x D6D cheers :drinkup
Don't know your serial no. or engine arrangement no., but this is what my 10k looks like. Like D6Merv said, I'd make sure the thermostat valve on the air cooler is working. Otherwise cleaning and straightening the fins is about all you can do to the cooler. With it being an oil cooler it shouldn't have internal problems like water radiators do. Are you sure it doesn't have a trans cooler on the side of the engine too? Both Air/oil & Oil/Oil coolers are hooked in the same circuit on mine and depending on oil temp the thermostat regulates flow to the air cooler. Second scan is of oil/oil cooler that's normally on the left side of the engine. Mine is the 4N7365 arrangement. View attachment Cat0001.pdf View attachment Cat0002.pdf
Something strange about this engine arrangement. It appears to have only the air cooled unit and no engine air to oil unit. Does not appear to be the standard dozer arrangement but the Service Manual does make reference to the 980 arranged this way. Look back at previous post on steering clutches for picture of the engine.
Look at the second pic (LH side of engine) there is no Torque cooler, just the Engine oil cooler. I don't know about the D6 but the 977's and 955's with oil to air coolers have bypass valves, 977 is simple washer and spring but the 955 is a more complicated pressure and temp sensitive unit. They are part way down the lines and can be checked by feeling the lines for heat. Later Bob
Sorry, meant to say water to oil cooler (torque cooler). To late to edit that post now.
I took another pic of the LH side of engine today, only an engine oil cooler there I believe, no water/oil cooler. We took both rads out this morning. Sent pics to the industrial rad shop & they are scared to touch the oil cooler, fearing the pressure, so we are going to straighten all fins best we can, power wash the outside & flush the inside of the oil cooler & reassemble. We will straighten some fins on the water rad while we are at it & power wash through it as well, even though we have no problems with the coolant running hot. It looks a little rough as well, but we will take our chances with it. Someone earlier today wanted verification on our Ser # & it is 10K6516 & could not find an arrangement #.
call b&b enterprises, 800 255 7968, they make supplemental coolers for situations like this and might be able to help you.
Arrangement no should be on engine tag (left side, towards rear at base of cylinders) or can be found on tag on dash by brake pedal. My parts book starts at s/n 10K7953 so doesn't cover your machine. Looked up your s/n on Cat's online parts and it doesn't seem to show the oil/oil cooler either so apparently they were added later. Suppose it would be possible to add the cooler but would require quite a few other parts....hoses, cooler elbow etc. If checking thermostat, cleaning it up, and straightening fins doesn't help it would make me wonder if something in torque converter or trans is generating too much heat. (It does look like you've got a lot of flat fins on the back side of the cooler)
If you think you'd like to replace the oil cooler, I would think you wouldn't have too much trouble find a good used one.
Got a chance to dig a little deeper. Apparently the early 10K's went from jacket cooled torque converter oil cooler to air cooled at s/n 10K5205 to s/n 10K7062 then back to jacket cooled. Lines do not have a temp control valve and use the 1P9799 by-pass valve group. This is all on the D333c engine before the change to the 3306 at s/n 10K7953.
That machine has the D333C engine in it. Later Bob
My 69J D6C only had the air cooler I got a cooler I think from a TS14 mounted it across the front joined the two together an it work good.No one really knew why it never had the water cooler as ones before & after had had them.It was the 3306 140 hp engine.Cheers
Probably from the same s/n era as the 69J is the Japanese equivalent of the 10K.
We straightened all the fins on the oil cooler & then power washed through the fins.....it came out real good, able to see daylight right through & we were impressed with the results. It was not leaking at all before, so we are hopeful that it will work more efficiently. We had no problems with the water coolant rad, but are doing the same with it as well while it is out.
That actually looks quite tidy now ....... how much (if any) dirt did you find packed into the guts of the cooler behind those bent fins..?
There was a fair little bit trapped in behind those bent fins. Got it nice & clean now. We did a rinse inside of the cooler as well with mineral spirits & it was not too bad inside. Took the tanks off the coolant rad, cleaned them out & have some blocked tubes to clean while we are at it. We will try to flush the tubes once cleaned as well. Ordered new gaskets for the upper & lower coolant tank. Plan to make a new rubber closure piece for the bottom of rad to ensure the best air flow & stop the air from recirculating under the bottom of the rad.
You can use the fuel tank dipstick to rod out the rad tubes then blow them out with air. That will help with engine temp. If you got much out of the TQ core that will help cool the trans. Later Bob
Now that sounds like a good idea, as the shape is similar. We were talking about just using a piece of round wire, but that would be a bit tedious.
I've never seen a d6 like that over in the UK. Looks like you've done a good job cleaning every thing up.That will definitely run cooler now.You can't beat getting the rad out to give it a proper clean up occasionally.
This tractor had been suffering a weeping crank seal for a year.I had to power wash it out every week through the summer until we had time to repair it properly. It wasn't getting hot or anything , but it was starting to develope, so we headed down with new seal and seal path,cooler gasket kits,new belts and power washer.Now is a good time to replace all pulleys and belts as they aren't that expensive and you would be suprising what a difference it makes
I was out on a d8 this week myself to set it up for a job and you can hear the fan a mile away
Looks like a nice well cared for machine nicky. Is that an H or K model? If I remember correctly, when they came out with the K model, they increased the fan speed over what the H was, which would account for more noise coming from the fan.
Well, we finished cleaning up the coolant rad, unplugged perhaps 20 plugged tubes in the core with the fuel dip stick (a good fit) as was suggested, cleaned the inside of the tanks, power washed through the fins on the outside, put all new tank gaskets on & put it back in together & guess what....... it leaked. Took it out again & sent it out for a re core (looks like a nice re core job so far) & now it is back in once again. Just finishing the install of the remaining guards etc. today & will fire it up it up to try it out.
All back together & no leaks this time!
That will happen sometimes, the gunk you cleaned out was sealing up the rotted core. At least the second time coming out everything was clean and bolts come out easier! NIce to see people who take care of this older equipment, saw too many abused where I worked. If they could run till lunch time before topping off oil and coolant some bosses felt that was good enough! Then there were the ones who felt that as long as oil was coming out the dirt could not get in!