I have an old snow blower truck that has a great running 6v92t for the blower. I was hoping someone could give me some clues about the most likely places the coolant could be leaking into the oil. I don't see any oil in the radiator and I pulled the inspection covers off the air boxes in the block and don't see any evidence of coolant there. Any advice I can get is greatly appreciated. Please excuse any lack of knowledge I might have, since I am not a professional mechanic. Thanks in advance!!
Check to make sure that the weep hole for the water pump is not plugged.
How much coolant over how much running time? Most cases are liner orings or head orings.
Dang mud daubers can be a bitch about plugging up those hole especially on an engine that sets for long periods of time! Had a 16V-71 water pump seal that would not leak coolant under pressure but would when set over night. So if checking do it both ways. Almost forgot to mention, INJECTOR TUBE ORINGS! Pull valve covers and look for trails coming down from under injectors. Might also be able to see leaking from head seals if looking down the oil drain hole at lower edge of heads.
Thanks for your responses. I don't have a very good guess as to how much, but I do know it has extremely little run time on it. I bought it a couple of years ago and it had fresh oil changes then. The only run time is an occasional start just to get the batteries charged and get some oil circulated. I wanted to use it over the last month with the heavy snows. I checked the oil and thought it looked suspicious, since it was just starting to get a milky look to it. I cracked the drain plug and got coolant running out to make sure. A heavy equipment fella I know told me to check and see if I had oil in the radiator. I think I put about 4 gallons of coolant in to get it up to where I could see it in the radiator.
You might want to get an ultraviolet setup with dye, special glasses and a special flashlight. Add some dye to the coolant, then run until it's circulated, then remove the valve covers and pressurize while shining the dye light around and down the oil drain holes. Or you might get lucky like I did, just remove the valve covers and you happen to notice a small trail of coolant. A drop of water stands out from the oil in there by sight a little bit.
Please correct me if I am wrong, but the repair manual I bought shows a wet sleeve on top of the air boxes and a dry sleeve below? Therefore, I'm assuming that if is liner O-rings it would leak into the air boxes and not necessarily into the oil pan? Thanks for everyone's help!!
The engine does have a supposed history of sitting for long periods. Supposedly, a fella bought it back in the 80's and fixed it up with a new blower engine with the idea of getting a big snow removal contract. Evidently, he didn't get the contract and it just sat for many years. Another fella bought it from him and it mostly sat for a few more years. I've had it for a couple of years and ,obviously, has pretty much sat most of the time here. Like I said earlier, I'm not a professional mechanic, so I'm not really sure what I'm looking for in a water pump weep hole in a detroit, but hopefully can figure it out. Thanks again for everyone's help!! This forum is a great opportunity for me to learn from everyone!!
Well to be honest here I have had almost no experience in the 92 series my self! First off you are probably right that if the coolant leak was from the upper cylinder orings the coolant would go into the air box and not straight into the oil pan. Also there are drain lines from the air box that "should" let to coolant drain out or at the least most of it before it has a chance to get to the oil pan. I say "should" because those pesky mud daubers mentioned above could have plugged up those drain pipes as the engine sat for long period of time. And the oil rings at the bottom of the pistons "should" hold the water from getting to the oil pan, but they are not without ring gaps and not knowing how long this coolant leak has been going on there might have been time for it to drip through over time. One more thought or two. Are you sure it is coolant in the oil and not just water from condensation over the years? Also are you sure the radiator was ever full?
If you run out of suspects, sometimes oil coolers go bad. They corrode and start to leak. This is especially true if there is a history of using untreated tap water as coolant.
The earlier 92s had air box drains back to the pan, most were bypassed back to nature as all good Driptroits were, check to make certain those tubes are not connected to the oil reservoir.
Thanks Again for everyone's help!! I'm pretty certain that the water in the pan is not just condensation, since it was green when I loosened the drain plug. I'm pretty certain the drain to the air boxes just go to the outside, but I will double check. I don't see a weep hole in the water pump, but I do see in the manual where it shows a water seal that supposedly can be removed without taking the pump off. I can't say for certain that the radiator was full. Before I took it home I had a fella look everything over to make sure everything was up to par, so I don't recall if I checked it or not. I would think that I would have, since I'm quite a stickler for stuff like that.
My heavy equipment friend thought that if the oil cooler was the culprit that a person should see oil in the radiator, since the oil pressure would push it out? Does this sound right?
With the engine running usually get oil to water if a big enough leak will flow both ways. I too would fall back to w/p first, there is a intercooler in the engine valley below the blower, if the drains do go back to the block and oil pan that is another likely spot.
I'm just assuming the water pump on a 6V92 is more or less the same as on 8V71 so I would be very sure there would be a weep hole. The thing is you may not be able to see it with pump mounted on the engine. I dug out my 1981 92 service manual and for some reason they don't see the need to show the weep hole between the coolant and oil seals. I would be very surprised if there was none! They do say the seal "can" be replaced without pulling the pump but it would not be my plan of attack if it was my engine. I'm thinking this because if the coolant seal is what is leaking and the coolant is getting into the oil it has to be bypassing the oil seal so that seal maybe damaged as well.
Could be just Maybe injector coppers, and I said Maybe. Not seen much I have only witnessed one leak coolant to the head surface but can happen.
I've seen coppers leak. Pull the valve covers and check any soft plugs or deprecians on the top of the heads. The coolant will accumulate there and engine oil will cover it up. A quick dip of your finger will displace the oil and any coolant will show up green. A leak on a copper will drain back to the pan with the oil.
If I would pull the water pump cover off and pull the impeller I'm assuming the weep hole would be behind the impeller???? Thanks again for all the great responses!!
Your best bet would be to drain the engine oil, top off your radiator, and pressurize your cooling system. It would be ideal to have the oil pan off the engine so you can see where the coolant is coming from. At least it would help you narrow down a specific area of concern. You are correct in that the upper liner area is wet sleeved (meaning antifreeze makes direct contact with the liner) and the lower part of the liner is dry sleeved. Leaks at the liner orings generally have antifreeze in the air box which is normally drained through the air box tubes to the ground providing they are not plugged up. Leaks at the injector tubes on the tip side usually end up in the airbox also depending on the position of the piston in the liner. I have found more times than not that these leaks accumulate antifreeze to create a hydraulic lock when trying to start the engine which ends up in a bent connecting rod. There is orings under the top side of the injector tube outer flange that can leak also.....you would see this with the valve cover removed and the cooling system pressurized, in which the antifreeze would go straight to the oil pan. Leaking head orings usually go straight to the oil pan. An intercooler under the blower can leak antifreeze but that also usually ends up in said airbox. If you have found no antifreeze in the airbox at all, then I would first suspect the water pump itself. They can leak water from the driver shaft side straight into the oil pan. JMHO of course.
If it is possible to get the pan off that would be an excellent idea. I would be tempted to start by pulling the valve covers and look in there. Next maybe remove at least one airbox cover on each side to see if there is any signs of coolant there, coolant runs down hill so if one end of engine is lower than the other remove cover from lower end. And if you have not already started the engine I would not try that until you are sure where the coolant is coming from and going to, bent rods are not a good thing! If you must start I would suggest turning over a couple turns by hand to besure you do not have a hydrostatic lock condition.
Thanks again for all the terrific advice!! I don't need to start it, since 6v92 just runs the blower. The truck is driven by a smoking 471. Pan can certainly be pulled with some "remodeling." If I don't update you all right away it's because my day job is a rancher and we are going to be calving soon. I really appreciate everyone's generous advice and help!!
So looks like you maybe using one of these for a while: https://www.ebay.com/bhp/calf-puller
We only ever had chains and come alongs.
Emeryville con queen cab. Mid sixtyish? The w/p is a whole lot easier to rebuild OFF the engine.
My thoughts too. And looking at the upper hose on that pump I'm thinking replacing the hoses to the pump would also be good insurance no matter what! But let's not forget we still need to find the source of the leak and not just start shooting at the hip replacing things! Would sure suck to pull that pump and rebuild it and put it back on and find out the leak is a bad o'ring on the top of an injector tube and have to tear the engine back apart again.
Pull the valve covers before you do anything else.Ive had three detroits that had injector tubes leak. Easy to see the problem, not an easy fix. The weep holes on the back side of the pump, hard to see but my thought is that's not he problem. I've never had a water pump seal leak to oil. I have had them seize up and break shafts and lose the impeller and leak out the weep hole but never lose both seals. Good luck keep us posted!
We hope to not use a calf puller too much. I haven't used it at all for at least a couple of years. The cab on the truck is an international. I think the running gear is supposed to be a fwd. Supposedly, a fella from North Dakota bought it out in Idaho and when he fixed it up did a cab swap. I hope I can get time to pull the valve covers before the calves start coming fast. Thanks so much for all the terrific advice!!
Won't say it is common but did have a coolant in oil problem on a 16V-71 that I spent most of a day watching with air pressure in radiator trying to find source of leak. Four valve covers off watching 16 injector tubes, looking down oil drain holes in four heads dropping oil pans, yea two sumps on that engine, not a drop seen anywhere. Nothing out of air box drains that were checked to be open. Left for the night and came back in morning to see a trail of coolant across the shop floor. Followed it back to truck and see it coming down from front right side of engine. Shine flashlight up inside and drips coming down the inside of the front cover right below the water pump. No other water near that point so knew it had to be the pump. Removed the pump and find the weep hole plugged solid with mud dauber crap! For some reason the pressure on the coolant had actually helped the water seal block the coolant but when pressure was off it leaked!
The 16v-71's look like really sweet engines!! I wish I had an excuse to get one! LOL!
I have had much the same findings as Kshansen. When I was a younger man, everything we had was detroit powered. While it was not a common failure, it did happen so it was one of the first things we looked for when we found coolant in the oil.
And not just with Detroits, recall at least a couple 3306 Cats that had the same problem. I would say any gear driven water pump is susceptible to those dang bugs sealing up weep holes. Just wish the designers took that into account and put the weeps in an easy to see and clean out position! Now that I'm thinking, second cup of coffee kicking in, recall I believe it was Cat that came up with the idea to put a little foam filter in some weeps holes. Another brilliant idea that probably looked great on paper! Who would have guess water and dust would seal off the pores in that foam plug?
Kind of like the old compressed bronze fiber fuel and hydraulic tank vents that would seal off from goo accumulation!
Yea. they have a JD back-hoe at the quarry and a couple times a year I would be told there was a problem with it, no power hardly able to climb hill out of the pit. Remove fuel cap and flush out that bronze vent and runs like new engine!
Finally found the w/p weep hole. LOL. Don't think it was plugged, but did try to clean it some just to make sure. I'm assuming the weep hole lets any coolant drain that gets by the water seal in the pump to protect the engine??? Therefore, if it's not plugged there's approximately a 98% chance the coolant in the oil is not coming from the water pump??? Is this correct??? Hopefully, I can get the valve covers pulled before too long. Good thing I bought a radiator pressure set at an auction a couple of years ago. Thanks for your help!!
That's a wicked looking machine.