Bought a M929A2 today, I changed the oil before starting & found 2 Quarts of anti-freeze; assume blown Head Gasket?

[levitate]

Today I went to pick up my 1991 M929A2 Dump Truck which I've just purchased; estate sale situation.
The seller had been holding it for another buyer, they ended up backing out because of potential water in the oil.

Solid M929A2's dump trucks don't come up to often in Washington State so I jumped on the deal which came with a M116A3 trailer and MEP-802A 5KW generator.
Knowing water might be in the oil, as a matter of course I installed all new filters and started to change the oil.

When I drained the oil there wasn't just water from condensation due to sitting for six months as I had hoped for; the oil was mixed with three quarts of antifreeze..
Luckily it's not been started by myself or any other buyer in this situation; the last time it was even warmed up was at least six months ago.


I left the truck at the sellers place and I need to go back in the morning to work on it; I'm looking for advice.

1. Must I assume this is a blow head gasket and tow it?
2. What's involved with replacing a head gasket on the Cummins 6CTA8.3?
3. Would it be reasonable to perform a flush with new (cheap) oil and then fill with decent oil to see if it blows white smoke or has temp issues before towing?
4. I've been told by radiator repairmen never to use the copper additive antifreeze fix; is this a option tied with #2 above or will it damage a sensitive sensor or something else?

This is my first post so don't beat me up too bad.. I appreciate any suggestions and tips to help me out in this situation; I don't want to damage the engine..

 

[Elijah95]

Don’t waste your time with any snake fluids in the cooling system, it ruins things; I did a head gasket on my 8.3 and sent the head off for a clean up and resurfacing job. All in my front yard with basic hand tools and lots of elbow grease. Lower output 6cta engines are known for head gaskets being a weak point and if it is blown I’d bet someone was working it off-road and the shutterstat failed, not activating the fan and poof next thing you know it’s mixing fluids.

Coolant can also enter the engine oil in (3) other ways that I’m aware on an A2 truck; the oil cooler, the air compressor, the turbo after-cooler, all of which are pretty rare.

To go cheap and safe, go to your local harbor freight and pick up a coolant pressure test kit, pump up the cooling system to 15 psi and watch it close. Or if you finish changing the oil and crank it, look for lots of bubbles in the reservoir tank, if you know anyone with a carbon monoxide detector you can pop the cap with it running and use it to sniff the reservoir.

If you do end up having to do a head gasket job reach out to me and I’ll send you a picture by picture break down of everything I touched, and a complete parts list of everything you’ll need to order. If you machine the head all total you’ll be out $1000 on the high side


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[Elijah95]

Also, if at all possible I’d recommend not driving it. Coolant is kryptonite to wear surfaces, quickly wiping bearings out, once it emulsifies into the oil it will take 3-4 oil changes @ 5 gallons per change to get the water percentage level low enough in the oil to safely drive


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[levitate]

Don’t waste your time with any snake fluids in the cooling system, it ruins things; I did a head gasket on my 8.3 and sent the head off for a clean up and resurfacing job. All in my front yard with basic hand tools and lots of elbow grease. Lower output 6cta engines are known for head gaskets being a weak point and if it is blown I’d bet someone was working it off-road and the shutterstat failed, not activating the fan and poof next thing you know it’s mixing fluids.

Coolant can also enter the engine oil in (3) other ways that I’m aware on an A2 truck; the oil cooler, the air compressor, the turbo after-cooler, all of which are pretty rare.

To go cheap and safe, go to your local harbor freight and pick up a coolant pressure test kit, pump up the cooling system to 15 psi and watch it close. Or if you finish changing the oil and crank it, look for lots of bubbles in the reservoir tank, if you know anyone with a carbon monoxide detector you can pop the cap with it running and use it to sniff the reservoir.

If you do end up having to do a head gasket job reach out to me and I’ll send you a picture by picture break down of everything I touched, and a complete parts list of everything you’ll need to order. If you machine the head all total you’ll be out $1000 on the high side


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Thanks, that's great advice. If it comes to a head gasket replacement I'd love to have that picture by picture breakdown from you. I have CNC Milling lathes, so the machining would be covered.

If there is only the slightest leak, is this safe to drive ten miles back to my house with it?

What if I can't find the leak? Drive it ten miles and then dump the old to check for antifreeze?

Underlying all of the above scenarios; I don't want to damage the engine. Nor do I want to face my wife coming home having my new toy being towed. She would say "That's not turn key..." with her meanest face.

 

[Elijah95]

I gotcha covered!

If you do a cooling system pressure test, slide a clean pan under the oil drain plug and pump her up (I can’t remember, I THINK 15 psi is factory cap pressure) and see if any coolant comes rolling out and pressure drop. It could even be a cracked head on the air compressor leaking coolant down by the piston rings then into the case.

If you can’t get it to leak down period, then you should be safe with fresh oil to fire it up and limp it home, and when you get there I’d advise cooling the reservoir down with a water hose and popping the cap to avoid possibly pushing more coolant into the crankcase post shutdown. But I’m betting you’re going to see it pretty quickly under pressure

Take a spot mirror back with you and take a peak in the valve cover while you’re there


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[levitate]

I was actually wondering how many back to back oil changes would be needed, sounds like a reasonable suggestion.
Would one put the new oil in, start for 15 minutes and drain? (Repeat)
Also between each oil change would the filter need to be changed?

 

[levitate]

I gotcha covered!

If you do a cooling system pressure test, slide a clean pan under the oil drain plug and pump her up (I can’t remember, I THINK 15 psi is factory cap pressure) and see if any coolant comes rolling out and pressure drop. It could even be a cracked head on the air compressor leaking coolant down by the piston rings then into the case.

If you can’t get it to leak down period, then you should be safe with fresh oil to fire it up and limp it home, and when you get there I’d advise cooling the reservoir down with a water hose and popping the cap to avoid possibly pushing more coolant into the crankcase post shutdown. But I’m betting you’re going to see it pretty quickly under pressure

Take a spot mirror back with you and take a peak in the valve cover while you’re there


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So you suspect it's been ran this way for awhile?
I would guess that if there was antifreeze on the the valve cover the engine has been run. (Bad)
The owner was getting older so he probably just started it a few times in the last few years.

 

[simp5782]

Drain the antifreeze. Drain the oil. Refill with fresh oil and filter and run it and see if it runs bad and Or blows white smoke. Do not put antifreeze back in it

A bad oil cooler can put antifreeze into the engine oil especially if its been sitting. Being rusted thru.

 

[74M35A2]

Yikes, seeing green coolant in the oil filter makes my skin crawl. If you guys have ever rebuilt a lot of engines, you may know what coolant does to bearing surfaces, it eats them like acid, leaving a pizza-like surface behind. Don't be surprised if she starts rattling after you find and fix the coolant leak. Rare to see an 8.3L have issues, but it can and does happen, mostly from abuse (overheat, etc...). Then again, these things are not new anymore either. 30 years or such.

Simp is right that it could also be occurring at the oil cooler, although I think kind of rare on 8.3's? That is a much easier check to disassemble and inspect then changing the head gasket. Also agree on using water until you are sure you have the coolant leak fixed, for the reason of bearing etching as mentioned.

 

[WildernessJeep]

Drain the antifreeze. Drain the oil. Refill with fresh oil and filter and run it and see if it runs bad and Or blows white smoke. Do not put antifreeze back in it

A bad oil cooler can put antifreeze into the engine oil especially if its been sitting. Being rusted thru.

What's the answer to the replacement cooler? Go back factory or is there an upgrade? I think I have the same issue. No damage, I caught it just in time.

 

[Elijah95]

@WildernessJeep replace with a new stock one, they only become a problem in poorly maintained cooling systems. (Practically every military vehicle is neglected in service coolant wise)

Replace, verify problem is solved, flush cooling system, install coolant filter head bypass into heater hoses with (2) T fittings and fill up with any name brand diesel long life coolant with SCAs and never look back


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[simp5782]

What's the answer to the replacement cooler? Go back factory or is there an upgrade? I think I have the same issue. No damage, I caught it just in time.

There is no upgrade on an nhc250 truck. You can supplement an added air charged oil cooler like I did but you aren't doing what I was doing with it. I did it to get some heat off the motor along with an air charged transmission cooler and ditched the heat exchanger.

 

[levitate]

Yikes, seeing green coolant in the oil filter makes my skin crawl. If you guys have ever rebuilt a lot of engines, you may know what coolant does to bearing surfaces, it eats them like acid, leaving a pizza-like surface behind. Don't be surprised if she starts rattling after you find and fix the coolant leak. Rare to see an 8.3L have issues, but it can and does happen, mostly from abuse (overheat, etc...). Then again, these things are not new anymore either. 30 years or such.

Simp is right that it could also be occurring at the oil cooler, although I think kind of rare on 8.3's? That is a much easier check to disassemble and inspect then changing the head gasket. Also agree on using water until you are sure you have the coolant leak fixed, for the reason of bearing etching as mentioned.

Yes, seeing green ruined the joy of picking up the new rig, didn't count on the in the works.
The widow was such a nice lady I could not walk away, I already had the cashiers check in hand.

• I went out yesterday and bought a cooling system pressure test kit from NAPA; it didn't fit, so I ordered the correct kit with adapters
• I drained and flushed all of the coolant, oddly no oil in the antifreeze??
• I filled and flushed the crankcase oil several times; there was a tiny bit of green sheer when looking at the oil cap and inside the valve cover
  • This leads me to believe it's been run in this state at one point which is a bummer
  • There was only 2-3 Quarts of water in the oil; that's not enough fluid to make it up to the oil cap; I don't see any other way for it to get there
• I tried starting it and no luck; compared to my M35A2 it didn't seem to have much compression which scares me
  • Fuel seemed fine, and pressurized at the filter
  • I left the older filter on since it looked brand new and some moron screwed it on seals dry, far far more than hand-tight
  • The filter could certainly be plugged; I just didn't know if I had the right NAPA filter by looking at it, threads etc.

What seemed wonky was the Engine Emergency Stop Control cable assembly:


I reversed the wire stop in the pictures because on the other side it was free-floating.
I know I could probably find it in the manual but if someone knows off the top of their head how this setup works that would be great; I'm slammed in my day job (tech) so it's tough to research this.

1. Am I missing a spring here?
2. What is the RUN position of the Solenoid Plunger, OUT = RUN or IN = RUN?
3. There is a three wire feed to the solenoid, I'm assuming BLK = GND, RED = +24V and White = Signal
   1. Should white = HIGH (+24V) or LOW (0V) when in the RUN state?

Other potential causes for a failure to Start, in order of my worst nightmare first:

1. Cracked Block
2. Burnt Sleeves
3. Burnt Rings
4. Bad Cylinder - puncture etc.
5. Blown Head Gasket (I'd be OK with this)
6. Cylinder walls dry
7. Other Crankcase Leak - ??
8. Fuel System - Plugged Filter(s), Bad pump, Bad Fuel
9. Electrical, - Wacky Sensor
10. Throttle Body Issues, - Cables wrong, Springs missing, vacuum leak
11. I can't think of another reason, but I always try to make my lists go to eleven

Any help on getting her started would be much appreciated!

 

[levitate]

Drain the antifreeze. Drain the oil. Refill with fresh oil and filter and run it and see if it runs bad and Or blows white smoke. Do not put antifreeze back in it

A bad oil cooler can put antifreeze into the engine oil especially if its been sitting. Being rusted thru.

Thanks, I followed that plan. Unfortunately I could not get her to start to see if she blows smoke. I'm hoping it's something simple, I posted details just a few minutes ago. Any help is appreciated; I really don't want to tow it, mostly due to my ego having to bring it home that way..

 

[simp5782]

10 mm socket and pull the solenoid off and throw it away. They are junk. Flip the lever for fuel shut off up. Use the manual fuel shut off in the cab

 

[levitate]

10 mm socket and pull the solenoid off and throw it away. They are junk. Flip the lever for fuel shut off up. Use the manual fuel shut off in the cab

I'll have to hunt down those levers. What about the cables going to the solenoid, will it cause any errors being disconnected?
If so, can sensor wires be x-wired with a resistor to be in the always run state?

 

[98G]

Did it fire on ether?

Zip tie the solenoid in the run position or get rid of it entirely...

Edit - I missed the last hour's worth of posts when i first made this one. Strange.

Anyway, solenoid not required to be present. Causes no problems running without it and just using the kill cable.

 

[levitate]

Did it fire on ether?

Zip tie the solenoid in the run position or get rid of it entirely...

Edit - I missed the last hour's worth of posts when i first made this one. Strange.

Anyway, solenoid not required to be present. Causes no problems running without it and just using the kill cable.

I tired using the ether button, held for three seconds while cranking and release ether button.
I'm not sure it even had any ether in it, where is the fill bottle?

Leaving all wires open after removing the solenoid should be fine?
I'm assuming a open circuit = RUN.

On the green kill lever, I think I'm missing a spring to recoil the mechanism:


Should the green lever, have a spring?
What the lever is in it's RUN position, is this when fully Clockwise (plunger OUT) or fully Counterclockwise (plunger IN)?
What does this lever control? If it's part of the engine kill system how does it accomplish this? Fuel shutoff, open valves?

 

[simp5782]

I'll have to hunt down those levers. What about the cables going to the solenoid, will it cause any errors being disconnected?
If so, can sensor wires be x-wired with a resistor to be in the always run state?

Unplug it and let it hang. No need for anything

 

[Crf450x]

If you’re trying to check the fuel shutoff solenoid you need to bump the starter to see if it is working. One wire is ground, one is to pull it up (when started is engaged), one is to hold it up. If it doesn’t pull up on its own, leave the key on and pull it up by hand. It will probably stay there. If not, just take it off. If it’s getting fuel and has compression it will run.

By the way before you start chasing it, there is no throttle body and diesels don’t have vacuum. It doesn’t care about any sensors.

Also, if it has coolant in the oil but no oil in the coolant, that means your leak is where coolant pressure is higher than oil pressure. So you can rule out the oil cooler.