Colder than a...

[Old Sarge]

Okay, since the Texas weather went from 0 to 65 much faster than the average car, I thought I'd go out and start and check the old Case 550G today. Cranked up fine, thought, well, battery didn't die. Then smelled oil. Cut it off immediately, looked underneath, and saw that I'd lost a quart or two. Thought (thought) I had plenty of anti-freeze, since I just put in a new water pump in June, and replaced it then. Then re-thought, I did add water several times while clearing brush during summer and fall, because radiator got hot and it plugged up. Short story, took off right side cover, top freeze plug blown out. I checked fluids before starting (oil was right on the top mark, and I had marked that I changed oil in September, right after finishing brush work, and washing dirt out of radiator). I admit I only checked water in the overflow tank, because I've been running it in the heat, and I know I've had to put water (yeah, I know) in several times, but I was sure it was moving (and it was still green). Anyway, the big freeze plug let me see there was still coolant (probably not enough anti-freeze, although I could smell it, to prevent freezing at 0) in the system, but okay, I screwed up. But where did the oil come from?
I figured the block was split (I know how useful freeze plugs are, not really at all), but I checked the oil again, no sign of water, but I couldn't see the coolant in the top of the radiator. I decided to track down the oil leak figuring I either have a 7 ton paperweight, or a source of parts to list for sale. When I re-started it and quickly cut it off, I saw the oil was literally pumping out of the oil pressure relief valve.
My question after this long explanation is how could the engine freezing, or the blown out freeze plug cause excessive oil pressure without raising the level in the oil pan?

Oh, and the oil level on the dipstick dropped a corresponding amount to the oil that pumped out on the ground.

 

[Tinkerer]

Maybe take the relief valve apart and look for problem with it.
Remove the oil filter and cut it open to see if something is in it that shouldn't be.
A lot of people call expansion plugs in blocks -freeze plugs. Those plugs have nothing to do with freezing or freeze protection.
They are used to plug the holes that were put in the block to remove the sand when the block
was cast.

 

[Delmer]

Take the relief valve apart and there will be a seal cracked, or something cracked. From high oil pressure and a jammed relief valve possibly? Check it for free operation before you put it back together.

Nothing to do with the antifreeze except the cold got them both.

Core plugs work to protect from freezing as you've seen, sometimes. That's not their purpose though. Just what they get called when somebody gets lucky and doesn't crack their block.

 

[Old Sarge]

Yep, I know they aren't for freeze protection, and know they are called "expansion plugs" but, as I was growing up watching the "old guys" work on stuff, they called them "freeze plugs." Thanks for the input, I'll try taking the pressure relief valve apart, I just really couldn't figure out how freezing coolant could result in enough excessive oil pressure to blow a quart of oil out in a few seconds. (I would have expected less oil pressure from a cracked block, rather than more.)

 

[Tinkerer]

My comment about freeze plugs wasn't directed towards you in particular, Old Sarge.
There are a some people reading these posts, and a for some of them this is new to them. I keep that in mind whenever I post an opinion or comment.
It could be a coincidence that the cold temperature of the coolant and the relief valve happened at the same time. I'm sure you will sort it out.

 

[Dave Neubert]

Maybe you had some moisture in the valve and it froze and cracked pull it apart could be just a o ring

 

[Old Sarge]

Pulled the relief valve out today, looked okay, o-ring replaced, no signs of blockage, oil is still clean (only put 5 hours or less on it since oil change). Will take assembly apart tomorrow and see if the cold oil relief valve is shot. Oil was gushing out around the plug on the relief valve, and not just a trickle. I'm not big on coincidence, but maybe. I am still trying to figure what could happen to "increase" oil pressure to the point it opens the relief valve. It hit 75 degrees or more today, right now it's in the upper 50s, so everything even deep in the engine should be thawed out, although a week ago the temperature was right at zero. (Which is why everything froze, and even though I had some anti-freeze, I guess I'd diluted it enough that it wouldn't handle zero to five degrees for something like twelve hours.) I know there may be a break in the block right behind the oil-cooler/oil filter mount, but I would think there should be some sign of water in the oil. (or oil in the water, which I haven't seen either.)

 

[Tinkerer]

What was the oil pressure gauge reading when it was running ?

 

[Old Sarge]

The gauge doesn’t read in psi, when it starts, until it warms up (I am not running it to that point right now), it is at the top of the “green”, but not into the warning (yellow), and after warmup it settles in about the top 1/3 of the green area. Been like that since I bought it at an auction 5 years ago. Hour meter hasn’t worked since I have owned it, and it runs off the oil pressure gauge, so I haven’t messed with it.

 

[Old Sarge]

Should mention gauge didn’t read any higher than it has been doing, so no idea on that.

 

[Tinkerer]

It isn't unusual for a block to crack on the outside only from frozen coolant.
I've only seen one that cracked both in and out.
I don't know what the thread size is on the relief valve, but I would try to replace the valve with a pressure gauge long enough to see what it reads there.

 

[Delmer]

Do you know what is around the plug that was leaking? I'd guess there was some water trapped in the relief valve that froze, and it was a very short pressure spike that caused it to break. Sounds like the relief valve is working fine when running. I'd still take it apart and inspect, but probably nothing you could have done to predict this or prevent it, short of lower viscosity oil, block heater, oil pan heater, maybe avoiding short run times in cold weather to avoid condensation.

 

[Old Sarge]

Okay, I think (think) I've got it now. Got the oil filter/oil cooler/regulator/relief housing off (after removing a lot of other parts, but that's another story). There are a series of hairline cracks in the housing (which is a light, maybe aluminum casting? Didn't have a magnet with me to test it). One of those actually comes out under the shoulder of the cap screw at the top of the relief valve, hidden until I took the whole shebang loose, and maybe (probably) that is where the oil was pumping out when I ran it, rather than having enough pressure to overcome the spring in the relief valve. The cooler looks okay, and I don't have young eyes to inspect for ultra-thin cracks, so I guess it'll get replaced too. Now the real roll of the dice, $25K worth of small dozer versus a couple or three hundred bucks of castings and gaskets. I now suspect that there isn't a "high oil pressure" problem since there was ZERO gum or sludge in any of the oil lines on the housing or cooler, or in the ports into the engine. (I have seen worse on a lot newer engines than this early 90's built machine.)

 

[Old Sarge]

Well, not done yet. The oil cooler core is not like the one in my manual, or any of the ones I can find on the Case website or any machinery parts sites. It doesn't have a stack of "plates" on the inside part, it is simply a "U" shaped tube, about 5/8" in diameter, sticking off the back with two ports leading into the filter/cooler/relief valve housing. Anyone seen anything like that?

 

[Delmer]

How about a picture of the relief valve and the cooler? a close up of the cracks too.

I was misunderstanding this thread from the beginning. Was it already 65 degrees when you started the engine and it started leaking? I was also focusing on the relief valve, and ignoring the oil cooler which is in contact at least with the coolant.

 

[Old Sarge]

Yep, it was 65 or warmer. I should add that today reached about 80 degrees, (last Tuesday, it was 5 degrees) which kind of explains why things break. Thermal shock is a way of life around here. I've tried to attach pictures of the oil cooler, and a couple that might show the cracks. (I don't have a real camera, just my phone). The cracks are all pretty narrow, but I can tell the one by the plug goes through.

 

[Welder Dave]

Done by someone with experience cast aluminum is generally a successful weld repair using Tig. Transmission cases and oil pans are commonly welded.

 

[Delmer]

Coolant freezing 100%. Find somebody to weld it if you can. Might not be that hard to find a used part, it's not like they wear out commonly. Find the part number and parts search on machinery trader or just search engine. Or Jbweld it if you dare.

 

[Old Sarge]

Thanks for the suggestions, a used part is $95 and should be here next week, and being 30 miles from the nearest town with a "welding shop" and not having the skills or equipment to TIG weld it myself, and the fact that the majority of the cracks I can see and feel with my fingertip don't even show up on pictures, I figure $95 is a cheap and easy way out. Now, if that's the only thing wrong...

 

[Old Sarge]

Okay, I've looked high and low, and nowhere can I find an oil cooler core that looks anything like the one in the picture above (the one named "Oil cooler back". I think this one is not leaking, but I'm not sure what one loop of about 5/8" tube circling in the water jacket for about 8 inches of length is actually doing for the oil temperature. Anyone got any guesses? (Honestly, I'm probably going to put this one back in, when I get the replacement housing, just on the theory of "if it ain't broke..." I never noticed any oil problems, but that doesn't look too effective.