Usually I search the Forum before asking, usually find the answer.  Breaking protocol this time and asking first - small panic.

 

1995 12 valve 5 speed, 576k miles.

 

On the way home from work last night, noted temp guage a little higher than typical, not high but not where it sits normally.

 

This morning, found radiator cooland about 1-2" lower than filler neck, some oily-looking emulsion in it.  Immediately thought "head gasket!"

 

Oil level on dipstick a little low - half quart or so, only ~1,500 miles since last oil change.  No sign of coolant / bubbles on dipstick.

 

Pressure tested radiator, holds pressure.  Radiator cap does not - it is bad.

 

Ashamed here... if it were 10-15 years ago my brain would be less rotten and I'd know what was wrong, or what the next test would be to do, or how to proceed.

 

Unfortunately the only thing I can think of is a cylinder leakdown test and I 1) dont have the gauges and 2) don't know how to do it on a diesel.

 

Maybe I should leave the cap off, start the engine, and look for bubbles in the coolant as it flows by the neck?

 

Any of y'all want to point me in the right direction?

 

Thanks in advance.

 

 

Yep look for bubbles in the coolant at idle but, don't drive it if there are, as you'll cause more damage to the engine. I hope it is a simple head gasket. My 92 is approaching 500 k miles. No problems yet.

Does your truck have an oil/water cooler?  Known to fail.  Think they're on transmission... 

no bubbles so far, waiting for thermostat to open.

 

I think oil cooler is only on auto trans, not maual - have to check - thanls!

flagmanruss, thanks.  the service manual shows an engine oil cooler that lives in a recess in the block, behind the oil filter.  Never knew - I've only had this truck for 20 years - that such a thing existed.  On my way to read up on it.

 

no bubbles in the coolant, looking in the radiator filler neck.

 

thanks again,,,

I don't know if it is alright to post links to other forums here.  If not, please excuse me and please delete this.

 

http://www.dieseltruckresource.com/forums/1st-gen-ram-all-topics-93/oil-cooler-removal-133253/

 

this is simpler and cheaper than pulling the head, there is no reason to suspect the head gasket over this cooler, and I think taking it out and testing it is a lot simpler than the head.

 

And they told us at work we can't carry vacation days over to next year, use them or loose them...

All trucks have the oil cooler which is behind the oil filter mount. These can leak and generally it pushes oil into the coolant since the oil pressure is higher than coolant pressure. They also have different degrees of leaks and a small one can be self sealing as coolant/oil temp rises.

An oil cooler leak doesn't describe the coolant loss thou.

Understood, thanks!

 

I think I can attribute the coolant loss to the cap, that only holds about 7 psi - but the lost coolant should have gone into the overflow bottle I think.

 

I did find the oil cooler, gunked it all down in preparation to take it apart.  Book says test with 70 psi air, the 15-17 psi I put on the radiator held but probably wasn't enough.

 

However, now I'm feeling like a fool and thinking maybe  the only thing wrong is I mixed two brands of antifreeze - most of a bottle left over at the barn from the last time I did hoses (about two years ago), with new, when I changed the water pump in like April (?).  The leftover stuff was red or orange, the new was green, and I didn't think about it - but doing some reading, that was not smart.

 

So tomorrow I drain, flush, refill with just water, and see.  If it is ok I'll drain and refill with the right coolant and watch it like a hawk for a while.

 

I was also wrong about the oil level.  After sitting, it was not low, it is right where I filled it to when I changed the oil three weeks ago.

 

Anyway, thanks for the hand-holding y'all.  It is one thing to help else someone with a problem, but when it is my truck I tend to get emotional and irrational, and that does not help reasoning out the possible causes and figuring the next steps.

I fully understand. The older I get the more it seems I'm always looking thru a cloud of smoke trying to reason out why something happened that shouldn't.

 

I'm glad you posted here and bounced it off us to think it through.

Flush it good and add more coolant than water for the water that gets trapped in the block when flushing. I switched from green to orange (HOAT) and after a couple months I had scaling in the system. I flushed it again and added more uncut coolant than water and haven't had scaling since. 

Flushed four times today in between regular life chores.

 

Still milky, no bubbles (probably not head gasket) so tomorrow the oil cooler comes out for inspection.  Does not look all that hard to get to - famous last words.

 

Found new oil cooler online a number of places from $122 to $355 (all same part number), not clear if the gaskets come with or not but I found part numbers for them, too.

 

Do y'all have any "favorite" places to order such parts?  Most times I can get what I need at the local auto parts store, but drew a blank on this one.

 

Thanks!

For something Like that I prefer genuine cummins parts, pulling the oil cooler out is pretty straight forward, just a bunch of bolts to take out. Back when I blew a head gasket on my truck I pulled the oil cooler out and plugged one hole and put a blow gun with a rubber tip in the other and while blowing pressure in it I submersed it in a tub of water, I didn't get any bubbles though.

Thanks!

 

It was indeed straightforward, it is on the bench ready to test - I have to find something to plug one hole with.

 

From the rotten appearance of the inner gasket, the cooler may not be leaking, it may be just the gasket, but best to check it best I can.

 

Thanks again!

I had a Volvo Penta I/O boat motor. Chased water in the oil for a long time. Ended up being the cooler. Anytime you've got oil and water in the same component, you're asking for trouble. I'd go there before pulling the head for sure!

I see the oil coolers are only about $100. If you take yours off, I'd just replace it. See if that fixes the problem and you will most likely never have to worry about that part again.

Another reason to do the frequent cooling system flush and fluid replacement as Michael recommends.

Fixed, as far as I can tell now.

 

Cooler came day before yesterday, gaskets came yesterday evening.  Put it together this morning, was disgusted when the coolant (just water I filled it with) looked milky, but kept draining and refilling and it is pretty clear now.

 

Am going to drain and refill again, but having trouble deciding (no, that's a lie) whether to replace upper and lower hoses, then refill.  But they are only 2 years old and show no signs of deterioration, so they stay, I drain once or twice more, then fill with antifreeze and top up with whatever water it needs after getting the specified 2 gallons of green stuff.

 

You know what they call "paralysis by analysis"?  It is the jackass standing between two hay bales, who starves to death because he can't decide which one to eat.

 

If its fixed, its fixed - how much more fixed is it going to get if I keep on messing with it?

Best way to flush a coolant system with oil in it is to mix powdered non-citrus cascade dishwasher powder in a pail of warm water and dissolve it and fill the radiator with the mixture and top off with water and run to operating temps and do this several times until system is clean. The only recommended way of doing it as per several engine mfg's.

...let me look - cascade....

...let me look - cascade....

 

Non Citrus only, the acid in citrus dish soap will deteriorate the rubber in hoses.

Update: flushed until clean, refilled with coolant, all seemed well, took it for a run, and long-story-short same symptoms - oil in coolant after a 20 mile run.

 

Called a local diesel guy (who came highly recommended by a guy at work) and talked to him about it.  He says if it isn't the oil cooler it is not a head gasket or cracked head, it is a cracked block.  Says these engines are known for that - first I've heard of it.

 

Have any of y'all heard of a 12-valve block cracking after 500k miles?  The only thing I can think of is a couple months ago the water pump failed, I stopped and it went home on a flat-bed tow truck since I was afraid of cooking it trying to limp home.

 

Very bummed out, looking for your thoughts on the likelihood of a cracked block, other possible diagnoses.

 

...and am going to start a thread in the "general" forum about "what would you look for" in terms of transportation.

I would lean towards an eroded head gasket.  Pull the head and have it inspected and look over the block which I would highly doubt is the issue, then install a new head gasket, @ that mileage I was leaning that way anyhow but didn't see this thread in time as I was on the road for a week and half and never checked the net.

 

Oil coolers don't generally weep a bit of oil they usually fail all together and flood the system with oil pretty quick.

Thank you!

 

I need to ask the guy exactly where the crack is, if he is so sure it is a cracked block.

 

Pulling the head seems like the right next step.

 

This truck has given me 20 years of service and I'm not going to give up on it easily - but I'm not wedded to it.

 

When people at work ask me why I don't "get a new truck" I tell them I need to know how far this one will go, and what will finally do it in.  Just like me - but unless I die in my sleep, I'll know what got me.

 

So if this is the end, ok; but "it ain't over 'till it's over" and pulling the head is the logical next step.

 

Andrew

 

Edited to add:

 

Please disregard, I think it really is fixed and the last puke of yellow emulsion I saw in the overflow tank must have been what was left in the system after all the flushing, and collected in the filler neck.

 

Once it cooled enough to remove the cap, the liquid under a thin film of yellow was green coolant, exactly what should be there.

...and the oil level is not down - if it is missing any, it is less than the thickness of the line on the dipstick.

Moral of the story - don't listen to me, sometimes I panic, especially when it is about my truck.

After the smoke clears (in a few days) I'll post an update.

Thanks for all the hand-holding and technical advice.  It is my first and only diesel.
 

Edited August 14, 20159 yr by BobCat