939 oil cooler pressure test

[jw4x4]

Here is how we tested a 939 series NHC 250 oil cooler. Utilized two 4" schedule 40 plugs, one of which was outfitted with a threaded steel valve stem. To get the plugs to seal, we used a rubber gasket from a shower enclosure floor drain in one end and a seal (which had a handy skirt) from a fuel pump module on the other end. It was a bit tricky, but we managed to get it all sealed with a small ratchet strap (bar clamps would have been ideal). It held 15 psi and was submerged in water. The leak was instantly identified- in a solder joint. A new cooler and gaskets/seals/o-rings is on the way.

 

[jw4x4]

more pics

 

[doghead]

What led up to this ingenious test tool?

 

[gimpyrobb]

JW, I have the brass packing retainer,
PN 110827
cage 15434
nsn 5330.00.785.7894

 

[jw4x4]

Necessity is the mother of invention. I just had to know if it was the culprit or not. I cannot take full credit for this set-up. Mike Evens (aka The Wizzard) searched his garage high and low to find something to get it sealed.

 

[jw4x4]

I should have mentioned that my 932 spewed choclate milk out of the coolant reservoir last week. That led to the removal of the oil cooler for investigation.

 

[jw4x4]

JW, I have the brass packing retainer,
PN 110827
cage 15434
nsn 5330.00.785.7894

I ordered everything to re-assemble. Was very reasonable.

 

[nf6x]

Nice trick! Did it look practical to resolder the leaking joint?

 

[Recovry4x4]

Very nice Jerry. I knew that you and Mike would devise a way to pressurize that unit and sink it. Sounds like you will be underway by weeks end.

 

[swbradley1]

Good grief Jerry, I was going to ask you if you wanted to follow us over to recover my new (to me) 813 this weekend just in case we need a tow.

 

[rrrr]

Great info !

 

[WillWagner]

Was it leaking?

 

[jw4x4]

Nice trick! Did it look practical to resolder the leaking joint?

It was leaking at a solder joint. I could repair it, (even block off the bad tube) but I just don't trust it. I got a new one for piece of mind. The new unit looks far more better built, especially the ends.

 

[jw4x4]

Was it leaking?

Yes it sure was leaking. I have never been so glad to see something leak in all my life!!!! All of the new parts showed up today. Gonna re-assemble it and start the flushing.

 

[flibob]

I am in the process of replacing my oilcooler also. TM says to aline index marks when reassembling. Where are the index marks?

Thanks

 

[swbradley1]

Great. Did you get it fixed? You want to follow us over tomorrow for the recovery?

 

[jw4x4]

Great. Did you get it fixed? You want to follow us over tomorrow for the recovery?
I have all new parts. Gonna install them Sat. morning then start the flushing.

I am in the process of replacing my oilcooler also. TM says to aline index marks when reassembling. Where are the index marks?

Thanks

Look real close at the end of the cooler element. There is a small dot on one end. Line that dot up with the arrow/slash mark located on the element housing.

 

[jw4x4]

Great. Did you get it fixed? You want to follow us over tomorrow for the recovery?

When I met Larry @ the BMV and he asked me about that truck, I said I could have it sold with one phone call. Well, it was one text and a phone call.

 

[flibob]

Thanks for the alignment info. Now to get rid of the oil. I flushed it twice with some dishwasher soap added and it looks better but a couple of times more won't hurt

 

[swbradley1]

When I met Larry @ the BMV and he asked me about that truck, I said I could have it sold with one phone call. Well, it was one text and a phone call.

Okay, so it took one of each, I still want to know if you want to go this morning to pick it up?

Not kidding.