Oil cooler repair - help needed...
 

Yesterday, my dad and I tackled the oil cooler line replacement project. It started out well, we were able to get the fitting off the oil housing with no problems (thanks Dieselgiant for the tip on the special tool).

Then, the upper one on the oil cooler itself came off with no problems whatsoever... but the lower line on the cooler was stuck rock hard - using plenty of PB Blaster, and gently trying to persuade it only resulted in stripped threads - see the photo. So now I have another project - fixing the threaded nipple.

Reading through some of the posts on this forum, I was able to find an excellent thread on the topic: http://www.peachparts.com/shopforum/tech-help/104244-oil-cooler-fittings-replaceable-themselves.html

I ordered the parts from my local dealer (I guess nobody in CO carries it) - the part referenced in the thread was # 915013-013002. Should arrive on Tuesday, meanwhile, questions on the actual repair for those of you who fought through this already: what are some of the steps for installing the patch fitting. Reading below it seems we need to cut off the nipple with the stripped threads back to the nut that's permanently attached to the cooler - that's clear, but drilling a pilot hole is confusing me... Why would we need to drill a pilot hole - isn't there already a big hole in the place where we just cut the nipple?! Wouldn't we just tap the big gaping hole in the oil cooler? Obviously I'm missing something.... and any help here would be appreciated -


Here is the direct quote from someone on the above thread:
"... All I had to do is cut the aluminum threads off the oil cooler, drill a pilot hole, tap new threads, and install the new fittings. The thread tap size is 18mm by 1.5mm. The drill size for the pilot hole is 21/32 inches, I don't know the metric equivalent. It took a local machinist 15 minutes to cut off the aluminum threads back to the nut part, drill the pilot holes (there's plenty of metal there), and tap the new threads. It took longer to rinse out all the aluminum filings and grit out of the cooler than it did to work on it. Here are the MB part numbers for the threaded oil line fittings and copper washers. MB Part # Description 915013-013002 Screwed Nipples (That's what the label said.) 007603-018101 Ring, General, Metal"

I assume the 'big gaping hole' is not quite big enough and needs to be enlarged to accept the tap.

Still not quite clear...
 

Understand, but why would there be a mention of needing a pilot hole... that's the confusion I guess. Will probably get a better feel for the job when the part arrives...

Pilot Hole might be just a bad choice of terms; Every Tap has a certain size drill that you are supposed to use. If the drill is too big the there will not be enough metal left on the threads that the Tap cuts. If the drill is too small the Tap will not fit into the hole and you will have trouble getting it started or can bind the Tap in the hole and end up breaking the Tap.

You might try this if you think the threads that are left can be restored.
See Post #13:
http://www.peachparts.com/shopforum/diesel-discussion/214122-striped-threads-oil-cooler.html

Looks like only one option left...
 

I just went out and measured the nipple with a metric caliper - looks like there is only 21.5 mm left on the nipple and the fix requires a 22 mm dye - so looks like this won't work for me - too bad - would have been easier and cleaner. Thanks though...

Since I'll be pursuing cutting off the nipple at the nut and tapping the hole I'll need to clean the shavings and such out of the oil cooler after the fact. What's a good substance to use for - is common Brake Cleaner ok for that job?!

Fill the grooves of the drill bit with Wheel Bearing Grease and a lot of the chips will get trapped in the grease. Do the same with the Tap.

The good news is that the Oil that Goes through the Oil Cooler is un-filtered Oil.
The Oil returning from the Oil Cooler goes back to the filter housing to pass through the Oil Filter before going into the Engine.

If you mean what to soak the whole Oil Cooler in; I believe I have read members have used Diesel Fuel or Biodiesel.

Brake Cleaner would work but I am not sure if you mean to Spray it from Spray Can or use it as a flush from a 1 gallon can?

If you are going to get a Gallon of Brake Cleaner you could just as well buy 1 Gallon of Slovent instead.

I believe all of the above will work.

Flushing out...
 

Grease - that's a good tip.. For the Brake Cleaner I was just thinking about buying few spray cans of that and flushing out the cooler that way... didn't know you could buy a Gallon of that stuff... :) hmmm... maybe regular liquid from a bottle (NOT under pressure) would be a little easier to control in flushing out whatever remains in the cooler after drilling/tapping... I'll need to decide.

Finally, thanks for clarifying that the oil in the cooler is pre-filtered - that's great news. Was wondering about that myself.

Thanks for your help - appreciate it.

after you tap out the hole, flush the oil cooler from the top, and as the brake clean or what ever liquid you use, will flush the chips out. then nothing gets into the oil system.

There was a thread where the guy had pictures of doing the repair, wish I could remember who that was. It was over a year back.

Charlie

I believe "pre-filtered" would mean the Oil if filtered before it goes into the Oil Cooler. That is not the case; dirty Oil goes into the Oil Cooler and dirty Oil comes outof the Oil Cooler and goes back into the Oil filter housing to be filtered.
This means that the Oil Filter will protect your Engine from any chips that might get missed after flushing out the Oil Cooler.

Correcting...
 

Yes, understand - I just didn't pick the right words, but I'm glad the filter is in line to protect the engine.

"pilot hole" should have been "tap drill hole". You may want to verify the 18 x 1.5 size, I was not able to find it in the chart below..

http://www.newmantools.com/tapdrill.htm

Tools...
 

Found this: http://www.restockit.com/High-Carbon-Steel-Metric-Thread-Spark-Plug-Tap-Plug-18-mm-1-50-(VER21164).html

Says it's 18mm x 1.5 mm and the drill size is 21/32nd - hoping that's the one.... I'll need to try it out on something first.

I'd just find a replacement at the JY.

-From the guy with too many spare parts JIC.

FYI
 

More general data on the hose replacement issue. :D

Engine oil cooler line issue link thread
http://www.peachparts.com/shopforum/diesel-discussion/211352-engine-oil-cooler-hose-line-issue-link-thread.html






Have a great day..

The Tap sold at OSH Hardware for about $13 is made by Vermont America (made in Japan) and I believe it has the Drill Size in the upper Left corner of cardboard it hangs on.

When I looked at several Tap Drill charts I found that all of them did not agree with each other. But, the drill I bought is the one that at least 2 members have actually used. So the one actually used by the members must have worked.