Oil cooler thread problem

Lionclaw · #1 01-30-2010, 10:55 AM

I'm trying to run my oil hoses and I ran into a problem with my oil cooler. The fitting on the top tightens up nicely. The threads on the other fitting bottom out before tightening up. I tried swapping the fittings with the same result. I bought the oil cooler here on VAF in a classifieds posting. Am I doing something wrong, or did I get a bum oil cooler?

BTW, before anyone says anything, that notch is just rough cut :-p

robertahegy · #2 01-30-2010, 01:23 PM

It's possible the threads were cut too deep in the offending port allowing the fitting to screw in too deep. Pipe thread is tapered. I normally do not suggest using teflon tape sealant, but in this case, it might help. Just be carefull to wrap it in a direction that won't allow it to unravel as you screw it into the port. Make sure the tail of the tape trails as you thread the fitting in and not lead.

Roberta

Walt · #3 01-30-2010, 01:50 PM

Sounds like an easy choice to me.. new SW cooler.

Get it repaired or get a new one; please no sealer, tape, safety wire, super glue, epoxy etc..

jetjok · #4 01-30-2010, 01:53 PM

This is likely not what you want to hear, but it is quite likely that your cooler is kaput (technical term). I clipped this from a blog on aircraft oil coolers;

When pipe-threads are involved, be sure that the fitting is going to snug down and achieve a seal before the shoulders above the threaded portion of the fitting come in contact with the top of the boss on the cooler. When the shoulders on the fitting touch - or come anywhere close to - the top of the oil cooler?s boss before a seal is made, it means that the threads in the cooler have lost their taper and the cooler must be replaced.

I respectfully submit that Teflon tape has no place on an aircraft engine, period. There are many liquid and paste lubes that are suited for hydraulic, fuel, oil, and air applications. Spend a few moments reading about failed vacuum pumps, plugged fuel, oil, and hydraulic lines, and form your own opinion if you would want to be flying with it. A quick search reveals that there are some who endorse the practice, but most experts that I checked with state unequivocally that Teflon tape should not be used.

jetjok · #5 01-30-2010, 02:02 PM

Quote:

Originally Posted by Walt

Sounds like an easy choice to me.. new SW cooler.

Get it repaired or get a new one; please no sealer, tape, safety wire, super glue, epoxy etc..

Thanks, Walt! I agree with you completely!

Lionclaw · #6 01-30-2010, 03:32 PM

Thanks for the quick responses. I was really bummed when I discovered this, but oh well, just gotta build on. I e-mailed the person I bought it from and he said it came from Van's. I'll give them a call on Monday and see if they can do anything about it. Otherwise I'll just buy a new one at Spruce.

Ron B. · #7 01-30-2010, 03:54 PM

You might want to try a steel fitting (if steel on a cooler is ok), I find that the threads on a steel fitting are a little larger. They tend to have less threads in the female hole, so it might tighten up?

robertahegy · #8 01-30-2010, 04:58 PM

I do agree about "no tape". Some people swear by it, some (me included) swear at it. I suggested it as a last resort. I had no tape in my RV anywhere and would never use it personally. I must have had a fit of maddness

Please forgive me.

Roberta

Lionclaw · #9 01-30-2010, 06:46 PM

The fittings in the picture are steel. I tried fitting an aluminum nipple i had and it bottoms out as well. I received a few tips to try a JIC fitting. I'll see if I can find a shop locally that sells them.

rjcthree · #10 01-30-2010, 06:52 PM

JIC should go, the taper is slightly different. Not sure what fittings you have, if you've NPT, NPTF might also be a choice. If memory serves, the NPTF threads finish at a larger radius, allowing NPT to bottom earlier, which is what you want, the converse is also true. Old hydraulics trick a old CAT tech taught me.

Rick 90432