Oil Cooler Cracks, new oil cooler

[Heloman]

With just over 20 hours in my new 1968 C, I noticed a 3-4 inch crack in the corner radii of  the extruded C-channel-mount of my oil cooler. The sad thing is, this oil cooler is less then a year old with about 40 hours time on it. I had all the records from the purchase so I called Pacific oil cooler and while they didn't warranty it they did repair it cheaply, and in the end I'm happy with their service. At first I was a little upset they wouldn't warranty it but when they explained the reason I agreed with them, and I think it's worth mentioning here so that others might not have he same problem. I was told that the oil cooler should be mounted using long bolts that run through both "legs" of the C-channel, with pinch tubes in the center to spread the load through the entire mount, my oil cooler was mounted using short bolts through the cowling and only one "leg" of the C-channel on each side. The Mooney parts manual doesn't show any detail on this so I'm not sure I can fault anyone, but in looking through the gallery here on Mooneyspace I did see other peoples oil coolers mounted the same way mine was. A few bucks in new hardware could save you an oil cooler.

Edited March 17, 2016 by Heloman

[Shadrach]

18 minutes ago, Heloman said:

With just over 20 hours in my new 1968 C, I noticed a 3-4 inch crack in the corner radii of  the extruded C-channel-mount of my oil cooler. The sad thing is, this oil cooler is less then a year old with about 40 hours time on it. I had all the records from the purchase so I called Pacific oil cooler and while they didn't warranty it they did repair it cheaply, and in the end I'm happy with their service. At first I was a little upset they wouldn't warranty it but when they explained the reason I agreed with them, and I think it's worth mentioning here so that others might not have he same problem. I was told that the oil cooler should be mounted using long bolts that run through both "legs" of the C-channel, with pinch tubes in the center to spread the load through the entire mount, my oil cooler was mounted using short bolts through the cowling and only one "leg" of the C-channel on each side. The Mooney parts manual doesn't show any detail on this so I'm not sure I can fault anyone, but in looking through the gallery here on Mooneyspace I did see other peoples oil coolers mounted the same way mine was. A few bucks in new hardware could save you an oil cooler.

Mine is not mounted with long bolts. It had short bolts and washers with nuts on the back of the side of the "C Chanel" that butts against the cowl. I am 99% sure that is how it came from the factory. Several years ago we fabricated a nut-plates fit in the "C-Chanel". It's much easier to mount with the nut-plates.

[Heloman]

Just now, Shadrach said:

Mine is not mounted with long bolts. It had short bolts and washers with nuts on the back of the side of the "C Chanel" that butts against the cowl. I am 99% sure that is how it came from the factory. Several years ago we fabricated a nut-plates fit in the "C-Chanel". It's much easier to mount with the nut-plates.

Yes, nut plates would be nice, long bolts and fiddling with pinch tubes isn't going to make things easier.

[N601RX]

I noticed this a few years ago also.  When my 67F still had the oil cooler in the original location it had long bolts and spacers, but the parts manual only showed An3-4A bolts and washers which are only long enough to mount to one side. When I ordered the LASAR relocation kit it came with long bolts and spacers. 

[Shadrach]

If the pinch tubes are the proper way to mount it, I don't understand why they aren't permanently welded in place.

[Yetti]

Not that my plane is right, but it has the long bolts with a long piece of sheet alum with rivanuts in the plate.   It is kind of a pain to get everything lined up on install so I could see where others might take a short (get it short bolts) cut and not use the spacer tubes.  The spacer tubes look like standard AN hardware.  Given that you are mounting a flat thing to a rounded shape there would be lots of chance tor deformation and cracking.  Add some vibration for good measure.   Might want to have a conversation with the installer

[Heloman]

1 hour ago, N601RX said:

I noticed this a few years ago also.  When my 67F still had the oil cooler in the original location it had long bolts and spacers, but the parts manual only showed An3-4A bolts and washers which are only long enough to mount to one side. When I ordered the LASAR relocation kit it came with long bolts and spacers. 

No relocation kit for the C-model...I see the spacers in the picture on the website.

[N601RX]

Do you have these doubler plates installed? 

http://www.mooney.com/en/sb/M20-99.pdf

here is another cause of cracking.  Does your oil cooler lines go up through the engine baffling, or down under the exhaust?

http://www.mooney.com/en/sb/M20-110.pdf

[Shadrach]

The Mooney MX manual does not call for pinch tubes and long bolts.

 

[Yetti]

Depends on the MX manual.... 205 does.  Also remember there is a SB on some of the S&W oil coolers so there may be an update there.  They are shown in the drawing, but don't appear on the parts list....

 

 

[RLCarter]

My 65 "E" has the long bolts, pinch tube and the doublers, there are 2 AD's on the oil coolers that I am aware of.

 

[mike20papa]

One of the first comments my A&P made when he first looked over my A model was a comment to upgrade the oil cooler install with compression tubes and AN3 flat washers at each end to make a "spool".  I added the floating tee nuts for convenience during the annual.  The washers are a trick to get to stay in place when assembling, but after about 500hr.s, no problems with cracks in the oil cooler flanges.

[carusoam]

Heloman,

nicely documented problem and solution.

Everyone else, nicely documented updated easy to understand installation ideas!

Nothing changes your day like a Mooney engine running out of oil at altitude...

Best regards,

-a-

[PMcClure]

A little off topic, but I ran into this on my Ovation IO550. The oil cooler had cracks on the mounting flanges. It was factory installed. We replaced with an overhauled unit.  I haven't dug into the issue much but it has me thinking. 

[carusoam]

PMc,

What year is your O?

The first few dozen may have got an AD to change the oil cooler back in the day.  Those cracks let oil out in flight...

Its been a few years since I did the research on the issue and my memory has aged (a lot).

Best regards,

-a-

[PMcClure]

14 minutes ago, carusoam said:

PMc,

What year is your O?

The first few dozen may have got an AD to change the oil cooler back in the day.  Those cracks let oil out in flight...

Its been a few years since I did the research on the issue and my memory has aged (a lot).

Best regards,

-a-

2002 #285. I haven't seen anything on a AD. You have anything? Lots of thoughts I have: 1) what could have happened? 2) why did it happen? 3) was this the cause of my oil consumption? 4) are others having this issue?

The cracks were very hard to see and look to be caused by the design and mounting. Can't imagine mine is unique but didn't see any oil leaks. 

[carusoam]

My bird is listed in the FAA files back in 1994 with a couple other early Os and a handful of Cirri.  They were draining oil overboard.

Whatever quality issue happened to the oil cooler back then shouldn't be a problem in the new millennium.

Best regards,

-a-

[hoot777]

Have replaced the oil cooler once since 68 G model purchased in 2013. The housing around the cooler has had lots of work done over the years. I see a 6 inch beef plate on one side. I am finishing the annual and A n P had to make bracket for one of the bolts to beef it up.  We suspect the weight of the oil and all the vibration contributes to this area getting beat up.  

[47U]

14 hours ago, hoot777 said:

I see a 6 inch beef plate on one side. I am finishing the annual and A n P had to make bracket for one of the bolts to beef it up.  We suspect the weight of the oil and all the vibration contributes to this area getting beat up.  

Continuing the revival of this post… 

In 2010, Dan sold me a new oil cooler mount ‘Bracket’ pn 650017-000 REV G which is much thicker aluminum than the original.  No issues since.  

The IPC Manual 205 also lists pn 650049-000, but I’m not sure what that’s about.