Oil Coolers

I'd have to look at the spec, but an oil cooler is probably
pressure tested / designed to hold at 400-500 PSI. Since
the oil pressure is regulated at 35-90 PSI there is a good
margin for minor oil pressure spikes. But the oil pump can
far exceed that if the relief valve is stuck, it can produce
oil pressures as high as a good hydraulic pump, just not the
volume.

Nice to have a report on a company.



"Robert M. Gary" wrote in message
ups.com...
|
| Jim Burns wrote:
| In addition to JimM's great information, check out
| http://www.oilcoolers.com/ , Pacific Oil Cooler Service.
Lots of good info
| there. If you get to OSH next summer, look them up.
You'll be amazed at
| how much crud can accumulate in your oil cooler.
|
| I had these guys O/H my Mooneys oil cooler and haven't had
any
| problems.
|
| -Robert
|

Jim Macklin wrote:
I'd have to look at the spec, but an oil cooler is probably
pressure tested / designed to hold at 400-500 PSI. Since
the oil pressure is regulated at 35-90 PSI there is a good
margin for minor oil pressure spikes. But the oil pump can
far exceed that if the relief valve is stuck, it can produce
oil pressures as high as a good hydraulic pump, just not the
volume.

Many engines have the oil pressure relief valve at the far end of the
lubrication system so that pressure is maintained to all parts even
when oil is cold and reluctant to flow. Other systems have a relief
valve in the pump itself, like an automobile's, which might open and
dump the pressure if the oil is too thick, reducing flow to other
components down the line but saving the cooler.
Many systems have a temperature valve that bypasses the oil cooler
until the oil warms up. The pressure is still there against the cooler
because it's plumbed into the system, but the pressure on the two lines
is equal and oil doesn't flow until the bypass closes. With the cold
oil being reluctant to flow into the system from the pump, and the
relief valve way down at the end of the line waiting for pressure, the
oil cooler can get a pressure spike that swells the channels in it. The
expanded metal can sometimes be seen if the cooler is off and a light
shone through the fins. Enough swelling and they split.

Dan

unicate wrote:
In October, after an extensive repair/restoration of my airplane, the
oil cooler split on start-up and dumped most of the oil. Long story, but
the engine seized up 6 minutes into the flight and we did an emergency
landing in the desert. We were very fortunate to walk away with minor
injuries, but the plane was totaled.

To the airplane owners out there, how often do you flush/pressure test
or replace your oil cooler? Some say it's only done at a major overhaul,
others say it should be done at every annual, others say only if there's
a problem w/oil pressure. I had never heard of an oil cooler failing
before this, but now I've heard people say it happens on occasion.

After replacing the oil cooler you should have done at least a 10
minute ground run with someone outside watching for oil leaks. Same
procedure as for an oil change.

-RObert

"Robert M. Gary" wrote:

To the airplane owners out there, how often do you flush/pressure test
or replace your oil cooler? Some say it's only done at a major overhaul,
others say it should be done at every annual, others say only if there's
a problem w/oil pressure. I had never heard of an oil cooler failing
before this, but now I've heard people say it happens on occasion.

After replacing the oil cooler you should have done at least a 10
minute ground run with someone outside watching for oil leaks. Same
procedure as for an oil change.

We did not replace the oil cooler, it was not disturbed throughout the
entire repair, which is part of the reason for my question. *Of course*
we did ground-run tests after the engine repair, and at 8 hours after
the repair when we replace the mineral oil with Aeroshell 100. No leaks
were present, either time. My question was, SHOULD the oil cooler have
been flushed/pressure tested since a major repair had been done, and/or
how often do mechanics generally recommend that this be done?

Shirl

unicate wrote:
"Robert M. Gary" wrote:
We did not replace the oil cooler, it was not disturbed throughout the
entire repair, which is part of the reason for my question. *Of course*
we did ground-run tests after the engine repair, and at 8 hours after
the repair when we replace the mineral oil with Aeroshell 100. No leaks
were present, either time. My question was, SHOULD the oil cooler have
been flushed/pressure tested since a major repair had been done, and/or
how often do mechanics generally recommend that this be done?

When Pacific Oil Coolers returned my after cleaning it out they
included a description of the flush and pressure test they did.

wrote in message
...
In October, after an extensive repair/restoration of my airplane, the
oil cooler split on start-up and dumped most of the oil. Long story, but
the engine seized up 6 minutes into the flight and we did an emergency
landing in the desert. We were very fortunate to walk away with minor
injuries, but the plane was totaled.

To the airplane owners out there, how often do you flush/pressure test
or replace your oil cooler? Some say it's only done at a major overhaul,
others say it should be done at every annual, others say only if there's
a problem w/oil pressure. I had never heard of an oil cooler failing
before this, but now I've heard people say it happens on occasion.

Anyone else here have experience with this?

Shirl

A friend had one split in a 2 year old Mooney 201 over Eastern Oregon
desert. We went to Boise to pick up an Aztec, and decided to fly "together"
on the way home. (Medford,Or) 20 Minutes out of Boise, I had been flying
his right wing, and gradually slipped under/behind to the left side. He had
a 2 foot side black stripe from the cowling to the tail. We turned a bit to
the right to divert to Baker, and he had normal pressure and slightly rising
temps as we landed. I think he still had almost 2 qts left in the 700 hr tt
engine. I always wondered what would have happened if we hadn't stuck
together that day.

Al G