Failed Oil Cooler?

[Baz]

Originally Posted by Gav

I use an earls cooler up front for the trans cooler on mine too Baz, I have a stall converter fitted to my 4L65e that produces more heat than a standard trans and have had no cooling issues even on track days and 40+C days.
Pressure wise I don't know what they are capable of, yours should be no different to mine.

Thanks Gav,

I'm asking this because last Tuesday, I blew my Oil Cooler to smitherines. Dropped about 4 litres of transmission oil over 100 metres and you should have seen the white smoke from the oil on the exhausts out the back. I thought my dream car was going up in smoke. The new Oil Cooler had only done a little over 1,000 ks and the transmission was running at normal operating temperatures when the Cooler let go. Maybe it was just a lemon of an Oil Cooler. The tow home cost me $200.

That's why I am trying to find out if anyone else has has a similar problem. I was running an 11 row Derale Oil Cooler at the time.

Baz

[Philm]

Hi Baz
Where did it fail?

Phil

[Krait]

Had an engine oil cooler on a rally car crack once. We redesigned the mounting to provide more compliance and no more dramas. A real low pressure oil light came in handy that night.

Cheers

[cbreez]

Most of the time an automatic transmission cooler line will not have the same pressures as elsewhere in the transmission. Many areas of the transmission have very little or no pressure ie: the sump which is where most cooler lines return to. I would say that you had a defective cooler. Earl's has been around a long time. It's not likely a faulty design.

[Baz]

Originally Posted by Philm

Hi Baz
Where did it fail?

Phil

Still investigating that Phil. Will let you know when we find out.


Baz

[Ant]

I have a mocal oil cooler that I am going to fit in either the engine pressure side or the scavenge side of my oil system, and use a Canton thermostat so the cold oil pressure wave at startup goes into the block and not destroy the oil cooler.

[suthol]

G'day Baz,

Probably telling you how to suck eggs but these coolers must be mounted top and bottom.

They can blow apart and if the pressure don't get them the vibration eventually will.

[Baz]

Originally Posted by suthol

G'day Baz,

Probably telling you how to suck eggs but these coolers must be mounted top and bottom.

They can blow apart and if the pressure don't get them the vibration eventually will.

Thanks Dave, I have mine mounted as you suggest. Possibly just a one off lemon. I will advise the results of the post mortem shortly.

Baz

[Philm]

Hey Baz,
If I had to guess, the fittings into the cooler were overtightened and this weakened/ cracked the unit, then a bit of vibration, heat and pressure then the weakness failed.

Phil

[vector1]

i had an oil cooler on the front shoot craps, started leaking, luckily it was not pressurized oil into the engine but scavenge oil, don't know why, never did find out.

Originally Posted by Ant

I have a mocal oil cooler that I am going to fit in either the engine pressure side or the scavenge side of my oil system, and use a Canton thermostat so the cold oil pressure wave at startup goes into the block and not destroy the oil cooler.

ant, could you explain the cold oil pressure wave? my dry sump would run 230 deg with 12 qts oil and no oil cooler street driving scavenge oil going directly into the tank, with cooler it was about 150 deg. driving around normally, will have to make a shield.

[Ant]

Originally Posted by vector1

i had an oil cooler on the front shoot craps, started leaking, luckily it was not pressurized oil into the engine but scavenge oil, don't know why, never did find out.



ant, could you explain the cold oil pressure wave? my dry sump would run 230 deg with 12 qts oil and no oil cooler street driving scavenge oil going directly into the tank, with cooler it was about 150 deg. driving around normally, will have to make a shield.

When you start a dry sump engine there is potential for the oil cooler to fail due to a problem when the oil from the oil tank drains into the engine by gravity and the oil tank level can be high enough to cause a head, and on startup the scavenge sections suck an amount of cold oil from the oil pan and force it through the oil cooler, I have seen it on several F5000 etc race cars with blown oil coolers, scavenge oil can be harder on coolers than having the cooler on the pressure side. A way to fix this problem is a bypass valve before the cooler diverting the excess oil directly to the oil tank, or fit a thermostat so oil is diverted to either the oil tank or if on the pressure side to the main oil gallery without going through the cooler.

[vector1]

Originally Posted by Ant

When you start a dry sump engine there is potential for the oil cooler to fail due to a problem when the oil from the oil tank drains into the engine by gravity and the oil tank level can be high enough to cause a head, and on startup the scavenge sections suck an amount of cold oil from the oil pan and force it through the oil cooler, I have seen it on several F5000 etc race cars with blown oil coolers, scavenge oil can be harder on coolers than having the cooler on the pressure side. A way to fix this problem is a bypass valve before the cooler diverting the excess oil directly to the oil tank, or fit a thermostat so oil is diverted to either the oil tank or if on the pressure side to the main oil gallery without going through the cooler.

interesting, so it's the 3+ scavange sections putting an unbipassed solid wall of oil through the lines at excess pressure hitting the oil cooler that can kill it?