Failed Oil Cooler?

[Baz]

Has anyone ever heard of the Oil Cooler located in the front of the body under the "Oval' opening failing? I would be interested in some input here.

I have utilised the Oil Cooler that most builders utilise for the engine, but in my car this Oil Cooler provides cooling for my 6L80E 6 speed Tiptronic Transmission. My concern here is:-
Would my transmission be cranking out more pressure to the Oil Cooler than the Oil Pump on an
LS2 6 litre GM engine which could in fact cause the Oil Cooler to fail?

Baz

[Aussie Mike]

Not sure about the oil pressures involved with an auto transmission but engine oil pressures can be up to 70psi. Combine that with cold sluggish oil and you can blow one apart.

With an engine oil thermostat setup it's good to put a one way check valve in the return line from the cooler. That way the thick cold oil under high pressure cant get pushed back towards the cooler. from the engine while the thermostat is shut.

Cheers

[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.

[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.

[Gav]

You don't have a blockage do you Baz?
What size lines are you using?

[Rick Parker]

Transmission Oil coolers are used in many OEM towing applications, go look at a few new vehicles and compare to what you are using and how they are plumbed.

If you are using a conventional oil cooler, be sure to mount it so the body is sandwiched and not located by the bottom or top end plates alone, Earls has in their catalog some examples of how to mount them, vibration will definately shorten their life dramatically.

[750hp]

Originally Posted by Baz

Would my transmission be cranking out more pressure to the Oil Cooler than the Oil Pump on an
LS2 6 litre

Baz

Baz, I can't say what your trans has, but my modified Powerglide auto has 240psi line pressure...

[Baz]

Originally Posted by 750hp

Baz, I can't say what your trans has, but my modified Powerglide auto has 240psi line pressure...

My 6L80E has the same maximum pressure at 250psi. The Derale Oil Coolers allegedly have been tested to 250 psi so everything should have been "cool".

Baz

[Gav]

That is line pressure Baz, not cooler pressure.
Line pressure is the operational pressure inside the box operating clutches ect.

[Baz]

Originally Posted by Gav

That is line pressure Baz, not cooler pressure.
Line pressure is the operational pressure inside the box operating clutches ect.

Copy that Gav. The Derale Oil Cooler is tested to 250 psi. I have researched the 6L80E.com website and there is no mention of pressures leaving the box. Me thinks that the only way I can establish the outgoing pressure from the transmission lines into the cooler would be to temporarily fit a gauge to the inlet side of the transmission line where it enters the cooler and actually measure the pressure this way. Any ideas on this proposal?

I know that there is a **** load of pressure created within the box. The first time I drove it, we failed to remove a yellow plastic plug from around the transmission breather pipe which is located on the upper rear portion of the box. After a few kilometres, the plug blew out with such force, that it dislodged the metal cradle which holds my sound system in place by around 6cms. The air release was similar to a truck dropping its air brakes.


Baz

[boxhead]

I would be making sure that the mounts are good and solid (vibration willkill the alloy cooler)
But taking a guess here, I would suggest the leak has initiated from somewhere close to one of the AN ends, and this has happened due to not using a second spanner to hold cooler part still (preventing from twisting) while tightening the hose.
I realise you said your builder did it up, but just because he is an "expert" at assembling kit cars, does not mean he may make a mistake.
I am a qualified mechanic, and i will put my hand up for doing some stupid things that I shouldnt have, we all can make a mistake.

Or has it been hit by a rock from the road?
A picture will help in diagnosis.

[Baz]

Originally Posted by boxhead

I would be making sure that the mounts are good and solid (vibration willkill the alloy cooler)
But taking a guess here, I would suggest the leak has initiated from somewhere close to one of the AN ends, and this has happened due to not using a second spanner to hold cooler part still (preventing from twisting) while tightening the hose.
I realise you said your builder did it up, but just because he is an "expert" at assembling kit cars, does not mean he may make a mistake.
I am a qualified mechanic, and i will put my hand up for doing some stupid things that I shouldnt have, we all can make a mistake.

Or has it been hit by a rock from the road?
A picture will help in diagnosis.

I think that the cause and results will be of interest to everyone on this forum, so I will advise in due course with supporting pics.


Baz

[Gav]

Naked dancing girls stuffed it Baz?

[Baz]

Verdict:- Oil Cooler had an internal failure. The core split between the 10th & 11th row. Derale investigating why failure occurred. Looks like Derale will be replacing the Oil Cooler under warranty, even though I purchased it 3 years ago. I suppose that's fair enough too as my Cobra has only done 1,200 k's. No pics as the fracture is internal.


Baz

[sjelby]

Hey Baz....
1200 k's ?????
Does this mean you have rego now?
Stan.