Failed Oil Cooler?

[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?

[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?

[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.

[Baz]

Originally Posted by sjelby

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

Not quite Stan. All done on Unregistered Vehicle Permits, but hopefully full rego soon.

Baz

[boxhead]

Glad it is sorted Baz, One of failures can happen.

[Baz]

Originally Posted by boxhead

Glad it is sorted Baz, One of failures can happen.

Thanks Dave. I drove it home today from the workshop with the new cooler fitted and I was ever so pleased to hear NO STRANGE NOISES coming from the transmission. The 6L80E holds 9.7 litres and it took 5 litres to top it up. That's how much oil it pumped out in 100 metres.

Baz

[LoBelly]

Originally Posted by Baz

...The 6L80E holds 9.7 litres and it took 5 litres to top it up. That's how much oil it pumped out in 100 metres.

Baz

Good to know that the pump is functioning well

LB