External oil cooler for AW70-transmission in a 240?

[Vestman]

Howdy!

My ´85 240 with the AW70 automatic transmission might need an external oil cooler. I've heard that the one that's originally mounted on some 740's, fits the 240. Does anyone have more information on this, part#, pictures, guides...anything? There is virtually nothing about this on google.com.

TIA,
Lars Vestman, Denmark

 

[Stewart Hargrave]

From a point at sea, to the circles of your mind, this is Vestman:

Howdy!

My ´85 240 with the AW70 automatic transmission might need an external oil cooler. I've heard that the one that's originally mounted on some 740's, fits the 240. Does anyone have more information on this, part#, pictures, guides...anything? There is virtually nothing about this on google.com.

Why do you think you need one? Do you do a lot of towing, do you have overheating problems, or is it just time for a new radiator?

I've got an external oil cooler on my 740. I don't particularly need one, but the internal one apparently developed a leak (in fact it was a false alarm) and I happened to have one lying around. It's just an aftermarket oil cooler bought from an accessory shop, about 5 inches x 9 inches. It's connected by a couple of rubber hoses and screw cliped to the oil lines, and mounted in front of the radiator with zip-ties. I guess this is way over-specified, because the one in the radiator is only a small cylinder about 1.5 inches in dia. and 6 inches long.

Someone on here mentioned that it might lead to over-cooling in the winter, but so far I haven't noticed any problems. But maybe your Danish winters are colder than our British ones.

Given that a leak in the internal cooler could quickly lead to failure of the gearbox, I reckon on balance an external cooler is not a bad idea.

 

[Vestman]

"Stewart Hargrave":>

Why do you think you need one? Do you do a lot of towing, do you have overheating problems, or is it just time for a new radiator?

I have experienced that the tranny-oil have overheated twice (meduim brown colour), and that by medium quick highway driving after only about 40-70 miles. After that I changed the oil of course, but it happened again... I think the tranny is a bit sick or worn eventhough it has "only" 151k miles worth of wear. It also shifts a bit roughly between 2nd and 3rd when pushed a little. Oil level has always been correct.

I've got an external oil cooler on my 740. I don't particularly need one, but the internal one apparently developed a leak (in fact it was a false alarm) and I happened to have one lying around. It's just an aftermarket oil cooler bought from an accessory shop, about 5 inches x 9 inches. It's connected by a couple of rubber hoses and screw cliped to the oil lines, and mounted in front of the radiator with zip-ties. I guess this is way over-specified, because the one in the radiator is only a small cylinder about 1.5 inches in dia. and 6 inches long.

Yep, but I've changed the cooler between the incidents, so I reckon that the cooler is of no guilt what so ever.

Someone on here mentioned that it might lead to over-cooling in the winter, but so far I haven't noticed any problems. But maybe your Danish winters are colder than our British ones.

Oh well, it usually gets down to 5 or 10 degrees of frost. I don't think that will become an issue.

I just wanna extend the life of it instead of spending 2-300 £ too soon on an exchange unit.

Rgds,
Lars Vestman, Denmark

 

[djtcz]

snip<<

Why do you think you need one?
I guess this is way over-specified, because the one in the radiator is only a small cylinder about 1.5 inches in dia. and 6 inches long.

The difference in cooling apacity may be hard to judge based on physiscal size. Air cooling stuff requires about 100 X more air flow than cooling water flow, and much bigger surface areas too.

 

[Stewart Hargrave]

From a point at sea, to the circles of your mind, this is :

The difference in cooling apacity may be hard to judge based on physiscal size. Air cooling stuff requires about 100 X more air flow than cooling water flow, and much bigger surface areas too.

This is true, but don't forget that the temperature difference between oil and air is much greater than oil and water in a warmed up engine.