Can anyone tell me what the differential oil line running from the oil pump to the rear bumper and back to the cooler is actually for, is it for extra cooling or is it a buffer for extra oil, I mean the diff holds most of the oil and the cooler should be sufficient to cool the oil, I’ve tested the pump and it pumps like crazy so there should be enough flow.

Reason I’m asking most of the lines are rusted and I thought maybe it would be possible to use a small catch can/overflow can instead of this oil line.

Thanks Peter

Did you know the J spec cars don't have any cooler for the diff oil? I've had 2 of them and never had a problem with the diff.

To that end if your lines are corroding, I'd consider deleting the whole lot, simplifying the car a little more and saving a bit more weight. :)

I’ve been thinking about it after reading an earlier post just wondering what this oil line is for.

Thanks for the reply

Can anyone tell me what the differential oil line running from the oil pump to the rear bumper and back to the cooler is actually for, is it for extra cooling or is it a buffer for extra oil, I mean the diff holds most of the oil and the cooler should be sufficient to cool the oil, I’ve tested the pump and it pumps like crazy so there should be enough flow.

Reason I’m asking most of the lines are rusted and I thought maybe it would be possible to use a small catch can/overflow can instead of this oil line.

Thanks Peter

 

Nissan call that part (5) a "Tube differential oil cooler" and it is connected in series with the main cooler (24) and hot oil flows

through it and the main cooler. The system is included in Euro/UK spec cars as Nissan considered the potential for high speed

driving in Europe required additional cooling. Jspecs don't have the system and for the most part it is redundant unless you

drive at very high speeds (on track days for example).

 

 

For completeness, these are the FSM pages on the operation and electronics:

 

 

Edited April 24, 20187 yr by AndrewG
Added FSM pages

Thanks Andrew so it is an extra oil cooling have to think about replacing it or making it redundant now.

Thanks for the reply

That said, I toasted my diff on a wet track day at Ty Croes, I wasn't really giving it big drifts either, I now have 1 wheel drive a lot of the time :( Perhaps an oil cooler would have helped.

Just to clarify, having replaced plenty faulty / worn UK diffs ( with cooler ) and next to no jap diffs ( without cooler ) in the workshop then the cooler would seem to have no effect in real life use.

 

The pump is operated by a temperature sensor in the diff rear plate and is set so high its is highly unlikely to ever trigger the pump, Nissan clearly thought it was needed and then deliberately set it up never to operate, plain weird ?

 

Delete if leaking will be no issue at all.

 

Jeff

Just to clarify, having replaced plenty faulty / worn UK diffs ( with cooler ) and next to no jap diffs ( without cooler ) in the workshop then the cooler would seem to have no effect in real life use.

 

The pump is operated by a temperature sensor in the diff rear plate and is set so high its is highly unlikely to ever trigger the pump, Nissan clearly thought it was needed and then deliberately set it up never to operate, plain weird ?

 

Delete if leaking will be no issue at all.

 

Jeff

 

Sounds like great advice Jeff.