Thread: NSK bearing DU2 significance

I had a look through my NSK catalogue and could not find any reference to 2DU only a reference to the seal type. The DU seal type is limited to 11000 rpm for this size
(6303) due to heat build up from the contact seal(s) whereas the VV (black rubber) and ZZ (metal) non contact seals are rated at a maximum of 16000 rpm, exceeding these speeds continuously starts reduce the life of the bearing significantly.
Mm.

The 2 could possibly be nothing to do with the du, but rather a code for another feature.

I am really wondering just what the situation is now Metalman as yesterday I went to our local bearing supplier and was given the impression that DU2 was equivalent to the current DDU. As replacing this bearing required that the radiator be removed to extract the tensioner, I did not want to repeat the excercise anytime soon, so I asked if the DU2 code and the fact that the seals were red in colour indicated a higher temperature rating. I was told that it did not, but interestingly the replacement bearing, also an NSK brand, came in a box marked 6303DDUCM NS7S, but the bearing itself was marked 6303DU, which should indicate a single rubber seal, but the bearing was sealed both sides with a rubber seal. One could be mistaken for thinking that perhaps they had a shortage of the correct seals, and just used the physically equivalent seals marked for one sided sealed bearings.
The seal colour is more of a brown than the heritage red of the old seal, but from what you are saying Mm, the black seals of the VV seals would have had a higher temperature rating, so I'm not sure why these seals would have been used in preference to the others. The speed rating should be ok I think as engine speed only occasionally gets above 3000 RPM, and spends most of the time below 2500 RPM, so even with the tensioner being around 1/3 the size of the crank pulley, it is never going to spend much if any time doing 11000 RPM.
RC there is a feature designated by numeric indicators, and 2 indicates 1/4 full. Of what I'm not sure, grease is the most likely thing I can think of, but I may not have it right on that score either. The code list I have is in the link below.http://www.ahrinternational.com/NSK_nomenclature.shtml
Thanks for the input Mm and RC,
Rob

I did this job on my Patrol some years ago, can't remember what the bearing was, but I do remember having some trouble getting it.
The vehicle has done approx 150,000 km with the replacement with no problems.
As I recall it was not necessary to remove the radiator to do this job.
Mine is the 3.0l diesel by the way, may be different for other motors.

Hi Bradford, possibly not necessary to remove the radiator on my 4.2 turbo diesel either, but it does give you more room and generally make things easier. I'm glad I did remove the radiator as the aircon condenser was poorly fitted and was rubbing the bodywork, something I could not see with the radiator fitted. I am surprised that it had not rubbed a hole in it, but with some slight reshaping of the panel which frames the radiator and condenser problem fixed (I think, but the radiator is not yet re-fitted) As we are about to leave home for an extended trip, I was glad I found it. Also easier to see that alternator belt was looseish with no adjustment left, so fitted a shorter belt to fix that. In a workshop situation with a hoist and either special tools or modifies standard tools to get around "hard to access nuts or bolts", and if I was younger with less arthritis in my fingers, I don't think that radiator removal would have been necessary. My ute has done 270,000Km, so you probably have about 1/2 life left on your tensioner bearing. Cheers,
Rob.

Look after your 4.2 TD patrol guys. These motors are built well and have always had a cult following for their bulletproof longevity. Anyway, it appears that as time goes on and parts become even more scarce, these particular vehicles and parts are well sort after both here and in the middle east and this has created a spike in thefts of the 4.2L TD patrols. Apparently they strip the motors down and send them OS.

Sorry, bit OT but my mate is a mechanic and proud owner of a 4.2 TD GU patrol and informed me of this so thought I'd pass it on.

Simon

It can be confusing..... see here: http://www.ahrinternational.com/NSK_nomenclature.shtml

I would interpret this like this, but could be wrong:

Suffix DU means "single rubber contact seal"

(The more common suffix RS would mean "face riding rubber contact seal")

Suffix 2DU or 2RS would mean it has such seal on both sides

Suffix 2 after the seal type means it is filled to 1/4 volume with grease

Hi Chris, I think that you are mostly correct in your interpretation, and RC was also correct WRT the significance of the '2'. As I mentioned earlier NSK don't appear to be following their own rules in the case of the bearing I actually got rather than what was written on the box. For a memory refresher the box had 6303DDUCM, while the bearing had 6303DU. This should indicate a bearing with a single rubber contact seal, but the bearing was fitted with rubber contact seals on both sides.
Anyway the whole thing is back together now and the aircon has been recharged after a helium lock test. A few other issues were dealt with at the same time and hopefully Murphy has been cut off at the pass.
Thanks Simon for that info and I'll keep it in mind. If the overheating issues return I might leave the keys in it with the motor running, slab of beer on the seat, and all parked in the dodgiest part of town, with a few signs tacked to power poles advertising the fact. A note saying that I don't want to see it again in any sort of restorable condition would complete the picture
Thanks everyone for your input, it has been well appreciated,
Rob

Originally Posted by simonl

Look after your 4.2 TD patrol guys. These motors are built well and have always had a cult following for their bulletproof longevity. Anyway, it appears that as time goes on and parts become even more scarce, these particular vehicles and parts are well sort after both here and in the middle east and this has created a spike in thefts of the 4.2L TD patrols. Apparently they strip the motors down and send them OS.

Sorry, bit OT but my mate is a mechanic and proud owner of a 4.2 TD GU patrol and informed me of this so thought I'd pass it on.

Simon

I'm not sure what parts would be scarce, most of the parts are avalible new still. A mate of mine recently bought a new block for his GQ from Nissan.

Originally Posted by snapatap

I'm not sure what parts would be scarce, most of the parts are avalible new still. A mate of mine recently bought a new block for his GQ from Nissan.

A 3.0L or 4.2L block?

Simon

It was a 4.2L block Simon.