Oil hardening oil seals?

[Fyko]

I have been the owner of many Land Rover diesels. The diesel engine I favor is the 4-cylinder 2.5 Tdi. One major snag with this engine is its propensity to leak oil from the front and rear crankshaft seals. Replacement seals last me 10,000km and then they start to leak again. When the old seals are removed (they come built into their own bolt-on housing) they are harder than they should be and harder than when they were installed. One mechanic said they overheated, but that's impossible, my oil temps never exceed 70 C. Very vexing problem since the seals show no sign of actual wear.

A short while ago a zealous salesman persuaded me to change to motor oil sold under the name 'Delo Gold 15W 40' in this country. It comes from the local iteration of Chevron. Previously I have habitually used Castrol GTX Diesel in my engines, to the exclusion of everything else. Why? Dunno - its just a habit I acquired many years ago. Maybe from Castrol's race sponsorship, or some other advertisinng.

Anyway, within 1000km of changing to Delo Gold the crankshaft oil leaks dried up. I haven't removed the seals because that is major surgery on these engines, but I assume that something in the Delo has softened the seals. And something in the Castrol GTX had hardened them in the first place. Is such a thing possible? Has anyone ever seem this before?

Fyko. Cape Town, South Africa.

 

[Trav]

My guess is they are using an older seal material like NBR (Buna-N), they will harden fairly quickly unless the oil has some ester in the ad pack to keep them pliable, BMW had a problem with this seal material in the vanos system. The Delo oil probably has more ester and is keeping the seals soft.
When changing seals look to the aftermarket for upgraded seal materials like FKM.

 

[edwardh1]

are the seals you buy new from the dealer hard then at purchase?
in 1970 some parts I bought from Brit dealers looked like they were really old when sold to me, or bad material (i.e. cork when US people had switched over to other materials).

 

[Kuato]

Sounds like the Delo has solved your problem! I would stick with it.

 

[Fyko]

Many thanks for your input. The 2 crankshaftend- seals for the Tdi engine are not your standard format black oil seal of the type with a spring tightening the girth. They are made of some vortex-shaped brown colored material, specified by some nameless Brit, that is set into a casting that bolts onto the block. The seal part cannot be replaced independantlyy because it doesn't conform to any particular size. The youngest of these engines is now 16 years old and you can't get too fussy about where spare parts come from, you grab what you can get.

The purpose of this thread is twofold: One, I'm interested in what components of oil can affect rubber seals, and I'm learning about that here. The second is to let any Land Rover owners out there know that no, you don't have to go suicidal over those pesky oil leaks - just change to Delo if you've been using Castrol GTX(another British menace it seems).

As an added benefit the Delo actually raises oil pressure by a pound ot 2.

Thanks agaiin.
Fyko

 

[Fyko]

Thanks for the response.

In fact I have no idea about that. As I replied to another post, these engines went out of production in 1999. The ones I have date from the mid-nineties. In SA the LandRover agency is run by a bunch of bandits that price spare parts into the stratosphere so it is normal to use parts from pirate suppliers like Britpart.

We keep these engines going because thay are just so perfect for the application. The LandRover Defender Tdi happens to be superb vehicle for the purpose we put it to. Nothing else comes close. Sadly the makers bowed to all sorts of greenie pressures and replaced this engine with a very poor alternative in 2000 - a 5-cylinder common-rail bag of problems, and this was made even worse in the third version of the vehicle (now entirely discontinued).

Once you put pirate parts into your engine (and we have little choice out here) you become a hostage to that pirate. These seals are so unique in design that it is not possible to use standard-design oil seal even if one could be found that conforms to the specific dimensions.

Thanks again.

Fyko

 

[Fyko]

Originally Posted By: Trav
My guess is they are using an older seal material like NBR (Buna-N), they will harden fairly quickly unless the oil has some ester in the ad pack to keep them pliable, BMW had a problem with this seal material in the vanos system. The Delo oil probably has more ester and is keeping the seals soft.
When changing seals look to the aftermarket for upgraded seal materials like FKM.


Thanks to you and Wikipedia I now know what both those terms mean. Many thanks.

 

[BobFout]

Just as a help to others, the Delo you got from Caltex?

 

[Fyko]

Originally Posted By: BobFout
Just as a help to others, the Delo you got from Caltex?


Yes. Caltex in SA. I don't know how widespread the Caltex brand is in the world at large, nor how widely the Delo oil brand is used. Chevron, the owner of the refinery in Cape Town as well as the 1500-odd filling stations is said to be selling off their SA assets.

 

[Fyko]

Originally Posted By: Trav
My guess is they are using an older seal material like NBR (Buna-N), they will harden fairly quickly unless the oil has some ester in the ad pack to keep them pliable, BMW had a problem with this seal material in the vanos system. The Delo oil probably has more ester and is keeping the seals soft.
When changing seals look to the aftermarket for upgraded seal materials like FKM.


Another highly vexatious oil-leak problem with a Land Rover is the trnsfer box.

The Intermediate Shaft, a static shaft carrying the intermediate gears between the input and output shafts, is bolted through one face of the case and floats with 2 O-rings in a bore in the opposite face. Generally both of these O-rings will start to leak after a year or so of service.

Since neither O-ring moves other than to adjust for heat expansion they cannot be wearing out. There must be something in the SAE 90 gear oil that causes them to either shrink or harden. Workshops have taken to gumming up the shaft-end with compound to stop the oil leaking out even when it gets past the O-rings.

Is it possible for gear oil (of no particular brand since many have been used) to harden or shrink an O-ring? Is it then possible to add something to such gear oil to reverse this process?

I understand that 'esters' are some fatty component of oil but the definition of the compound is exceedingly broad.

Many thanks.

 

[SonofJoe]

The bulk of any oil (base oil + VII polymer) is usually completely neutral to seal elastomers. However there are a number of additives that go into oil that are less benign.

Ashless dispersants (typically a PIBSA reacted with a Polyamide) are the worst offenders. The active nitrogen sites have a nasty habit of 'sucking' fluorine atoms out of nitrile rubbers (also known as Viton rubber) and causing the rubber to harden and develop minute cracks. Oils containing a lot of ashless (typically diesel oils) are generally worse than ones than contain a less.

You can reduce the aggressiveness of a dispersant by 'capping'. This usually involves reacting the dispersant with some kind of acidic species such as Boric Acid (if you see Boron on a VOA, chances are this is where it's coming from). The dilemma for oil formulators however is that capped ashless dispersants are far less effective at doing their basic job (keeping the pistons clean and suspending soot/crud/nasties) than uncapped ones. No-one independantly rechecks the seal elastomer compatibility of commercial oils but if they did, I suspect there would be oils out there that were very marginal.

Ashless isn't the only additive that can cause seal problems. Carbamates at high concentrations and stuff which contains a lot of active sulphur will attack seals if left unconstrained.

Given your unique circumstances, I'd say avoid cheap, low specced oil (it's far more likely to contain uncapped ashless). Avoid any American PCMO. Use an oil that says it meets ACEA A3/B3 (in your case, it's actually preferable to A3/B4). Also look for something that's approved against any MB and VW spec number (VW seals are notoriously difficult to pass!).

 

[Popsy]

Why A3/B3 vs A3/B4?
Apart from the min TBN, what's the difference that isn't told?

 

[SonofJoe]

In theory, less ashless in A3/B3...

 

[neo3]

Originally Posted By: SonofJoe
T
Ashless dispersants (typically a PIBSA reacted with a Polyamide) are the worst offenders. The active nitrogen sites have a nasty habit of 'sucking' fluorine atoms out of nitrile rubbers (also known as Viton rubber) and causing the rubber to harden and develop minute cracks. Oils containing a lot of ashless (typically diesel oils) are generally worse than ones than contain a less.


So would this be a reason not to use a hdeo oil in a gas engine? I'm currently using Delo 5W40 synthetic, since there is no 5W40 PCMO I can easily find locally, and the Delo seems to be high quality from its list of approvals (and it's also rated SN).

 

[SonofJoe]

Originally Posted By: neo3
Originally Posted By: SonofJoe
T
Ashless dispersants (typically a PIBSA reacted with a Polyamide) are the worst offenders. The active nitrogen sites have a nasty habit of 'sucking' fluorine atoms out of nitrile rubbers (also known as Viton rubber) and causing the rubber to harden and develop minute cracks. Oils containing a lot of ashless (typically diesel oils) are generally worse than ones than contain a less.


So would this be a reason not to use a hdeo oil in a gas engine? I'm currently using Delo 5W40 synthetic, since there is no 5W40 PCMO I can easily find locally, and the Delo seems to be high quality from its list of approvals (and it's also rated SN).



It's like this...

In Europe, seal testing is the bane of every oil formulator's life! You have to test every elastomer, every which way, usually long before you ever get around to firing up engine tests. Which is odd in a way because until I read this post, I'd never ever seen oils creating seals problems in the field.

Back in the 1980's, VW kicked up a huge fuss about the compatibility of oils with seals. They claimed that engines of brand new cars were leaving puddles of oil on showroom floors. I've no way of knowing if they were telling the truth but I do sort of find this hard to believe because seals in compression (ie around the oil pan) are generally quite robust. It's only where they're in tension that cracking becomes an issue. A more suspicious person might think they were trying to deflect blame for some dodgy, badly fitting engineering but who's to say now.

Anyway, the upshot was that all Euro oils were henceforth forced to be seal friendly. That applied to both gasoline and diesel oils. If diesel oils contained more ashless for soot handling, then tough! The oil formulator just had to figure out how to square the circle. Interestingly at the time, and for a long time afterwards, US oils didn't have to pass ANY seal tests and cars didn't leak oil on showroom floors. Funny that!

So in short, my comments were somewhat directed to the OP with his dodgy Land Rover main seals. They might help him avoid this expensive repeating repair. However for most folks, I'd say you can use any oil on the market and not have to worry about seal compatibility because the American experience is that it's a non-problem.

 

[Fyko]

Originally Posted By: SonofJoe
The bulk of any oil (base oil + VII polymer) is usually completely neutral to seal elastomers. However there are a number of additives that go into oil that are less benign.

Given your unique circumstances, I'd say avoid cheap, low specced oil (it's far more likely to contain uncapped ashless). Avoid any American PCMO. Use an oil that says it meets ACEA A3/B3 (in your case, it's actually preferable to A3/B4). Also look for something that's approved against any MB and VW spec number (VW seals are notoriously difficult to pass!).



This is hugely fascinating for me (and sadly mostly way above my head). Could I trouble you for some expanded acronyms? My oil container tell me the SAE and API clssification, like SJ and CH-4.

I'm able to spend plenty of time researching any direction you point me in, though sometimes I miss a few days being in the field.

I really do appreciate the wisdom to be reaped on this forum - it's wonderful coming in contact with expertise on this level.If you could just dumb it down to my level it would help me a lot.

At this stage I've changed from Castrol GTX Diesel to Caltex (Chevron) Delo with good results from the crankshaft seals. I hope that Delo won't disappear from the shelves once Chevron sells their operation in SA. In Mozambique where I mostly operate Caltex/Chevron does not exist.

A remaining problem is with O-rings (they say they're Nitrile which harks back to NBR (Buna-N) from above) leaking gear oil. I've since taken it upon myself to add 10% of Wynns ATF Conditioner to the transfer box. This may upset a few purists out there being as this additive is advertised as being for ATF ( which I understand is 85% mineral oil with a substantial ad pack to remedy a wide range of conditions). Seeing as EP gear oil seems to contain a more limited ad pack I thought it could stand some more additives.

It's only a small oil leak from the transfer case but I don't like dribbling oil out in the eco-sensitive places that I work, and secondly there's only about 2 litres of oil in the tranfer box (I once ran one totally dry for hundreds of kilomtres before I traced that strange whining noise to a dry tranfer box. The box actually suffered no permanent damage and performed for another 20,000km before I had it overhauled).

Anyway I tried the Wynns stuff and I'll let you know if anything interesting happens. In the meantime I'd really like to understand what all those other A's and B's mean. Other than that it's really interesting to hear about oils fighting against seals and how different countries/governments face up to the issue.

I'll visit a VW workshop and find out what they do for their diesel engines.

The Land Rover main manual gearbox is another area of contention. The makers say to use ATF and since there is an oil pump at the end of one of the shafts I suppose there's no reason that should't work. But local workshops say the ATF doesn't resisit wear in the hot environment here, so they started using Castrol VMS, a synthetic gear oil. Until Castrol VMS was withdrawn from the market and is now only available in Australia. Castrol say the replacement for VMS is 80W-90 mineral gear oil, but the workshops don't agree, they say the mineral oil is too heavy for the oil pump to handle. Yet I'm told that SAE 90 gear oil has the same weight as SAE 40 engine oil - which no oil pump has any problem with. What to do? Don't change the main (R380) gearbox oil is what.

Are there any other fully synthetic gear oil?

Many thanks to all.

Fyko

 

[Fyko]

My edit time has elapsed so I can't edit the previous any more.

I am now up to sppeed on the ACEA standard. Also I found this http://www.oilspecifications.org/oiltool/oiltool.php conversion tool, which doesn't cover the brands I have available, but does give a general indication of what is equivalent to what.

Thanks again.

Fyko

 

[veryHeavy]

According to Warranty Direct's repair statistics, the Jaguar engines in Land Rovers are the top 10 in reliability, so I don't understand why you're having so much trouble. They rarely breakdown.

Maybe the diesel fuel is the problem (like with Mazda 6 diesels that keep leaking fuel into the cylinders).

At the end-of-the-day a car is an APPLIANCE. If your refrigerator or stove had bad seals that leaked cold or hot air, would you spent this much time worrying? (No you'd just deal with it until you bought a new frige or stove.) Ditto cars. Some cars are poorly designed, but they can be traded for a new appliance when the time arrives. (Eventually all cars end-up in the same place as all appliances you have ever owned: The junkyard.)