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Classic Motor oil - A warning (5 replies)

MGMiniman
7 months ago
MGMiniman 7 months ago

I have recently been in correspondence with Halfords technical regarding the Halfords 20w/50 Classic Motor Oil - in the green metal tin.

A few weeks ago in carrying out a change of an inner Drive joint on my Rover Mini Cooper I drained the oil and decided although the drained oil had not covered many miles to refill with fresh oil. I Visited the local Halfords and selected their own brand 20W/50 Classic Motor oil. This oil states on the tin that it is suitable for older classic engines.

On using the car I found that the previously correct oil pressure was reduced by some margin when hot. I checked the oil relief valve just in case of a piece of debris had got in there. No problem there. Clearly the change of the drive joint would have no effect on oil pressure so the only other change was the oil.  Decided to drain the Halfords oil and replaced it with the Mini Spares own brand 20W/50 oil. Bingo! Oil pressure restored to 60 psi hot running pressure 30-35 psi at tickover. Clearly then the hot viscosity of the Halfords product was the problem. Fortunately the car has an oil pressure gauge so I was aware of the problem, others with just the oil light would not be.

I flagged up this problem with Halfords customer technical service and they have responded that the Halfords Classic Oil may not be suitable for combined engine gearbox applications! How this affects oil pressure though beats me particularly as the car only covered a few dozen miles with this oil in the sump. It was claimed that that this grade of oil was not suitable for my Mainstream carb car but was OK for earlier models! If this oil is not suitable for my Rover Cooper then certainly it will not be suitable for the cars from the earlier production decades. The application description for the Halfords Classic oil does not mention any make and model but I have suggested that if there is doubt regarding specific applications this should be made clear on the tin.

This year I have owned, maintained, modified, restored and raced Minis in one form or another for 50 years, never having been without at least one in the garage. In all this time I have never had any problem with oil until now! Be warned!

 

MGMiniman

1970cooperd
7 months ago
1970cooperd 7 months ago

Thanks for the heads up MGMiniman. Any experiences are always welcome in my book. I'll be making a mental note! 

H97Basil
7 months ago
H97Basil 7 months ago

Hi.  As a fellow Rover mainstream carb Cooper owner I read this with interest.  My owner manual recommends 10W/30 or 10W/40 so is there a reason why you are on 20W/50?

Thanks

Island Blue
7 months ago
Island Blue 7 months ago

Interesting, I have been using the Halfords Classic oil or the Comma equivalent (which comes in a suspiciously similar tin) for several years.  No problems in the past but this year I used the Comma oil (with a picture of a Mini on the tin!) and although running pressure is perhaps a little lower, what I have definitely noticed since the change is that it takes longer for the pressure to come up when starting from cold.  Previously it was pretty much instant but not quite so now....

Funnily enough I did compare the various oils on offer including a Millers offering specially for the Mini and some of the specifications do vary.  I dismissed the difference as insignificant in the light of my previous experience and comparatively low annual mileage but I may do another change soon and see if that makes a difference.

Does anyone know who makes Mini Spares's oil?  

MGMiniman
7 months ago
MGMiniman 7 months ago

In response to Basil there really is no significant mechanical difference between a 60's 1275 S and a carb Mainstream so in this my 50th year of Mini ownership I have continued to use 20W/50 with no problem until now. I don't know why the other grades mentioned were recommended except perhaps at the oil Companies request!

I have heard from professional engine builders that the engines they have stripped using these grades have not fared so well. I have used 20W/50 in all capacities of Mini engines and in line A series motors as well. The interesting point is merely draining the oil and refilling with the Mini Spares offering restored the status quo with oil pressure.

The real differences for oil specifications occur on the introduction of the Spi and Mpi specification engine where I understand that some of the additives in the oil previously incorporated can potentially contaminate the exhaust catalytic converters.

In response to Island Blue, I understand the Halfords branded oil is supplied by Comma, hence the packaging similarity. The Mini Spares oil is Extol. I have realised that a while ago I changed the oil in my 1098cc Austin-Healey Sprite and have noticed a drop in hot oil pressure in that too, so I will try the Mini Spares 20W/50 in that too.

MGMiniman

MGMiniman
7 months ago
MGMiniman 7 months ago

Update. See this useful supplier with several products suitable for use in Mini engine gearbox units. https://www.classic-oils.net/Content/170/About-Oils

MGMiniman

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