21 replies to this topic

[cal844]

I use comma classic (same as Halford stuff) changed once a year (upto 5k miles....)

Edited by cal844, 29 February 2024 - 07:36 PM.

[Steve220]

How do you gauge how good a filter is?

By its decomposition, filter element, seal quality, and the results for oil testing. Every oil change I send a sample off to the Oil lab https://www.theoillab.co.uk. costs around £45.

[mbolt998]

Given that I do not drive the mini much more than 3000k a year I tend to look at the oil and decide when to change it rather than a set km or time.
That being said does oil deteriorate over time rather than with mileage?
And having done a search on here I notice there is an old wives tale about the original mileage for oil change being 1500m. All the literature I have seen says 6000m so where did the 1500m figure come from?

My original owner's handbook for my 1979 1000 says to change the oil and filter every 6000 miles or 6 months. But idk if the 6 months thing is anything specific to oil: there are a whole bunch of things in the same list like lubricating the "accelerator control linkage, cable and pedal fulcrum". I haven't done that in 30 years. Does oil degrade with time? I don't know but I doubt it.

 

I don't know how much you can tell by looking at it. I would never leave it longer than 6k miles but wouldn't worry about time.

[IronmanG]

How do you gauge how good a filter is?

By its decomposition, filter element, seal quality, and the results for oil testing. Every oil change I send a sample off to the Oil lab https://www.theoillab.co.uk. costs around £45.

That's interesting. I think I do that on next oil change.

[Steve220]

How do you gauge how good a filter is?

By its decomposition, filter element, seal quality, and the results for oil testing. Every oil change I send a sample off to the Oil lab https://www.theoillab.co.uk. costs around £45.

That's interesting. I think I do that on next oil change.

I think its worth it. Shows how your engines fairing.

[Spider]

The Owners books up to at least 1979 all said the Oil Change Period is 3000 miles / 5000 km or 3 months, though in later years of that period, that was increased to 6 months.

Having said that, my own experience here is in terms of miles / km, I find that the factory suggestion here quite adequate. I know in later years those made in the UK, they did push this out to 6000 miles / 10000 km so that they'd have comparable service periods to other cars on the market at the time, and while that might be fine when they were new, certainly as they got miles under their belt, there'd be a price to pay for that. All the factory did, at least on the Metro, to gain this increase was to fit a larger oil filter, however, oil contamination, that would be picked up by the Oil filter, isn't the usual reason or need for an Oil change !!!!!!!!!!!! Granted, Oil technology has improved since the 60's but I don't rate it good enough to double the service limit.

The base component in 'Oil' isn't that good at lubricating. Additives are added to considerably improve that as well as giving the oil a working temperature range, which is even better again with multigrades. These additives deteriorate with age, for this reason, while not common knowledge, mineral based Oil has a shelf life. Here's what Penrite suggest;-

https://penriteoil.c...cating Oils.pdf

 

Oil in an engine also builds up acids as a by product of combustion and also from moisture, this is why there's a specified maximum time for it to be changed, apart from shelf life.

 

So, in answer to the original question here 'oil change frequency', if you are clocking up lots of miles then I'd suggest 3000 miles / 5000 km is fine, less if the weather's been hot for extended periods or the Mini / Moke is driven in dusty conditions.

If however it only does short runs or used less frequently, it's not an easy call. Short runs are a killer. As a ratio, the choke is on for longer periods putting more burnt and unburnt fuel in to the oil and also the engine temps don't climb high enough for long enough to properly dry out the oil. I've found it takes around 30 miles / 50 km as a minimum of driving (not idling in traffic !) to get the oil to this temperature, then it needs to be held there long enough to be effective and again, I've found that's around another 30 miles / 50 km. The type and condition of the Crankcase Ventilation system too plays a huge role here. If the crankcase is open vented or vented to a catch can, then you can easily double these numbers or more.

To put a number to it in some conditions, 6 months would be appropriate however I wouldn't go past 12 months.

[IronmanG]

I was going to leave mine until October. On the back of this I will change oil before it starts being used in anger next month