3k oil changes, really ??

Dear old Routemaster buses had their oil sampled and checked for contaminants. If it was fine off they went again. Oil changes were often at 100,000 mile intervals. The engines never got cold which probably helped. When I was doing big mileages on my 99 (500+ miles a week) I changed my oil at 3,000 miles and it wasn't looking dirty at that point. Modern oils should last a long time between changes if you are using the bike frequently. Occasional short trips mean frequent oil changes.

Hi Hans,

My view is that if you have a MKIII with the filter then 5000 is ok.As regards some cars / busses doing high mileage, they probably have a larger quantity in the sump in the first place and they are water cooled so the temperatures are not so high.

My MkIII has 70,000 miles on it and it is still on standard bores and origonal big ends / mains. I put this down to the good air filter and good oil filter.

If I did not have a good oil filter I would probably change at 3k

Regards

Tony

I certainly agree that modern oils now generally allow longer service intervals on vehicles such as motorcars. But for my newish car the recommendation is still yearly or every 12,500 miles.

One of the issues that has to be considered here is the amount of moisture that can get into the system and then contaminate the oil. This is where a wet sump oil system has an advantage over the dry sumps and remote oil tanks of a Dominator and Commando. The cooling of the air in these oil tank can cause moisture rich air to be sucked inside. Evidence of this is often seen on the tank cap in the form of emusified gunge.

Modern oils, such as sythetics, tend to remain more anhydrous thereby retaining their properties for longer periods. This is good news in places such as forks and gearboxes which, if used in such, no longer really need a yearly change.

Another point worth considering is the oil filter if fitted. Again, most service manuals recommend a yearly renewal. In the 60s this was a must because otherwise the materials used in the construction of a filter were known to deteriorate. Does this still happen?

Lastly........ What about modern bikes? Many of these still have recommneded oil and filter changes at fairly low mileages.

I'm with Phil on this one, along with moisture, the other issue has to be contamination with piston ring blow by. Fitting a PCV has reduced the emulsion forming in my filler neck and, having the confidence in how much oil is actually in my engine before I ride it after fitting an anti drain down valve, means I can run less oil in the tank and get it up to cooking temperature. Particularly on short journeys. A full fastback oil tank and 250 miles last saturday didn't produce a particularly hot tank. Less oil is the answer in this case.

My thoughts are that oil is cheap- engine rebuilds are expensive.

Its probably better to have shorter intervals with cheaper oil than extended intervals with expensive oil

On my singles without air or oil filters I change the oil at less than 1k intervals.

On my Commando I change it at about 2k intervals.

I get no mayonase in my oil tanks and my engines seem to be lasting ok with plenty of compression.

The original Commando system of venting the crankcase via the oil tank does result in a lot of condensation and contamination in the tank and the system in general.

Every new Commando engine that I've dismantled has been filthy black inside but I change my oil at the 1000 mile mark and mine are as clean internally as the day they were assembled. I like it that way and will continue to do it, along with a yearly removal and cleaning of the oil tank.

An advantage of short intervals is also that examination of the filters will give an early warning of any problems.