Mk III Stock Air Filter Element

During my edit of the Mk III Workshop Manual, I've come across a contradiction. Section E10 states that the stock foam air filter should be cleaned and oiled every 3,000 miles. Section K2 agrees with this. However, Section K3 makes no mention of cleaning at 3,000 miles. It states that the filter should be replaced at 6,000 miles. 6,000 miles is when the paper air filter element on earlier models is to be changed, according to Section K3 of the earlier manual. I suspect this is just a case of shoddy editing of the original Mk III manual. [I've certainly found lots of other mistakes] I installed the "ham can" air filter & 750 battery tray on my first Mk III, so I don't have any experience with the stock filter element. Can someone with experience, comment on how often they have/had to clean the air filter? How long do they last, before they need to be replaced?

Charlie

I clean it every 3000 and have replaced it twice in 30 years after it disintegrated.

I replaced the first one after 1,106 miles by burning it (& the airbox) in situ (not a process that I recommend), the replacement lasted +/- 38,000 miles & was cleaned when I 'remembered' that it 'needed to be done', to my shame not on a regular basis - I will do better with the new one, honest.

kommando said:

I clean it every 3000 and have replaced it twice in 30 years after it disintegrated.

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Thank you for verifying my suspicions. The manual also tells you to clean the filter element with gasoline [petrol] in Section E10. Does the filter actually last that long using gasoline? I would think that something like K&N air filter cleaner, or household cleaners like Fantastic or 409 would be safer.

Is 3,000 miles a reasonable cleaning interval? Or could you go longer between cleanings?

Mike Sullivan said:

I replaced the first one after 1,106 miles by burning it (& the airbox) in situ (not a process that I recommend), the replacement lasted +/- 38,000 miles & was cleaned when I 'remembered' that it 'needed to be done', to my shame not on a regular basis - I will do better with the new one, honest.

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Mike, Did the air box burn due to a back fire? Or was it a byproduct of cleaning the element with gasoline [petrol]? Perspiring minds want to know!

Hi Charlie, yes, it was a backfire - I didn't notice the effect - I was merrily driving along politely waving at people who were pointing & waving at me - I've posted the story somewhere else on here.

The element fitted was new (part of return to road fettling) & had been oiled with Castrol GTX, since then I have always cleaned my element with petrol before recoating with GTX. It's not happened since, but I have had smoke from the airbox after a backfire & I keep a fire extinguisher in the garage ;-)

I don't really see that using petrol should be a major issue, I don't drink it & garage is well ventilated With regards to it being a fire hazard, it evaporates quickly & to work efficiently the element is coated in oil (which is also a flame accelerant!) - others may of course disagree.

Cheers