"there must be a method of oil priming because the engines were all new once"

Obviously there's a factory method but I think I read that the DIY method is to overfill the oil until the pump is submerged, turn the engine over to prime, then drain the excess.

John F mentioning a Mann W7058 filter made me check the price - around £7. My 1.0T Astra uses a W7056 and is around double the price. What can be so different? Perhaps the Peugeot one is cheaper because it's unable to catch small pieces of cambelt ;)

Edited by Chris M on 22/04/2023 at 16:02

Good job you didn't have Ford's 5 cyl Ranger, oil has to be replenished within 15 minutes because the oil pump can't self prime, no its not April !st this howler is absolutely genuine, first heard about it from John Cadogan,

Actually, IIRC, you first heard about it from me.

I first heard about it from John Cadogan, though his "take" was rather disapproving of people (like us) wingeing about it rather than the procedure itself.

He is, however, rather of the "new cars are inevitably in all respects better" school of...er...thought.

I would be worried about the oil being mucky, because, as described, it sounds like this muck is a sediment, which suggests its denjser than the bulk oil and in relatively large bits.

I don't know if belt-in-oil derived detritus would meet that description, but if I had one of these I'd be interested in finding out.

If you do a "blotter spot test" using laser printer paper, as the oil ages you get an additional dark ring on the chromatogram, which I assume is wear debris and/or coke.

I thought this might make an interesting student project, and did some preliminary fiddling about doing scans of digital photographs of chromatographs, and could detact various quantitative and qualitative changes during thermal decomposition of vegetable oil (as a model system )

That course was scrapped by the university, so I havn't been motivated to take it further. but I think the method has potential.

Edited by edlithgow on 23/04/2023 at 05:28

John

Could this be the same Puretech engine that eats timing belts which run in oil and disintegrate over time?

If so a local garage in Northampton always removes the sump to clear out all the remnants of the belt material not collected in the filter , just to make sure the bits don’t circulate once the new oil is filled . They carry out this procedure on every oil change .

Perhaps I overemphasized the dirtiness - it was no worse than other 10K mile oil changes I have done. Re the 'BIO' cambelt - I'm well aware of the history; the belt looks OK - the crumbling was sorted some years ago.

Its the words in your original post that worry me

A further 140mls of black crud came out. I then left it overnight, and in the morning there was another 20mls of grot

I have not seen anything like that come out of an engine in over 40 years that has had regular oil changes. In the 35 years I have owned Caterhams I have had 4 engines as I have upgraded them and taken off the sump I have never seen anything other than a small amount of residual oil that gets left behind after draining. Just remember that between 1988 and 2004 all those engines had twin 45 Weber carbs which whilst set up correctly were nowhere near as clean or efficient as the fuel injection used these days.

The first 2 litre Zetec I bought from a scrapyard (£150) had allegedly done 63,000 miles in its Mondeo home. When I took the cam cover off it looked beautiful, then removed the sump (without turning the engine over to ensure any crud did not get where it should not be) and it was way better than I expected after seeing many 1970's cross flow sumps.

With modern oils (synthetic or semi-synthetic) there should be no "crud or grot" after 20,000 miles.