
Originally Posted by
rick130
Old hands on here will be sick of hearing me mention this, but fifteen years ago I was able to extend the service intervals to 20,000km on the ex's GU Patrol with the TD42T.
This was back in the 500ppm sulphur diesel days, we lived on a farm, constant dirt road use and constant towing horses.
She was doing about 7,500-10,000km/month, I was over doing 5,000km oil changes every two to three weeks with premium mineral oils.
Oil analysis showed the HD premium syn oil could've gone longer easily, but we are in front financially, and wear metal numbers were lower than what we were getting at 5-7000km with the other oils we'd been using.
What I do have to mention is that nearly all trips were quite long, most were around five hours. The shortest trip undertaken would've been around 25km km. Short trips of under 30-40km are probably the hardest thing on a diesel, it takes that long to get things up to temp properly and vaporise of any condensation IMO.
The hardest thing of all is stop/start short trip city driving.
Oil change intervals need to be pulled back dramatically.
I can go into acidity, TBN, (the oils reserve alkalinity) etc if anyone is interested.
When I last saw that car about two years ago it was still gong strong at over 500,000km without a spanner on it.
The only thing I noticed was some oil getting past the valve stem seals when cold.
I'll also state again, the air filter is more important than the oil filter.
Full flow oil filters aren't terribly efficient, real filtration (around 1 micron) is only performed wth by-pass filters (think TD5 rotor filter)
The best synthetic media full flow oil filters are around beta2=6, (6 micron nominal) range, most cellulose fibre filters are in the 20-30 micron nominal range.
Most people change the air filter too frequently, air filters become more efficient as the filter loads, the downside is pressure drop increases.
The other thing to be careful when changing too frequently is introducing contamination by not being careful and clean when swapping them out.
One of the reasons why industrial/off road machines have safety filters inside the main filter.
The most important thing is the sealing in the air box, panel filters are shockers for not sealing properly, and don't be tempted into installing a washable type filter if you want to keep your car forever.
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