Oil filter change in old car - how often?

[The Natural Philosopher]

Its when you pay full price and the thing blows up 1000 miles later...because the engine had done its 1000k without an oil change..

[Doctor Drivel]

Using a quality "fully" synthetic oil can mean the oil can last longer than the makers state. They specify intervals on low quality oils. But in diesels I would not chance it.

One automotive engineer, not mechanic, said the best thing is use the likes of Mobil 1 oil and a high quality oil filter that grabs particals of smaller microns. He said the engine will last and last and retain that newness feel for far longer.

[thirty-six]

Today's cars are less tolerant of under-pessure cooling systems and are reliant on anti-freeze to aid thermal transfer both in the engine and radiator. Annual coolant pressure and coolant checks should be peformed as a matter of course. Cambelt(s) should be checked as a matter of course (unless one is to adopt automatic replacement at 8 years/100,000miles) and it's probably also a good time to check oil pressure. Starter syatem checks should also be performed as a matter of course. Other systems/parts are generally mileage dependant or should be noticed and rectified by the driver as and when faults appear. Headlight bulb efficiency is possibly another check not fully covered in MOT testing which possibly should be included in an annual service. I think you are lucky to get good brightness levels much after 1000 hours of use.

Iron/copper electrode spark plugs still benefit from dressing every

3000 miles and the distributer rotor is still a better system than double ended coils or split tension systems. Unfortunately the rotor and cap do need attention each year due to erosion and corrosion and probable replacement at three years or 20,000 miles. It still gives a bigger bang, and that's what counts when doing your own servicing. It's an insignificant expense countered by improved engine efficiency and the high price of fuel.

[js.b1]

Actually since about 2004 Mobil 1 is no longer a true fully synthetic. Mobil lost a test case against Castrol re Magnatec which was claimed to be fully synthetic when it was in fact a hydrocracked Group IV mineral oil. The use of hydrocracking paraffin etc into engine oil makes a boost to profit from utilisation of lower grade stocks. As a result Mobil themselves moved to it, so basically synthetic can mean "true" polyolefin etc or blend of cracked mineral oils.

There is a true synthetic still available - Miller, however I think it is about =A365-69 for 4L. There comes a point when you are better off changing a cheaper oil more often due to water & fuel contamination and additive depletion. For a lot of stop-start driving your enemy is sludge, high end oils can tolerate this - but it can be better to just use a slightly lower oil and change often. Some cars have chronic problems with "mayonnaise" under the oil filler cap which grows with moisture contamination (poorly designed PCV system), others have problems with cam profile (think one VW) in which case you should use any particular oil they specify re additive packaged created for that OEM.

As for fine particles, you can use micro-fine bypass oil filters. In reality unless you are doing 35,000 miles per year the body of most cars is likely to suffer hidden corrosion in seams (rear wheel arch, hidden behind the front wheel arch tray) from about year 10 onwards and some much sooner. Many cars use bonded in wheel arches, there is no spot weld around the top part of the arch, the polyurethane bond is about 1cm higher up on the outer face; as soon as any corrosion takes place the lips are forced open and moisture can both penetrate and run around (classic wheel arch at the 9-o-clock & rear of rear sill corrosion on many cars). By 12yrs you have a real infestation and only know when it pops through from the inside-to-outside corrosion.

So balance maintenance with bodywork checks. If you buy new, apply dinitrol in the seams if you plan on keeping for the long term. Once corrosion has started little will stop it because car steel is so thin ironically at the most vulnerable places; typically 0.7mm in wheel arch areas and 0.8mm in bodywork, 1.0-1.2-(1.5mm) in stronger areas & frame rails. Corrosion thus perforates through first then runs along - hence the classic term "tin worm".

Well worth checking the various car forums for the "known faults & problem areas"; can save a fair amount re contingency, pre-emptive & avoidance.

[ARWadsworth]

Actually I do change the oil more often than 30K most times. My brother is my mechanic and if I was for example having new brake pads fitted and the oil has done 20K it makes sense for him to drop the oil whilst the car is on the ramps as it saves me losing another half a days work.

This year is the first time the oil light has come on when actually due for a change. Too many trips to London, Kent and the Lakes (I am blaming geoff for some of the London trips)

[thirty-six]

It was a few years ago, but I did get a good semi-synthetic from Vavolene. It was certainly better than the later Comma semi- synthetic. Currently using Halfords synthetic (bought in advance when on offer) but not overly impressed with its cold viscocity grading. Seems rather heavy on warm-up.

The Italian made basic filters P******* (I forgot) are supposedly good. I'm not so sure, perhaps it is the filter which is causing the loss in performance through warm-up. Come to think of it, I've not done a hot, full throttle acceleration test with this combination.

OOp's, it's a 5W40 and I wanted a 30 . How did that happen? That's an advantage of using synthetic, it's acceptable to use a lower viscocity which results in higher performance usually beyond the manufacturer's economy and speed/acceleration tests. At least in older motors which specified inferior oils.

I must check for this. Vehicle's over 10 years and has repaired front nearside three years ago, so ripe for rusting, I know manufacturers repair standards were not adhered to.

[dennis]

Cambelt(s) should be checked as a

There are a lot of cars out there that require cam belt replacement at

60,000 or even 40.000 miles so every 100,000 isn't a good idea.

[The Natural Philosopher]

Er no.

They can still end up with worn bores and buggered bearings and burn oil and then put a rod through the block.

[ARWadsworth]

Further to my other posts my van handbook says that "if more than 1 litre of oil is used for top ups between service intervals then the oil change interval is reduced to 20K and that the service interval display should be ignored"

[The Natural Philosopher]

Most belts do 60-80k

I've not seen one snap at 40k, but had two (both vauxhall) go at the sort of 70k mark.

[Dave Plowman (News)]

What sort of car are you talking about that still has a dizzy?

[Dave Plowman (News)]

Please name and shame so we know to avoid those makes.

[The Natural Philosopher]

most do. Or many do. No contacts but still one 25kv coil feeding one of four (6 or 8) plugs..via a rotating rotor arm. there may also be a sensor there to monitor crank position. But thats more generally on the camshaft

As is the distributor itself sometimes. Depends really on packaging.

[The Natural Philosopher]

Any car will do that if you abuse it with no oil and no filter cahnges drive it hard and let it go past a point of no return

Its LESS likely today because in general ignition timing and fuel mixture are far better controlled with EFI so chances of damaged valves pistons and general coking up are small. but enough shit in the oil, a blocked oil gallery and a run out bearing and clatter clatter bang as the big end goes..and there's a grand and a half for a new engine, or get a scrapper.

Or you get low coolant a warped head and a stressed overhead cam, that snaps and the piston and the valves have sex, discover theres no vagina, and proceed to make one..

Or the head gasket goes, dumps water in the oil, and that takes out the big ends - or even the mains..

There is a reason why you check oil, change filters and oil and change coolant on a regular basis....

[thirty-six]

Yes, Vauxhall have had engine assembly problems.

[thirty-six]

A reliable one.

[thirty-six]

It wasn't my fault, I didn't know the oil was four years old and loaded with petrol when I road-tested the van at 80mph. Yep, I'd just sorted out the ignition and carb and the beast was running well with top acceleration and hill climbing, so i took it on the dual carriageway. After probably 8 minutes of 80mph running, there was a change in engine note (muffled like) and I looked at the neelde and watched it dip slightly. "Ug, somethings wrong.". I eased off but the bad note remained so I declutched and the oil pressure light came on a couple of seconds before stalling so I let the clutch out for a bit to stop the engine seizing then coasted to a stop a couple of miles down the road. I phoned my brother, telling him what was wrong and to bring a new can of cheap thick oil so I could drive home. He arrived on his motorbike without the oil, so I drove at 25mph on the then cooled oil for the .12 mile or so home. The oil was black, stunk of petrol and had the consistency of water. It was a wonder I made it past two minutes at top speed. It had been a main bearing failure which dumped the oil pressure, and no you don't need to have used Slutt 50, a used engine will run at low loads without an oil feed for hours. There's a big difference in engine loading at 80mph than at

25mph-40mph (must have been the wind pushing ;-) ).

[thirty-six]

Must be using economy belts or there are other problems with design or assembly the manufacturer isn't being open about.

[Dave Plowman (News)]

Err, I wasn't suggesting neglecting routine servicing. Just querying the oft stated view that you need to change engine oil more often than the maker says.

And why just engine oil? Surely if there is some conspiracy to make engines fail early even when serviced by the book, it would also apply to every other part of the car which uses a lubricant?

[Dave Plowman (News)]

I ask again. Name one new car with any form of distributor. If one exists, avoid it. As it has an ancient engine design best left for the science museum.