Engine oil truth?

In article , snipped-for-privacy@no.spam.please spouted forth into uk.rec.cars.modifications...

What is the car? Someone on here may have owned one, and can give you sage advice about it.

Saab advice for dino oil is change every 3k with a filter change every second oil change.

For Synthetics on more modern Saabs it varies between 5-10k. As I've switched the 900 over to full synthetic I tend to still change it every 3k but use pretty much the cheapest 5w40 I can lay my hands on. Usually use Halfords 5w40, but the last few changes have been for Chevron 5w40 bought cheap at £10 for 4 litres. As the change interval is so short it doesn't really matter too much on an engine with 130k on it, and half of that life has been on full or semi synth, especially as I always give it 30 seconds idle down after I have been running slowly at the end of a journey, or 2 minutes idle down directly after a fast run..

Every 3K here, normaly run on Royal Purple Fully Synth, which is a little pricey.

Your call mate but it won't be doing it anygood running for 10 - 20K on the same oil. Every 5K at a push I'd say if its driven hard.

Matt

I'd be vary wary of running a car of that kind of age / mileage on a thin fully synthetic oil. I tried running the old 33 16v on semi-synthetic Selenia (very, very, expensive and incredibly 'thin'), but found it just pissed past the rings and made it smoke like a bastard.

Went back to, ISTR, 10w40 Castrol after that.

Then it was shagged! The oil is not the problem.

What's the car? 3000 miles is quite reasonable for an oil change, it's not to do with the oil "wearing out" so much as the oil "carrying away contaminants" which may be being introduced due to the engine, or the modifications.

Apparently >Hi,

Not at all, it's a pretty common problem with older engines (bear in mind the 33 engine went back to the early 70s before these ultra 'thin' oils were available) - it had also done 80k miles (not a lot, but enough) - which meant that there was a little wear to contend with, too.

And, not surprisingly, going back to a more conventional oil sorted my problem.

Alfas tend to burn oil anyway - so it's not unknown for Selinia to produce the above problem.

Synthetics are available in all kinds of grades, so thin means little.

A 5/70 synthetic oil for ex, is actually more even or consistent than a "20/50" oil... Both will be around the same at "normal" temps, but at low temps (cold winter frosty starts) the synthetic is thinner than the old style oil. Both are still way TOO thick!

At say 120 degrees, the "thicker" 20/50 is now way THINNER! than the synthetic is....

So it depends on what you choose and why.

Is that how long they last or how often you change the oil ;)?

Even my Ka gets oil changes every 5k. 10 and 20k is just trying to sell the cars to fleet buyers looking for low servicing costs IMO.

No need for fully synthetic - just use a good quality branded semi-synth, to the spec it says in the handbook - Magnatec is pretty good 10/40 for example.

Change it twice as often as the schedule says - so every 5,000 miles in your case - should cost

No, it just had high mileage.

Steve is right. High-mileage engines don't usually react well if you swap to 0/40 (or similar) - it's so thin, it seeps past the seals, and gets to places it shouldn't.

No he's right. There is an issue with some of the older engines with oil leaking past the crank seals on older Saab engines with higher mileage when switching to fully synth oil.

Although nobody seems to be able to say what mileage is high for a Saab engine. As the longest running unrebuilt road driven on is approaching a million miles, with many between 350 and 500,000, those are those I consider high mileage.

A lot of owners who had weaping probs with the crank seals switched back to semi synth instead of going back to 10w30 mineral and all the leaking stopped, but minimal coking of the oil. The official line from Saab is to use Saab Turboi oil. Saab Turbo oil used to be semi-synth and now I believe is Mobil 1 (0w40).

I've found that I tend to use between 1/2 and 1 litre of oil top ups in the 3 three months between changes (normally closer to 1/2 though).

I can't beleive it specifies 5/40 in the handbook ? Thin oil in a turbo car isn't a good idea - the seals in the turbo itself aren't particularly tight ! I think you'd be better off with 10/40, unless SAABs have some particular wierdness ?

That applies to most cars !

High mileage likes thicker oil.

Saab NA engines use 10w30 dino oil. Saab Turbo oil is rebranded 0w40 Mobil 1. Used to be a semi synth of some kind, but don't know what brand. Locally all that is available is

It takes me the same time as it does the garage, minus the 40 minutes travel to and from the garage, saves me £15 (which can be more usefully spent on booze and creme eggs), can be done when convenient to me, and the oily hands are remedied by application of soap and water. You'd be mad to take it to a garage :-)

Fair enough if your garage is miles away - clearly you're not gonna go there unless you have to ! Mine is about 1 minutes walk.

How can you save £15 ??

Garage changes my 10/40 oil, and filter, for £27.

It would therefore cost me £1 *MORE* to do it myself !

Last time I got mine done, was "while I waited" on a Saturday morning.

Err, so it WAS shagged then...

Because the engines are worn! If you took one apart and measured it up, it would be worn beyond service limits. Shagged!

hmmm.. I change my Ti oil every 6k and stick to the 10w40 it recommends in the manual.. never quite understood what the practical difference between synthetic/part-synthetic is? How often do you change yout Ti oil?

Bigus