Engine oil recommendations, please

[BigMike]

I'm going to do a mini-service in the next week or so.

Engine oil, air and oil filters and spark plugs.

Please can you make recommendations for oil to use.   (and the other bits, too)

'99 9-3 2.0T convertible.


Thanks for your help,

Mike

[sgould]

Saab spec for oil is fully synthetic 5w/30 to GM requirements.  The latest GM oil is called Dexos.

Cheapest I have found comes from Neo Brothers.   They also do a service kit with all the oil and the filters in it.

Mobil 1 is also OK.  In fact a lot of oil is good, but some descriptions on the can are misleading.  So take care.

A copy of the Saab spec is attached.  But it still shows a 0w/30.  It was later changed to 5w/30.  But the WIS has not been updated.

[BigMike]

Thank you - full and informed answer - much appreciated.

Regards,

Mike

[phoenix]

From an engine protection point of view, particularly when they have a few miles on, I prefer to use the slightly thicker 5W40.

Still fully synthetic of course and I now use Millers XFS. Available from Opie Oils or Camskill. Both also have the plugs.

I would also recommend using an engine flush.

[Audax]

I would also recommend using an engine flush.

Any particular reason why you'd use one? I've always told people not to bother as there's no real benefit.

[Max Headroom]

I would also recommend using an engine flush.

Any particular reason why you'd use one? I've always told people not to bother as there's no real benefit.

I know its a different kettle of fish but the prinicple is the same... At work I used to do a hot drain and flush on helicopter gearboxes. Hot because the oil is thinner and runs out quicker carrying any metallic particles with it, followed by a flush to get any remaining particles out.

On my cars however, I have done a similar thing but more to simply clean the remaining dirty old oil out rather than any metallic particles. Magnetic sump plugs are a must have

[phoenix]

To flush or not to flush... a topic of some debate for a long time.

As I see it the arguments against flushing are that it can loosen deposits which can then block the system. I can see that but on an engine that is properly maintained I reckon it helps do that little extra bit of cleaning before putting new oil in. It always goes in to a hot engine and I then allow it to idle for 10-15 mins.

[Audax]

I'm in the camp of why risk extra deposits (especially those that might block an oil strainer) or damaging engine seals and wonder what benefit there is of having the inside of the engine sparkly clean. I base much of this opinion on having seen the inside of many a Saab engine that has done a serious mileage and they all looked clean enough to me and that most (all?) engine manufacturers don't recommend flushes or using additives.

I must point out that I doubt that an engine flush is likely to actually cause harm to an engine (i.e. the risk of blocking a strainer or damaging seals is very low) but do think it's not worth the extra money spent. I would suggest that engine oil is always changed when warm (not hot!).

As for helicopter gearboxes, I'd leave that one to the experts 

[Max Headroom]

Heli gearboxes don't sludge up like car sumps tend to, do so my comparison wasn't entirely a fair one.

I can see the argument ofnot flushing - but in my mind, if something like those loose deposits are going to come off, I'd have thought they are more likely to come off from the heat and engine vibration frequencies of a running engine, than from flushing clean oil through a stationary engine... ie they're going to come off anyway whatever you do. 

[sgould]

My experience is of pipes that are bigger and colder.  But in general I would expect anything sticking to the side of a flowing pipe to reach a state of equilibrium.  How much sticks to the walls depends on three things.  Roughness of the walls.  Stickiness of the material and the speed of flow.

In a car engine, all three will be pretty consistent, so once the oil has stuck to the side, as it builds up the diameter will reduce.  Consequently the velocity will increase.  This will go on until the speed is too fast and the "sludge" can no longer stick.  A bit of a proviso that is it gets too sludged, the pressure relief  will open, but at some point equilibrium will be reached.

My view is that it is best left alone as the build up could be removed in chunks.  But, I would also support the use of flushing oil at each sevice, as long as it has been done from the beginning.

[Audax]

ie they're going to come off anyway whatever you do. 

In which case they'd get caught by the filter so you wouldn't need the engine flush