Oil Types - Assistance Needed

rbrt

Long time reader...
Currently on my fourth car, and one thing my past two cars have had in common is a slight amount of oil consumption between services. I'm all for dipping to check my oil on a regular basis (first car and slight oil leak after gearbox change cemented that habit early!), but generally have no idea between the various types of oils as to what I should be putting into my engine.

Current car is a Saab 9-3 2.0 (2005), engine oil is fully synthetic, but can someone please explain the difference between 0W-30, 5W-40, 10W-30, etc and advise as to whether topping up by small amounts in between regular oil changes could be causing my engine any problems? Hopefully I'm not alone in the understanding of these oil types, my service manual doesn't use this format to describe what I should be putting in and on calling different Saab service departments I've been advised three different things (two different oil types as per above, the third said Saab-only oil in my particular engine...) :rolleyes:
www.castrol.com recommends 0W-30, still have the question of what happens when wrong oil is used

Reason I ask is lately my car seems to have a distinct smell eminating from the exhaust, not a dirty oil smell, and more than I would have noticed before. I've heard of oil sludge problems with Saabs before (not sure what the characteristics of this would be), and on recent inspection my oil seems to have become distinctly darker than previously despite being serviced circa 4K miles ago at which time the oil was clean. Will most likely drop it in for an oil change shortly, however any help on the above especially the oil types would be greatly appreciated.

Thanks,
Rbrt

Atlantic Dawn

Heres a guide http://www.carbibles.com/engineoil_bible.html.

Use whatever is recommended by the manufacturer, otherwise it's likely to be burned up by the engine.

I'd be concerned enough about the Saab to be honest, they are very vulnerable to a missed oil change, the sludge problem manifests to engine failure unfortunately. Full engine flush and dropping the sump and cleaning that is recommended. How dark is the oil ? Is it still golden or are we seeing black ?

Many folks recommend using diesel engine oil of the correct spec in engines prone to sludge, the only difference is extra detergents as diesels are filthy yokes internally, many people don't like the idea. The diesel engine oil will provide a slow, gentle cleaning though. A flush can be very harsh, as is evident if you read between the lines on the instructions for use.

rbrt

Thank you both for your replies.

Re the colour of the oil, it is golden towards the edges, and much darker than I would have normally seen at 5K miles (just checked) since last service.

On looking at my last service receipt, it quotes oil filter, sump washer, however only 1L of oil (10W40 btw), so really not too sure what's been done here, however the oil did look like it had been changed when dipping that evening and in the weeks shortly afterwards.

Back to your last point James, is an engine oil flush and sump cleaning something I could take on myself, I've changed oil in previous cars in the past, however for want of service history have let that be done with garages with this one?

Would a sludge issue result in greater engine noise also, I do a lot of motorway driving and whilst having switched from P-zero's to F1 Eagles recently, my paranoid self is now convincing myself that this could be down to an engine problem and not tyre noise? :-)

I don't know to be honest on a 9-3 (have never owned a Saab), depends on the car and what's in the way. It's not difficult technically, just need to torque it back up correctly with a new gasket. Is yours a 2.0 turbo ? I think it was the 2.0 turbo in the 9-5 that was known for going bang unexpectedly. Although I would imagine the engine is much of a muchness, it wasn't turbo related the probs they were know for. An engine flush is just lashing in a bottle of severe enough cleaners and other agents and let it idle for a few mins prior to draining it, I don't like the idea of engine flushes to be honest.

I'd be concerned enough if 'twas 10 40 they put on, a fully synthetic 10 40 is not a very common product.

rbrt

Yes, mine's the 2L Turbo, Aero model. I'll give same dealership a call on Monday to advise that the oil put into my car doesn't seem to match the recommendation and to confirm they haven't done anything they shouldn't have - will check and see what they charge for a flush and clean too. In the interim, I might visit a motor factors tomorrow with the mrs to see if I can pick up a Heynes manual, nothing else to be doing I suppose Thanks for all help

I would suggest that you sign up to a UK based Saab forum, they will tell you all you need to know

jimmyw

Have a gander through these threads on this site and you will see some usefull info there.

http://www.saabscene.com/forum/index.php?showtopic=31650071&hl=sludge+problem

http://www.saabscene.com/forum/index.php?act=Search&CODE=show&searchid=0d2fdb9bf8886db4f418e485fe5ccf5e&search_in=posts&result_type=topics&highlite=%2Bsludge

causes of the sludge issue
In 2005, it was announced that 1998-2003 B205 and B235 engines suffered from oil sludge-related failures. The failures are a result of a revised piston ring setup that was intended to reduce friction cause excessive blow-by into the crankcase as well as a new positive crankcase ventilation (PCV) system used on these models that was not capable of handling this excessive blow-by. Due to the poor crankcase ventilation, combustion by-products contaminate the oil, causing its additives to break down prematurely. Especially in the case of short trips, the engine oil does not reach full operating temperature for a sustained amount of time. When this occurs, these contaminates (mostly water, various unburned hydrocarbons, and acids formed by nitrogen oxides and sulfur oxides and water) aren't readily able to evaporate, making the situation even worse. Where the blow-by gases settle directly on the metal surfaces of the engine, a build up of "varnish" results.

The inadequate crankcase ventilation allows the PCV system components themselves to fall victim, as the poor ventilation of the blow-by gases allows them to condense into an acidic soup that attacks and dissolves the PCV hose rubber. This further compromises the effectiveness of the system and introduces fragments of hose rubber into the crankcase. Once the inadequately-vented combustion products have depleted the motor oil additives, the oil will start to oxidize rapidly and form a soft sludge material. The oxidized oil is also much more susceptible to thermal breakdown when circulating through the turbocharger. This breakdown leads to the formation of hard carbon particles, in a process known as turbo coking.

As a result, the aforementioned oxidation byproducts (soft sludge, harder carbon deposits, and hose rubber fragments) will then start to agglomerate. If not caught in time, the agglomerate can clog the extremely fine wire mesh at the end of the oil pump pickup tube, resulting in a loss of oil pressure. This resulted in several cases of rod bearing failure, premature turbocharger failure, as well as other lubrication-related failures. The sludge problems can be repaired under a special extended warranty for 8 years and unlimited miles. However, in order to take advantage of this warranty, SAAB requires their oil change intervals to be met and receipts presented to verify this

http://en.wikipedia.org/wiki/Saab_H_engine