Also quick. I was flipping through the manual and it states that you
should not let the car sit idle. Like when you warm it up. They also
say that as soon as you start the car drive it immediately, just keep
it slow until the temp gauge gets into the "normal" range. In this
winter I see a lot of people letting there cars run 10-15 min.
before driving them. Why aren't we supposed to let it sit idle?
Does this go for all newer cars? The only thing I could think of was that Carbon Monoxide would get into the car and they don't want that happening. Anybody else?
I know, what kind of guy reads the owners manual. Why not be a real man and take the engine out every night and bring it in the house with me so it stays warm. Right?
'87 928S4 5-spd w/ LSD
I think the biggest mistake many people make is to think that letting the engine warm up at tick over is somehow good for the engine. The oil pump in all the engines I have ever studied are of the positive displacement type so as the engine runs faster they pump more oil. The 928 is no exception to this.
When the engine is cold, the oil viscosity is higher and consequently is much more reluctant to flow. Couple this with low rpm's and the potential is clear. This is why much more wear and teat occurs during starting. for this reason I tend to blip the engine as soon as it fires up to get the oil moving around and pull off just as soon as I can. Over here in the Middle East it is not really a problem because of the ambient temperatures but back in England I always follow this regimen.
As Jim says, always keep the rpm's limited during initial warm up, say around 3000 rpm max and once the needle passes the 80C mark then engage warp drive. Never had an engine problem following this policy.
The other option is to use a pre-lube system like these accu sump systems.
Perhaps a bit extreme for normal road use but effective I would think.
Of course, if you live in a cold climatic region then during winter you should also use a low viscosity oil. For this reason I believe cars in Canada and presumably some of the colder regions of the States often have sump heaters to keep the oil warmish before you start the engine. Not sure if that was an option on 928's.
1990 S4 auto
I believe it is so the oil gets up to temp much quicker. When cold and first started, the oil is thicker. When driving, the engine achieves a higher rpm and the oil is more quickly circulated through the warming engine. This provides your engine with better lubrication during warm-up
If the car sits while just idling, the car doesn't warm up as quickly and the oil circulation is slower. Less protection against wear.
When cold, drive slowly until warm then, as Jim said, nail it! Yahoo. Well, unless there is ice on the ground. ;o) Let's not get sideways.
Just my thoughts,
Says exactly that in the Owner's Manual for '87 S4. "Do not let the engine
run on idle after cold start for more then a 1 or 2 mins" or words to that
effect. Also "don't race the engine until it reaches normal operating temp."
87 S4 AT Red/Black