Oil temperature during normal use
Discussion
Depends what oil you're running Thom. Generally, the lower the viscosity, the quicker it will warm up. It alsos depends on a lot of other things, like how old the engine is / how effective the oil pump is, how old the oil is, and so on.
Put it this way, the most damage you're going to do to your engine is start the thing in the morning. At that point, most of the oil is in the sump (unless you have dry sump lube). There is a second or two before the oil pump gets up to speed and starts doing its job.
Certainly on my Merc (yes, bloody Merc again - stick with me), when you cold start, there is about 2 seconds when you can hear the hydraulic tappets. Then they get their oil and silence reigns once again.
Hope this helps.
>> Edited by GregE240 on Tuesday 5th March 10:44
Put it this way, the most damage you're going to do to your engine is start the thing in the morning. At that point, most of the oil is in the sump (unless you have dry sump lube). There is a second or two before the oil pump gets up to speed and starts doing its job.
Certainly on my Merc (yes, bloody Merc again - stick with me), when you cold start, there is about 2 seconds when you can hear the hydraulic tappets. Then they get their oil and silence reigns once again.
Hope this helps.
>> Edited by GregE240 on Tuesday 5th March 10:44
If I remember from my 944S2 days, your car won't have an oil temp gauge, Thom, so it's guessing time (see post below). There are so many variables as Greg has mentioned, I'd just be sensible. Obviously don't rev it above 3-4k revs until coolant warm, then drive gently for a few more miles after that.
However, I believe that this topic can be overstated as many decent modern synthetic oils work well enough below peak operating temp to prevent any kind of barrel wear, even at high-ish revs. My worry would, perhaps, be things like making sure the oil is always above min and changed at least every 6k miles. These are far more important than waiting for ages after the coolant temp is normal. There can also be a danger of choosing oils that are far too thin for the application, say 0W30, as these have poor heat characteristics when the engine is warm and can be too thin for certain applications (like Turbo bearings). Sometimes, they can be so thin that you'll get blue smoke from the exhaust at high revs.
A decent 5W40 would be good in your car, or maybe go for a superb all rounder like Mobil 1 Motorsport 15W50.
However, I believe that this topic can be overstated as many decent modern synthetic oils work well enough below peak operating temp to prevent any kind of barrel wear, even at high-ish revs. My worry would, perhaps, be things like making sure the oil is always above min and changed at least every 6k miles. These are far more important than waiting for ages after the coolant temp is normal. There can also be a danger of choosing oils that are far too thin for the application, say 0W30, as these have poor heat characteristics when the engine is warm and can be too thin for certain applications (like Turbo bearings). Sometimes, they can be so thin that you'll get blue smoke from the exhaust at high revs.
A decent 5W40 would be good in your car, or maybe go for a superb all rounder like Mobil 1 Motorsport 15W50.
Greg,
Thank you for your reply.
My car runs on 00W40 oil, which is very low density.
The engine is in absolutely superb condition; an overall fuel consumption of 28-29 mpg (no matter how fast the car is driven!) shows the original owner had run it in extremely carefully (usually I am granted with comments such as : "are you still running it in?!", "is it new?", etc.
)
Therefore, my question takes account of a car which is in as-new condition (engine wise); actually I am used to covering something like 10-15 miles before revving above 3000rpm.
The oil is now 12,000 miles old, and I should be replacing it in the following weeks.
Anyway I haven't taken the wheel since January.I happen to go to the garage at least twice a month just to start it (bl**dy heavy studies= no time for anything
)
>> Edited by thom on Tuesday 5th March 11:52
Thank you for your reply.
My car runs on 00W40 oil, which is very low density.
The engine is in absolutely superb condition; an overall fuel consumption of 28-29 mpg (no matter how fast the car is driven!) shows the original owner had run it in extremely carefully (usually I am granted with comments such as : "are you still running it in?!", "is it new?", etc.
) Therefore, my question takes account of a car which is in as-new condition (engine wise); actually I am used to covering something like 10-15 miles before revving above 3000rpm.
The oil is now 12,000 miles old, and I should be replacing it in the following weeks.
Anyway I haven't taken the wheel since January.I happen to go to the garage at least twice a month just to start it (bl**dy heavy studies= no time for anything
) >> Edited by thom on Tuesday 5th March 11:52
quote:
Obviously don't rev it above 3-4k revs until coolant warm, then drive gently for a few more miles after that.
Yep mate, that was taken for granted when the car was bought
quote:
making sure the oil is always above min
No worries about that!
quote:
and changed at least every 6k miles.
Whoops!
quote:
There can also be a danger of choosing oils that are far too thin for the application, say 0W30, as these have poor heat characteristics when the engine is warm and can be too thin for certain applications (like Turbo bearings). Sometimes, they can be so thin that you'll get blue smoke from the exhaust at high revs.
The service book shows it has always been under Mobil 1 00W40
What actualy worries me is the white smoke from the exhaust when I start it up...but (luckily ?) disapppears after a while.
>> Edited by thom on Tuesday 5th March 11:43
quote:
What actualy worries me is the white smoke from the exhaust when I start it up...but (luckily ?) disapppears after a while.
Easy one this. When you switch off the engine the exhaust is hot. The moisture in the cold air condenses in the exhaust (plus a bit of exhaust vapour). When you start the engine, it heats this condensation up and presto ! White smoke from your exhaust.
0W/40 is a good oil, and in my experience there's not much to better Mobil 1. The only criticism I've ever heard people have of it is that in some applications its a little too thin - this can have quite damaging consequences (particularly on older engines where the tolerances aren't what they used to be - it can burn onto liners in the pistons and so on and spell the end of a healthy engine PDQ.
Domster says change every 6K - there's two schools of thought here. Mineral oil starts to break down a lot quicker than synthetic oil and therefore should be changed quicker. My father used to change oil every 3K - still does in his Bentley.
I think in the end you pays your money and takes your choice. Certainly you do no harm in draining earlier.
Thank you Domster, and Greg for the smoke thing;
about changing the oil, I just intend to respect what's written in the owner's manual: change every 12,000 miles.
Do you think that's reasonably often on a ten year old car?
(if matters: current oil consumption= 1 L / 1,200 miles)
>> Edited by thom on Tuesday 5th March 12:06
about changing the oil, I just intend to respect what's written in the owner's manual: change every 12,000 miles.
Do you think that's reasonably often on a ten year old car?
(if matters: current oil consumption= 1 L / 1,200 miles)
>> Edited by thom on Tuesday 5th March 12:06
Greg is spot on about the steam/white smoke. If you own a Lotus Carlton you convince yourself the head gasket has just disappeared through a turbo impeller. Steam on start up is not a problem.
The other reason 0W40 Mobil 1 isn't recommended for old engines, or ones that haven't been run on it before, is that the detergents in it can clean the bores so throughly that the engine will start to smoke badly.
With mineral oils 3k miles is fair enough, but Mobil 1 in a 'clean' engine like the S2's (my oil was always honey coloured!) could probably allow a 6k interval.
Leaving it to 12k may not do much damage, but I would still recommend a 6k oil, oil filter, plug/plug gap service. This is easy enough to do yourself for about 50 quid, or get a local garage to do it - doesn't need to appear on service book as not an official interval, but next owners (and you!) will eventually appreciate it.
The other reason 0W40 Mobil 1 isn't recommended for old engines, or ones that haven't been run on it before, is that the detergents in it can clean the bores so throughly that the engine will start to smoke badly.
With mineral oils 3k miles is fair enough, but Mobil 1 in a 'clean' engine like the S2's (my oil was always honey coloured!) could probably allow a 6k interval.
Leaving it to 12k may not do much damage, but I would still recommend a 6k oil, oil filter, plug/plug gap service. This is easy enough to do yourself for about 50 quid, or get a local garage to do it - doesn't need to appear on service book as not an official interval, but next owners (and you!) will eventually appreciate it.
quote:
but Mobil 1 in a 'clean' engine like the S2's (my oil was always honey coloured!)
Like mine now.
quote:
Leaving it to 12k may not do much damage
Phew!
quote:
This is easy enough to do yourself for about 50 quid, or get a local garage to do it - doesn't need to appear on service book as not an official interval, but next owners (and you!) will eventually appreciate it.
Yes I know this, I'm not completely 'new' in the business...
Anyway thank you for your help!
Gassing Station | Porsche General | Top of Page | What's New | My Stuff