Oh b*ll*x

Do you mean to say I havent been waiting for my oil to warm up before putting my footdown.

I presumed once the temp gauge had reached 90 then it was fine to put my foot down... :(

I presumed once the temp gauge had reached 90 then it was fine to put my foot down... :(

So did I, but to be honest I'm not concerned...

I remember a couple (or ten) years ago being told by a guy who used to mechanic with a team racing RS Cosworths that one of the reasons for not wariming up an engine by letting it idle, was that by doing this you are not warming up the oil in the gearbox as quickly as you would do if driving the car. Their theory was that a warm (at normal 90'C) engine generates lower 'transmission' losses than a cold engine and you will be putting optimum power from the warm engine into a gearbox that is still cold - putting more strain on the gearbox internals.

Driving off in a cold engine/cold gearbox is supposedly more balanced than a warm engine/cold gearbox

Seems to make sense but I can't see the extra strain making that much diference myself.

horses for courses I suppose.

Personally I think it's better to have a clear windscreen and worn engine than a good engine embedded in a lampost?

Definitely agree with that - visibility means you live, whereas driving off without it means you may not be as lucky

As for caning the car and then letting it cool off a bit - good idea but really if you are driving motorway speeds over hilly environment and then get off the motorway, there isn't a great deal you can really do I do try and take it easy, change up earlier in town then outside so I suppose I kinda do that anyway.

As for waiting till the water temp hits 90 - the oil may not be on operating temperatures yet but it sure beats racing off when the water temp is still at the bottom of the range

For those with an inclination to Geekiness .....

Another snippet of information I picked up from work is that Water has a higher specific heat capacity than engine oil - that is the heat energy required to heat it up by one degree C is higher than that required to heat up oil by one degree C. The oil is actually quicker to heat up than the water!

...need a lie down now in a dark room ..too much thinking this week and its only tuesday.

The oil is actually quicker to heat up than the water!

Well, oil heats up quicker than water, yes - *however* in an engine they're not both used for the same tasks. Also, generally you want your oil to be hotter than your water...

Rob.

Well' date=' oil heats up quicker than water, yes - *however* in an engine they're not both used for the same tasks. Also, generally you want your oil to be hotter than your water...

Rob.[/quote']

Cor blimey now i am confused :confused:

I think I am going to carry on putting my foot down after the water is up to temp

Well, oil heats up quicker than water, yes - *however* in an engine they're not both used for the same tasks. Also, generally you want your oil to be hotter than your water...

This is true for cooking - but for cars? On my old Mk.1 Golf GTI, I fitted three gauges which included oil pressure and temperature. The working temperature for the oil was around 80-90 degrees while the water works as close to 100 degrees as it is allowed (in a pressurised system). On rare occasions, the oil would get to 100 or so, but then I would start to get worried.

On my old Mk.1 Golf GTI

...which, I'm guessing, didn't have a turbo. So the oil would run cooler?

Rob.

...which, I'm guessing, didn't have a turbo. So the oil would run cooler?

Right, no turbo. But, whether turbo or not, or oil cooler or not, one tries to achieve an optimum working temperature for the oil.

Right, no turbo. But, whether turbo or not, or oil cooler or not, one tries to achieve an optimum working temperature for the oil.

Which, when passing through a turbo which is about 500+Celsius, I doubt will be as low as 90!

Rob.

Which, when passing through a turbo which is about 500+Celsius, I doubt will be as low as 90!

:eek: I didn't realise that the oil passed through the turbo! In my old Golf days, turbos were an after though - just bolt-on and not plumbed in.

:eek: I didn't realise that the oil passed through the turbo! In my old Golf days, turbos were an after though - just bolt-on and not plumbed in.

Don't think so Mike, they always needed cooling & lubrication to their bearings, unless of course technological development is running backwards.

Nobody mentioned the catalytic converter! Historically, the idea was that you allowed the engine to warm up to allow the oil to thin and flow. Of course the downside to this is bore wash, where the rich mixture literally washes oil off the cylinder bores.

Modern oils have much better low temperature behaviour. So if you start and idle, you are really just wasting fuel and potentially wearing out your engine. Driving off, provided you do not cane it, will make the engine warm up in less time (using power gives more heat to the engines internals than idling).

The main reason for modern car manuals stating that you need to drive off immediately is that the catalytic converter is liable to damage and contamination until it has reached operating temperature. The flare control (startup) helps with the initial rush of exhaust gas through the cold catalyst, but you then need to drive the car in order to stick enough waste heat down the exhaust system to warm the cats. My automatic V6 Omega runs the car in first until the cats have warmed up!

Chris

Another point I was thinking about why leaving idle to warm up isn't the best plan. You could almost be "heatsoaking" a specific part of the engine and the other bits stay cool, giving a different temperature variation over the engine.

If you drive away calmly, you give all the parts of the engine (such as gearbox mentioned earlier) a chance to work and "swish the oil around the place". Could be entirely wrong though - wouldn't be the first time