How long before engine oil is fully warm (petrol & diesel)?

How long before engine oil is fully warm (petrol & diesel)?

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Mound Dawg

1,915 posts

176 months

Sunday 12th November 2017
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kambites said:
Pica-Pica said:
Radiator cover?, many modern cars have flaps that close off the air flow to the rad during warm up
Why would you want to reduce air flow to the radiator during warm-up when there's no coolant flowing through the radiator until the thermostat opens anyway?

ETA: Ah you mean the oil cooler? Interesting point though, do cars with an oil-cooler not have a thermostat on the oil system? If not, why not?
You're right about the thermostat. I think that the blocking off the radiator was for aerodynamic reasons, I'm sure I remember seeing this in a Ford Focus ad. The difference must be negligible though.

My Alfa has an aftermarket cooler and I went for the thermostatic version when I fitted it because on a road car you won't need to cool the oil most of the time.

I would imagine that warm-up time varies between cars, the Alfa takes ages to warm its 5.5 litres of oil that sits in a big, finned aluminium sump, my Fiat on the other hand has 2.8 litres that runs through a nice hot turbo...

spookly

4,053 posts

97 months

Sunday 12th November 2017
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Pica-Pica said:
hajes said:
With switched off EGR it takes long time...everybody talks about EGR and there is many myths about EGR.

at 0deg C it takes about 30km to warm up engine oil and it stays around 80deg C...unless you have radiator cover for winter.

With dynamic EGR, which assists in engine warm-up process my Octavia HR I warms-up coolant in about 10km but engine oil stays about 50deg C at about 3deg C (recent reading...getting cold in mountains). So I guess, it will take an other 10km to warm-up engine oil as well.

It depends on car. Skoda uses coolant/oil heat exchanger...usually called "oil cooler". I think every VAG car since 2006 (or even older) uses this system. Modern cars have pre-heater or aux-heater already built in and one sit in warm car with 80deg C coolant.

I've improved cooling of my engine intensively due new engine calibration and my engine hardly keeps warm at sub 10deg C temperatures. I must use coolant radiator cover over winter.
Radiator cover?, many modern cars have flaps that close off the air flow to the rad during warm up
What's the point? The thermostat would be closed, so the radiator won't do anything anyway as no coolant would flow through it?? If air flow over the engine is decreased it might marginally improve warm up, but non air cooled engines aren't designed to shift heat from their surface hence the radiator.

Prinny

1,669 posts

101 months

Sunday 12th November 2017
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Interesting one for me this. My newly acquired M6 has the oil temperature gauge in place of the econometer, as did the previous z4.

The z4 would take around 3 miles of driving (normally) for the needle to move off the 70’ stop and start registering a value. Then, under load, it’d get to the 120’ centre mark & hover around it - i.e. sustained acceleration would take it to 130 or so.

The M6 takes about 3/4 of a mile to move off the 50’ stop, and is at the central 100’ in another half mile. It then doesn’t appear to move much under sustained load, at all.

Two questions therefore:

1 - does anyone know if these bmw oil gauges are ‘accurate’ - i.e. are they the same as the modern water temperature gauges that do cold > normal > hot, but don’t actually represent the ‘real’ value?
2 - I appreciate they’re two very different engines (n54 & s85), but based on the values, would you really expect a turbo engine to create 30’ extra heat?

Actually, there’s a 3rd question in here... My 760 runs at something like 103’ for the thermostat, there’s various documented efficiency reasons for this to be so. It’s a very high temperature however. I assume the same is true for the z4 engine. The M6’s thermostat is set at 79’. That’s a huge difference.

3 - I’m not especially comfortable (when I stop & think about it) to have a pressurised coolant system at > 100’ in the 760 (n73 engine for completeness). If there’s a lower temperature thermostat available, what would be the consequences of fitting?

(my expectations would be a slight increase in performance, and a slight decrease in economy - correct?). I’m just thinking that long term, >100’ pressurised coolant is not great for the rubbers in the system, so gaskets/tubing would cure prematurely & need replacing.

VeeFource

Original Poster:

1,076 posts

179 months

Monday 13th November 2017
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Prinny said:
Does anyone know if these bmw oil gauges are ‘accurate’ - i.e. are they the same as the modern water temperature gauges that do cold > normal > hot, but don’t actually represent the ‘real’ value?
I would question where the oil temperature gauge is on the system as having now fitted an oil temperature gauge to the sump plug of my car it takes about 5 miles before it even starts registering over 50°C and about 10 miles for it to be up to it's baseline running temperature of 80°C. My car is only a 1.6 four banger though so yours will probably warm up quicker to be fair.

Looking at the viscosity chart for the oil I use, there's not a lot in it over 70°C so I'll start to work the engine then but only fully stretch it once it's over 80°C as this is when it's virtually at it's thinnest.

A500leroy

5,197 posts

120 months

Sunday 5th May 2019
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id like to fit a pre heater to my daily, any suggestions?

DoubleD

22,154 posts

110 months

Sunday 5th May 2019
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A500leroy said:
id like to fit a pre heater to my daily, any suggestions?
Buy your wife a warm coat and get her to sit in the car until its warm.

VeeFource

Original Poster:

1,076 posts

179 months

Saturday 18th May 2019
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A500leroy said:
id like to fit a pre heater to my daily, any suggestions?
I've looked into these a bit. Seems the easiest and cheapest practical option is to fit a mains powered sump heater which is basically an adhesive backed pad at a cost of around £100. They look to help reduce warm up time a bit and probably some engine wear.

However there's the school of thought that most of the engine wear occurs in the first few seconds after startup due to their being a lack of oil rather than it being too cold and viscous. So not sure if it's worth the hassle/risk of problems/risk of driving off still plugged in. Also, the gearbox (and in some cases final drive boxes) oil will still be cold unless you put heaters on those as well.

spookly

4,053 posts

97 months

Saturday 18th May 2019
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VeeFource said:
I've looked into these a bit. Seems the easiest and cheapest practical option is to fit a mains powered sump heater which is basically an adhesive backed pad at a cost of around £100. They look to help reduce warm up time a bit and probably some engine wear.

However there's the school of thought that most of the engine wear occurs in the first few seconds after startup due to their being a lack of oil rather than it being too cold and viscous. So not sure if it's worth the hassle/risk of problems/risk of driving off still plugged in. Also, the gearbox (and in some cases final drive boxes) oil will still be cold unless you put heaters on those as well.
Given that most modern cars will easily crack 150k+ miles (and often many more) without the engine being opened, as long as they have regular oil changes, I'd say you are probably overthinking things.

Julian Thompson

2,557 posts

240 months

Saturday 18th May 2019
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The thing to consider is that there are all kinds of thermal gradients in the engine as it comes up to operating temperature. It’s not just a question of lubrication.


Alex_225

6,345 posts

203 months

Saturday 18th May 2019
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My CLS63 has an oil temp gauge which flashes the temp until it's up to speed (80 degrees I recall). The manual says to not use full acceleration until that point. I was genuinely surprised how quickly it got up to that temperature, maybe 10 minutes of running. I still give it a bit longer before using higher revs but I was surprised it was as quick as it was.

Julian Thompson

2,557 posts

240 months

Saturday 18th May 2019
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Part of it depends on the oil cooling strategy on the car. Some of them have “liquid to liquid” heat exchangers that run the oil past the water. This has the effect of warming the oil faster if there are no thermostatic controls present.

It really does depend on the car

Baldchap

7,803 posts

94 months

Saturday 18th May 2019
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I wait for the blue light to go out or the gauge to read warm.

The Tesla gets thrashed from ice cold!

Petrolsmasher

2,452 posts

118 months

Saturday 18th May 2019
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wow after reading this thread about how long people wait til opening up the taps i feel like i abuse my car.

In summer when its warm ill wait til 5 mins of driving as past then start to work it.

In winter usually more like 10 to 15 mins, but i never wait til ive driven 10 miles, jesus i would never have any fun if i did that!!

Condi

17,395 posts

173 months

Saturday 18th May 2019
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The Japanese used to pre-heat the oil in aircraft engines when launched from submarines. For obvious reasons running radial engines in an enclosed, air tight environment wasn't desirable, and neither was sitting on the surface while they warmed themselves up.

In a similar way, Russian front troops lit fires under their tanks to keep the engines warm, or simply didnt shut down their engines at all.

Exige77

6,519 posts

193 months

Saturday 18th May 2019
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The only way to really know is by having an oil temp gauge.

It does take a lot longer than people think to get oil temps up.

SimonTheSailor

12,638 posts

230 months

Saturday 18th May 2019
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TellYaWhatItIs said:
A petrol engine will always warm up quicker than a diesel engine.
Why don't we just stick with this easy answer..............that doesn't actually answer the original question.

Petrolsmasher

2,452 posts

118 months

Saturday 18th May 2019
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Exige77 said:
The only way to really know is by having an oil temp gauge.

It does take a lot longer than people think to get oil temps up.
But there isent much difference in oil viscosity between 30 and 90 degrees in a modern oil like 5w30 so does it matter much really?

Slushbox

1,484 posts

107 months

Sunday 19th May 2019
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Depends on the outside air temp, obviously. My 2.0 VW TDi takes 13 miles in winter at 5C for the oil temp to get to working temp of 85-90C. This at 50 mph on the dual carriageway. Car has automatic grille shutters which close to help the aero when the car doesn't need the blast cooling.

The coolant temp guage takes about 5 miles to get to its normal half-way mark. Car has oil temp in the central display.

Local city is five miles away. If I commuted to work in the winter, the oil would never get hot.

Spare tyre

9,754 posts

132 months

Sunday 19th May 2019
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Of course the time of year and how long the car is parked makes a big difference

VeeFource

Original Poster:

1,076 posts

179 months

Sunday 19th May 2019
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spookly said:
Given that most modern cars will easily crack 150k+ miles (and often many more) without the engine being opened, as long as they have regular oil changes, I'd say you are probably overthinking things.
True, but then how many horsepowers will they have lost by then? Up to a third if some of the episodes of Top Gear are to be believed and most of that will will be down to engine wear.

Baldchap said:
I wait for the blue light to go out or the gauge to read warm.

The Tesla gets thrashed from ice cold!
That just means your coolant is up to temperature. The oil takes over twice that time again to get up to 80°C based on my experience.

Also a friend of mine did a PHD in battery technology and says even they need warming up (ie using fairly gently at first) to prolong the life of the battery. Hard to say how long it would take to get a car battery pack warm mind.