[AMG KLR]

Hi all,

What is the proper protocol for warming up our B58s? IIRC the gauge in the dashboard (I have the 6WB Kombi) is for oil temp not coolant correct?

I actually got a P3 gauge hoping it would tell me oil temp but unfortunately it seems it is only coolant. I recall reading that coolant and oil temp do not correlate and I cannot trust the coolant temperature as an indicator for engine being ready for spirited driving

[Skyhigh]

That's right. The indicated temperature is oil temperature, which is much more relevant.

My own procedure:
- Extra careful, no pushing at all (relaxed, gentle driving) until the indicator gets out of the blue zone (happens relatively quickly, a few KMs, even in winter)
- Normal driving between blue and working temperature. Avoiding excessive RPMs.
- Heavy pushing, heavy launches, etc. not before the needle stabilises at optimal/max working temperature.

Procedure valid for any engine/vehicle. Just common sense.

P.s. what I also do with both my cars is to never start driving right after I turn the engine on. I always wait for the cold-start phase to be over, which is about 20-30 sec. This gives the oil enough time to circulate.

[IMS-340C]

I always raise the RPM to 2K for about a minute at idle after the cold start phase to make sure the oil reaches all engine parts and warms up as quickly as possible.

Makes sense to me.

[T_H_O_M_A_S]

i also net the cold start pass , then i take off in comfort and by testing i know it takes 5 to ten minutes depending on temp ambient before i go wot . no need to raise rpm for after cold start , oil pressure rises also when you take off normally

[IMS-340C]

Yeah mate but once you take off you are putting the weight of the car into the equation, IMO it's better to warm the engine freely.

Originally Posted by T_H_O_M_A_S

i also net the cold start pass , then i take off in comfort and by testing i know it takes 5 to ten minutes depending on temp ambient before i go wot . no need to raise rpm for after cold start , oil pressure rises also when you take off normally

[jackstrath]

Oil temp is nearly always behind water temp during heat up, so its defo better to have oil as a temp gauge if only 1 is avalible.

Reving the car to 2000rpm is a bit excessive, Ideally you want to keep the RPM as low as possible for the first 60 seconds of start up - but thats taking into account a few things. Thermial expansion, bearing pick up and lack of oil to lubricate.

Realistically the lack of oil to lubricate or the fear of not having all components getting oil once start up is minimal unless the engine has been shut down for a long time (id realistically say a week+) and even then i bet the parts will still have a fine coat of oil on them for it not to be a issue.

If your not getting oil pressure high enough to the point you feel the need to raise the RPM you might not be running the correct oil for you, but more than likely have another issue, Oil pressure with cold oil should always be good, and by thermo dynamics its going to be better than if the oil was hot at the same idle.

You want to keep the RPM as low as possible to gentally heat everything together at a same rate, pistions getting to hot fast run the real risk of picking up on your cylinder walls.

That all said this is a mass produced engine, not a hand built race engine, and tolerances will be as such away to reflect this. The thermostats are there to help heat the engine. Common sense really, take it easy untill up to temp and youll be good.

[IMS-340C]

I do leave the car idle the whole cold start period then I raise the RPM to 1500 for around 30 seconds and around another 30 seconds at 2000 RPM.

I think we all agree the aim is circulate and warm the oil as quickly as possible to all moving engine parts.

My common sense lead me to this and been doing it for the past 20 years hope I am not wrong, cheers mate

Originally Posted by jackstrath

Oil temp is nearly always behind water temp during heat up, so its defo better to have oil as a temp gauge if only 1 is avalible.

Reving the car to 2000rpm is a bit excessive, Ideally you want to keep the RPM as low as possible for the first 60 seconds of start up - but thats taking into account a few things. Thermial expansion, bearing pick up and lack of oil to lubricate.

Realistically the lack of oil to lubricate or the fear of not having all components getting oil once start up is minimal unless the engine has been shut down for a long time (id realistically say a week+) and even then i bet the parts will still have a fine coat of oil on them for it not to be a issue.

If your not getting oil pressure high enough to the point you feel the need to raise the RPM you might not be running the correct oil for you, but more than likely have another issue, Oil pressure with cold oil should always be good, and by thermo dynamics its going to be better than if the oil was hot at the same idle.

You want to keep the RPM as low as possible to gentally heat everything together at a same rate, pistions getting to hot fast run the real risk of picking up on your cylinder walls.

That all said this is a mass produced engine, not a hand built race engine, and tolerances will be as such away to reflect this. The thermostats are there to help heat the engine. Common sense really, take it easy untill up to temp and youll be good.

[kern417]

Originally Posted by IMS-340MP

Yeah mate but once you take off you are putting the weight of the car into the equation, IMO it's better to warm the engine freely.

absolutely not.


Driving your car and putting it under load is the most efficient way of warming up the engine. The entire purpose of the cold start sequence is to simulate driving the car by putting the engine under load. From an emissions perspective, letting your car sit and idle is less efficient and wastes more gas.

Also it doesn't take 30s for oil to circulate through the engine. Oil gets moving almost immediately.

Driving the car will warm it up the fastest so you spend the most time with your engine up at operating temperature. Turn it on and drive you car reasonably is the best practice.

[culpability]

I'm gonna kind of hi-jack this thread but it seems like a good place for it. I'm running bm3 on an otherwise stock car. Can I safely disable the cold start as long as I let the car sit for a few minutes to warm up or just drive it very lightly at first? I live on a cul-de-sac with a bunch of old neighbors and young children neighbors and the cold start with MPPSK is about enough to shake a glass of water in my own home and really don't wanna be bothering everyone else.
Surely I can get away with no cold start at least in the summer when its super hot?

[Skyhigh]

The so called "cold start" is there to heat up your cat converter faster and is an environmental measure only!

You can safely disable it, it will not affect your vehicle in any way, other than being less environmentally friendly (you'd be treating your neighbours with air- instead of noise- pollution )

[Wires]

Kern417 nailed it. If it took 30 seconds to get oil moving through the block, then rev'ing it at 2k just spun all your bearings.

OP, to "allow you to sleep at night" just wait until the oil gauge starts to move before really spirited driving.

[Skyhigh]

Originally Posted by Wires

OP, to "allow you to sleep at night" just wait until the oil gauge starts to move before really spirited driving.

^ That's definitely NOT enough!
Operational oil temperature starts from ~60 deg upwards!
There is a blue (cold) zone under the oil gauge needle for a reason…. That's the absolute minimum one should get out of first.

[Bdub440i]

Does nobody else wait until there temp gauge reads at least 180? That's what I've always done. No aggressive driving until then. Warms up better if you drive vs. idle.

[G.Newt]

FWIW, I would let my car idle 30-60 seconds, drive it slow out of the parking garage, then give it a good 3-5k rpm pull after exiting (not the best idea). This was about 2 years ago when I was commuting. Now I wfh so the car mostly sits until the weekends. I did an oil analysis in February: https://f30.bimmerpost.com/forums/sh...&postcount=106 and it came back great. Little to no bearing wear. I wouldn't stress too much about babying it. Just drive it light/normal after a letting it idle for 30 seconds (depending on ambient temps) and you should be good.

[IMS-340C]

Actually I only start moving when the needle start moving.

Originally Posted by Skyhigh

There is a blue (cold) zone under the oil gauge needle for a reason…. That's the absolute minimum one should get out of first.

[IMS-340C]

It's not just about circulating, oil temperature is as important .

As you know flooring an engine on a cold oil will eventually harm the engine.

At least it's not harmful to warm up the engine while the car is stationary.

Originally Posted by kern417

Also it doesn't take 30s for oil to circulate through the engine. Oil gets moving almost immediately.

Driving the car will warm it up the fastest so you spend the most time with your engine up at operating temperature. Turn it on and drive you car reasonably is the best practice.

[jackstrath]

Originally Posted by IMS-340MP

It's not just about circulating, oil temperature is as important .

As you know flooring an engine on a cold oil will eventually harm the engine.

At least it's not harmful to warm up the engine while the car is stationary.

Thats why you have oil for your climate and you really want to keep the W part (0W-30) relevent to where you live.

Oil starts protecting your motor from the second you turn it on. Its designed to, it "sticks" to all your bearing surfaces and leave a "protection film" over them. Flooring it when cold isnt the oil at fault for any damage, it certianlly wont help but the issue you will have the pistions heating and expanding far to fast and the block will not have expanded by that point and that when you risk pistion/ring/bore damage, 3 main things that oil being hot will have little effect on.
Example if you drained the oil and filled it with hot oil and turned the car on with everything else stone cold you will do damage to the engine.

I honestly was a bit meh when i seen this topic as i though people could apply a bit of common sense.....

Its simple, you wouldnt get out your bed and 60 seconds later go run a marathon as fast as you can, you get out of bed , take it easy and warm up and make your way to the point of starting the marathon. Apply the same logic to your car and youll be fine.

[IMS-340C]

That's exactly what I am doing mate I think you got me wrong mate.

After my stationary warm up procedure I drive very slowly until the oil needle is at the optimum position.

Originally Posted by jackstrath

Its simple, you wouldnt get out your bed and 60 seconds later go run a marathon as fast as you can, you get out of bed , take it easy and warm up and make your way to the point of starting the marathon. Apply the same logic to your car and youll be fine.

[kern417]

Originally Posted by IMS-340MP

It's not just about circulating, oil temperature is as important .

As you know flooring an engine on a cold oil will eventually harm the engine.

At least it's not harmful to warm up the engine while the car is stationary.

No matter what, free-revving your car is one of the worst things you can do. Especially when it's cold. Driving/cruising at 2k warms up the oil and is better for the engine than free revving the car. Holding RPMs up while parked will warm up the oil slower and does nothing to improve oil circulation. What you're doing is worse for the car than just driving it.

Originally Posted by G.Newt

FWIW, I would let my car idle 30-60 seconds, drive it slow out of the parking garage, then give it a good 3-5k rpm pull after exiting (not the best idea). This was about 2 years ago when I was commuting. Now I wfh so the car mostly sits until the weekends. I did an oil analysis in February: https://f30.bimmerpost.com/forums/sh...&postcount=106 and it came back great. Little to no bearing wear. I wouldn't stress too much about babying it. Just drive it light/normal after a letting it idle for 30 seconds (depending on ambient temps) and you should be good.

Absolutely. Ultimately we're car enthusiasts, so we enjoy arguing about what makes an engine last 300,000miles vs 310,000 miles. But the best practice is turn on your car, drive reasonably until it's up to temp, then floor it everywhere.

Or whatever you guys do to have a good time.

[IMS-340C]

Though I can't see why free revving the engine at low RPM 1500-2000 for a few seconds after the cold start period is harmful I do trust your opinion mate, cheers.

Originally Posted by kern417

No matter what, free-revving your car is one of the worst things you can do. Especially when it's cold. Driving/cruising at 2k warms up the oil and is better for the engine than free revving the car. Holding RPMs up while parked will warm up the oil slower and does nothing to improve oil circulation. What you're doing is worse for the car than just driving it.

[dmanb2b]

Originally Posted by IMS-340MP

Though I can't see why free revving the engine at low RPM 1500-2000 for a few seconds after the cold start period is harmful I do trust your opinion mate, cheers.

You have to realize that the climate you are in is very different from those in the more extreme northern and southern hemispheres. If some of us up north let the engine idle to warm up, we'd be sitting in our vehicles for 30+ minutes before driving waiting for oil that is up to operating temp.

The goal is always to get your oil up to operating temp as quickly and safely as possible. The best way to do that is to start the car and start driving it under a light load. Idling with no load only extends the warm-up period, prolongs the time your engine is running with oil that is not up to temp, and wastes fuel.

[G.Newt]

Originally Posted by kern417

No matter what, free-revving your car is one of the worst things you can do. Especially when it's cold. Driving/cruising at 2k warms up the oil and is better for the engine than free revving the car. Holding RPMs up while parked will warm up the oil slower and does nothing to improve oil circulation. What you're doing is worse for the car than just driving it.

Absolutely. Ultimately we're car enthusiasts, so we enjoy arguing about what makes an engine last 300,000miles vs 310,000 miles. But the best practice is turn on your car, drive reasonably until it's up to temp, then floor it everywhere.

Or whatever you guys do to have a good time.

Hell, in the CO winters, I'd be on the highway before the temp gauge even moved (those 15 degree mornings). In our 6-speeds, you know that's 2,700-3,000 rpm and that didn't harm the engine at all. These are modern engines y'all.

I use 0W-40 Castrol if anyone wondered.