Warm up time for 0w vs 5w or 10w

[dakota99]

I usually let my truck idle until the water temp is 70-80F, then take off and drive easy. I wish i had an electric fan though, the clutch fan wont release when cold until you drive like five blocks. Even at 1,300 - 1,500 rpm it sounds like you're beating the [censored] out of the engine it's so loud. According to my scangauge the engine goes from open to closed loop right around 80F water temp.

Oh and can't forget, the people that inevitably get behind you after you leave, even when you pick the least traveled route. Freaking out because you're going the speed limit..

 

[hooligan24]

Originally Posted By: Samilcar
Originally Posted By: CATERHAM
Originally Posted By: Samilcar
Originally Posted By: s7er
Shouldn't it be something like:
wait for a while in idle oil will heat and viscosity decreases(which is good - perfect oil viscosity around 10 cSt at 100c)

The problem with this is that it would take hours of idling to even approach the normal 100°C (10 cSt) oil temperature from a cold start.

Lets not exagerate here.
An idling engine will get the oil up to normal operating temp's in about the same time as driving slowly


I'm not so sure about that, but I have nothing to back me up data-wise. The only way to know for sure would be to monitor the rise in actual oil temperature over time under the two different conditions. I do know that the rise in oil temperature lags well behind the rise in coolant temperature as indicated by the few times I've driven vehicles that have both coolant and oil temperature gauges.

Does anyone here have any experience with monitoring oil temp rises under the two different conditions?



in my neon it takes about 11-12 miles of highway(50 mph with a couple of possible lights) driving to get the oil from 40f to 195f. While working on the car the other day and running it to keep warm inside while doing the work, it took about 25 minutes to reach 180f, and another 10-12 minutes to get to 195f. The car has a 195 degree thermostat and a oil/coolant heat exchanger to help cool/heat the oil

 

[rjacket]

Yeah I saw a test that someone did on their Geo in minus f temps and they found their engine temperature dropped when stopped at lights and that it took 17 minutes of idling to get the oil to any sort of driving temperature.

Paradoxically, it seems that the colder it is, the worse an idea idling is to warm the oil.

Here is the test I read:

Cold start test

 

[rjacket]

Originally Posted By: cp3
I'm sure it would be but I think the power requirement for the heater would probably be too much for the battery. There are oil pan heaters that plug in and could be connected to a timer.


Maybe a hybrid could handle it?

 

[Garak]

Originally Posted By: CATERHAM
In the past I have started engines in the dead of winter in the garage, left them idling and after 15-20 minutes the oil temp's are more or less where they would be after a 15-20 slow run on the road.


Same basic experience in my Audi. The only way I got the oil warming faster was if I was hitting the highway right away. Then, I'd keep to a conservative 55 mph until the temperature had appropriately risen.

Just puttering around town in the winter made little difference from straight idling.

 

[Gokhan]

Originally Posted By: CATERHAM
Thick oil will increase engine wear at higher rev's. The point is you don't know at what point that will occur.
Keeping the rev's down during the warming up process will obviously minimize the increased wear.
That's one of the advantages of having an oil pressure gauge.
You'll know how high you can rev the engine without the oil pump going into by pass mode. And even with a high VI 0W-20 oil you won't be able to use maximum rev's until the oil temp's are at least up to 70C and avoid going into by-pass and that can take a very long time, long after the coolant temp's have reached normal operating temp's if at all in very cold conditions.
But the lighter the oil and the higher the oil's VI the better as it will provides more of a safety margin from potential cavitation and increased wear during the warming up process.

By cavitation, do you mean that the oil flow not being able keep up with the RPM and air gaps forming as a result? I don't know if this can actually happen. Do you mean that somehow opening of the relief valve on the oil pump causes cavitation? Why do you think that the best oil pressure is the pressure at which the relief valve opens? Do you have any reference on this and cavitation?

 

[mechtech2]

Cavitation - cave - tooth cavity -a hole -etc

This is not a problem except for a very few individual engines.
Also, water pumps and other fluid pumps can have a cavitation problem.

Q RJ -'Yeah I saw a test that someone did on their Geo in minus f temps and they found their engine temperature dropped when stopped at lights and that it took 17 minutes of idling to get the oil to any sort of driving temperature."
This is how it is.

 

[CATERHAM]

Originally Posted By: Gokhan
Originally Posted By: CATERHAM
Thick oil will increase engine wear at higher rev's. The point is you don't know at what point that will occur.
Keeping the rev's down during the warming up process will obviously minimize the increased wear.
That's one of the advantages of having an oil pressure gauge.
You'll know how high you can rev the engine without the oil pump going into by pass mode. And even with a high VI 0W-20 oil you won't be able to use maximum rev's until the oil temp's are at least up to 70C and avoid going into by-pass and that can take a very long time, long after the coolant temp's have reached normal operating temp's if at all in very cold conditions.
But the lighter the oil and the higher the oil's VI the better as it will provides more of a safety margin from potential cavitation and increased wear during the warming up process.

By cavitation, do you mean that the oil flow not being able keep up with the RPM and air gaps forming as a result? I don't know if this can actually happen. Do you mean that somehow opening of the relief valve on the oil pump causes cavitation? Why do you think that the best oil pressure is the pressure at which the relief valve opens? Do you have any reference on this and cavitation?

Cavitation can occur in any auto part but usually only becomes an issue in high reving engines that unfortunately spec' very heavy oil such as low VI 40wt, 50wt and the 10W-60 grade. Many high performance engines are ruined by owners that red line their engines even at temp's as high as room temperature. Even just blipping the throttle in a stone cold engine can do it. Rings and bearings are among the sensitive engine areas. Large chunks of metal can break off and a used oil analysis may not detect this. Cutting open the oil filter will of course and is a good practice.

The "best oil pressure" is not just before the oil pump by-pass point, it's well below that. But one should not rev' an engine in by-pass mode. I use my oil pressure gauge which indicates the by-pass point as a sort of variable redline during the warming up process; it's a good discipline to follow, particularly at the track when you are anxious to get "on it" and may be running a heavy oil.
It's the reason the M series BMWs that spec' 10W-60 have a variable redline.