Factors that can affect warming up time

Originally Posted by AEHaas
Most sensors measure water temperature and it warms up within minutes of starting the engine. That is why you can get heat for defrosting and for the interior in winter. AEHaas

That brings up another question. Newer vehicles get heat out of the vents much quicker than many of the older cars did. Even on the coldest of mornings. On both my 2015 Jeep, and 2018 Toyota, I will have noticeable heat coming out of the vents, within just a couple of minutes of starting a dead cold engine. Usually as soon as the engine drops out of high idle, and I back out, I can feel the heat.

Back in the 70's, it seemed you had to drive much longer and further before you started to get any heat. What did they change to accomplish this? The newer vehicles seem to produce noticeable heat long before the temperature gauge even moves.

Where on the older one's you would see the temperature gauge move well off "Cold", before you got ANY heat out of them. And I'm talking about when they were new. Not after 70,000 miles with a neglected cooling system, and a clogged up heater core.
 
Originally Posted by Srt20
Does the MB have exhaust manifold cooling? My guess is it does. Thats why your coolant warms up much faster vs the other. My 2.0T has coolant running through the exhaust manifold and it warms faster than any vehicle Ive ever owned or even driven.

Do you know if any non turbo engines have exhaust manifold cooling? Neither my Jeep or Toyota have turbos, and as I mentioned in my above post, they both produce heat unbelievably quickly from a dead cold start. (5.7 HEMI V-8 & 2.5 4-Cylinder).
 
Originally Posted by LvR
Quality of the radiator bypass system during warmup
Quality and design of thermostat (read old mechanical with possibly bleed through hole constantly circulating through the radiator vs total shut-off ability of modern electronic thermostats)
Volume and type of block/head material to be heated
Volume and type of coolant
IMO oil will have close to zero effect on achieving normal operating temperature of the engine


I'm with you 100%
 
Originally Posted by Shannow
Originally Posted by Mad_Hatter

I could be wrong here but I don't think changing the viscosity is going to have a dramatic effect on how fast your engine reaches operating temp. Since oil actually acts like a coolant, no matter what viscosity you run it will do the exact opposite (cool v. heat) of what you're trying to achieve.


No, you are wrong here...

The oil between the bearing surfaces carrries away heat, buit's heat that's generatedin the oilfilm itself...thicker,cooler oil,more RPMmeansmore heat,and faster warmup.

For starters I didn't say it (running a thicker oil) wouldn't have ANY effect, i said it wouldn't have a dramatic effect but maybe I'm wrong. What amount of time savings are you suggesting??..5, 10, 25%? Is it a meaningful savings?

Maybe some are willing to increase friction at the bearings (& loss of power due to a thicker oil) just to shave a few seconds off warm up..but not me. I'd just as soon give it a little throttle to get things warmed up faster.
 
I have always felt, with a good stat, that cold start warm up was mostly from fuel/air combustion and piston/cylinder wall friction-with oil temps added later. Our '72 Vega was our first with an aluminum block (w/iron heads) That rascal took a while to get the gauge moving and heater/defrost in cold Michigan/Colorado/Minnesota winters. And it also cooled off really quickly on shut down. I later read a bit about such with cast iron and aluminum.
 
Originally Posted by Lapham3
I have always felt, with a good stat, that cold start warm up was mostly from fuel/air combustion and piston/cylinder wall friction-with oil temps added later. Our '72 Vega was our first with an aluminum block (w/iron heads) That rascal took a while to get the gauge moving and heater/defrost in cold Michigan/Colorado/Minnesota winters. And it also cooled off really quickly on shut down. I later read a bit about such with cast iron and aluminum.

I can just imagine the sense of horror & helplessness (not knowing if frost bite will set in before you pull into work) of sitting in the cabin of one of those 0w16/20 engines waiting for what seems like forever, for the temp to come up.

Chalk up another W for team "thick", in the thin v. thick wars!...

[Linked Image]
 
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Well, I run thin oil and my heater is putting out heat within a few blocks. Also the blue light signifying cold engine operation goes off. Granted that is not full operating temperature but a lot of this argument is grasping at straws.
 
I'm running 0W-20 and I'm at operating temp within 5 miles, checked using an OBDII reader. Operating temp meaning 176F coolant, which is when the Tstat opens. I imagine it takes another 5 or so for the oil to come up to a similar temp.

I think my relatively quick warmup is due to it being a 1.8 4cyl aluminum block. There's not a whole lot to heat up, only 1gal of oil and 1.5gal of coolant, so of course it warms up quick.

In real cold weather (0F and below) I have to block half the radiator or the coolant will never go above 160F, all the heat goes right into the cabin to thaw me out!
 
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I don't think cold thick oil will generate enough friction to speed the warmup process when you consider there are EXPLOSIONS taking place in the cylinders.
If cold oil IS generating that much friction, you have much more serious issues than worrying how quickly your engine reaches full temperature.

Also, low ambient temperature is the #1 cause of slow warmup
laugh.gif
 
I have a rather short drive to work (12 miles) and so when I drive the Corvette I make sure to use the paddle shifters and hold the rpm closer to 2000, because if I leave it in drive it always wants to be a couple of gears higher and keep the rpms closer to about 1200 or 1300. That makes a huge difference in the time it takes for my oil to get up to temperature, as well as it's peak too. For instance, if I leave it in drive it'll take about 8 miles before it gets the oil up to 190F, and then it won't go above that point. If I use the paddle shifters in manual mode and hold it in a lower gear, keeping the rpm at my desired range close to 2000, then the oil hits 190 after only about 4 or 5 miles and will reach about 210 shortly after that.

Unfortunately I can't do this in the Civic, so I'm pretty sure my oil isn't getting up to full temperature in that 12 mile drive in the winter.
 
One can argue that as a result of thicker oil warning up faster, it will also reduce engine wear since most wear happens during cold starts/operation. maybe the wear reduction is not that significant ... However I think that's one reason it's recommended to run the thickest oil that meets your W rating.
 
Originally Posted by OilUzer
One can argue that as a result of thicker oil warning up faster, it will also reduce engine wear since most wear happens during cold starts/operation. maybe the wear reduction is not that significant ... However I think that's one reason it's recommended to run the thickest oil that meets your W rating.




You mean run a 5w or 10w instead of a 0w?
 
Originally Posted by PimTac
So a 5w is thicker than a 0w? I'm having difficulty grasping this.


5W will have higher viscosity (cSt) relative to a 0W at cold(er) temperatures ... Since we are talking about cold start/operation and before the oil has reached nominal operating temperatures.
 
There are some obvious benefits (aside from your cabin heater pumping out warm air) to getting the engine up to operating temp as soon as possible..like reduced emissions for example. But I have to believe that BITOG isn't the only entity to contemplate such a question... like, maybe engine builders do/have? I mean, they obviously (have an interest in) would like to see the engine get out of running rich open loop as soon as possible. And if there was some practical way to accomplish this (warming the engine even faster) where the negatives don't outweigh the positives, we'd already see it in use in our engines wouldn't we???🤔
 
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Originally Posted by OilUzer
Originally Posted by PimTac
So a 5w is thicker than a 0w? I'm having difficulty grasping this.


5W will have higher viscosity (cSt) relative to a 0W at cold(er) temperatures ... Since we are talking about cold start/operation and before the oil has reached nominal operating temperatures.


Not always, it depends on what temperature you are looking at. M1 0w-40 is heavier than any GF-5 5w-30 at all temperatures much above where the W-rating is tested, at temperature at which very few people here will be starting their vehicle.
 
Originally Posted by OilUzer
One can argue that as a result of thicker oil warning up faster, it will also reduce engine wear since most wear happens during cold starts/operation. maybe the wear reduction is not that significant ... However I think that's one reason it's recommended to run the thickest oil that meets your W rating.


The reduction in wear as the engine warms is due to parts reaching the size they are supposed to be and the activation of heat-activated additives, not the viscosity. Thicker oil will initially shear more, thus creating more heat, but this thins it, so eventually it reaches a point where it is at the same shear rate as whatever you are comparing it to.

One of the reasons thinner oils are being chased by OEM's is that shearing that thicker oil causes more fuel to be burned, which impacts CAFE. Thus, if you can reduce fuel consumption during the warm-up cycle, you increase fuel mileage.

Not sure where the "recommend run the thickest oil that meets your W rating" is coming from? Are you perhaps thinking about VII dosing? In general, oils with a narrower visc spread have historically had a lower dose of VII, but that doesn't factor in base oil selection. You can make a pretty cheap Group II+ 5w-30 that will have more VII than a PAO-based 0w-40 for example, so its not exactly universal.
 
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