Is there any practical benefit to letting a passenger car oil warm up before driving?

ZeeOSix

$100 site donor 2022
Joined
Jul 22, 2010
Messages
34,363
Location
PNW
Modern engines are built to MUCH tighter tolerances and don't require the warm up of yesteryear.
If the parts tolerances are tighter, I'd be letting it warm up a bit more, not less to let the dimensions settle a bit from thermal expansion. And I agree, they are not "MUCH tighter" if you actually compare the parts tolerances over the last 40 years.
 
Joined
Sep 29, 2009
Messages
2,971
Location
Deep in the heart of Jersey
I've heard it said alot thru the years that most engine wear occurs at start up. Could that be because cold oil doesn't flow as fast thru the engine, as warm to hot oil does ? I'm sure everyone on this site has seen the tests where oil comes out of a freezer in a glass tube at 20 degrees f, and is poured out and timed to see how long it takes to go about 10 inches. It doesn't move anywhere as fast as warm oil does. So that tells me your not getting alot in the way of wear protection by taking off as soon as the engine fires off. I let my old Ford Exploder idle between 2-3 minutes before I start driving. Especially in cold winter months. No clicks ,no ticks, no funny noise's, the engine has never been opened up 280k miles.,,
 
Joined
Jan 7, 2022
Messages
412
Location
Chicago
My 07 Acura tl was an ultra low emission vehicle and would run rough for a couple minutes on a cold start. Honda programmed it to intentionally misfire when cold to heat up the cat quicker. I never drove it till the idle smoothes out and everything was warmed up. I moved on to infiniti
so don't know if Acuras still do that
 

ZeeOSix

$100 site donor 2022
Joined
Jul 22, 2010
Messages
34,363
Location
PNW
I've heard it said alot thru the years that most engine wear occurs at start up. Could that be because cold oil doesn't flow as fast thru the engine, as warm to hot oil does ? I'm sure everyone on this site has seen the tests where oil comes out of a freezer in a glass tube at 20 degrees f, and is poured out and timed to see how long it takes to go about 10 inches. It doesn't move anywhere as fast as warm oil does. So that tells me your not getting alot in the way of wear protection by taking off as soon as the engine fires off. I let my old Ford Exploder idle between 2-3 minutes before I start driving. Especially in cold winter months. No clicks ,no ticks, no funny noise's, the engine has never been opened up 280k miles.,,
Parts the are directly supplied by the oil pump will get lubrication very quickly, if the correct cold viscosity (xW=Winter) rating is used for the start-up temperature. For parts that are lubricated by oil splash, obviously those parts may not get adequate lubrication until the oil warms up some. How splash lubricate parts get oil supply is mainly determined by the design of the engine and how the splashed oil is produced and where it goes while the engine is running. Engines with oil squirters will supply a better flow of oil to the cylinders and pistons than one without squirters.
 
Joined
Sep 29, 2009
Messages
2,971
Location
Deep in the heart of Jersey
Parts the are directly supplied by the oil pump will get lubrication very quickly, if the correct cold viscosity (xW=Winter) rating is used for the start-up temperature. For parts that are lubricated by oil splash, obviously those parts may not get adequate lubrication until the oil warms up some. How splash lubricate parts get oil supply is mainly determined by the design of the engine and how the splashed oil is produced and where it goes while the engine is running. Engines with oil squirters will supply a better flow of oil to the cylinders and pistons than one without squirters.
The more heat you put into the oil, will definitely help the squirters do a better job.,,
 
Joined
Aug 7, 2018
Messages
122
Location
WI
If it's above 20F, I don't usually worry about letting it sit and run to warm up. I get in, start my van, put my seat belt on, check everything, and go making sure to drive it gently until the engine gets up to temp, at least a quarter way up the temp gauge. If it's getting down close to 0F or lower, then I will let it run for about 10 minutes some days before driving it.
 
Joined
Apr 12, 2013
Messages
80
Location
44'N/88.5'W
As an example of tighter tolerances; We had a Toyota V8 engine in the shop. We had to tell the owner we can't machine his heads flat again as it will likely throw off his timing due to chain slack because of a loss of clearance on the deck. So he's got to hope the block is still flat and find new OEM heads...but at this point probably best just to find a used engine. This is not unique to Toyota. A number of new all aluminum builds can have the same issue.
 

OVERKILL

$100 Site Donor 2021
Joined
Apr 28, 2008
Messages
53,001
Location
Ontario, Canada
As an example of tighter tolerances; We had a Toyota V8 engine in the shop. We had to tell the owner we can't machine his heads flat again as it will likely throw off his timing due to chain slack because of a loss of clearance on the deck. So he's got to hope the block is still flat and find new OEM heads...but at this point probably best just to find a used engine. This is not unique to Toyota. A number of new all aluminum builds can have the same issue.
There wasn't a thicker head gasket available to take up what would be lost in the milling process?
 
Joined
Dec 24, 2021
Messages
60
With a standard passenger car, toyota camry, is there any mechanical benefit to letting the oil warm up in standard midwest winter, 10 - 30F, temps? When doing an oil change I noticed oil at operating temps runs out like water. About an hour later when draining the oil collection pan at 50F garage temps I noticed the oil ran like maple syrup. This is using a 5 30W synthetic oil. When it gets down to 20F I would imagine it runs even thicker. I am thinking that the car is designed to run best at stabilized operating temps where the oil runs like water. How much, if any, does the extra thickness of 20F oil wear the engine? Standard practice with fuel injected engines is they don't need any warm up but is there any benefit to letting the engine come up in temp just a bit and give a minute or two to warm the oil up to 100F or so?
I’ll leave it sit running 5 or 10 minutes when it’s a little cold out.
I always hear about fuel dilution being a potential problem with that but it hasn’t seemed to kill my vehicles yet.
I do always use a thicker oil than called for as all my vehicles spec 20or 30 grade oils and I just have never used thinner oils much.
Maybe that helps maybe not but a couple of my cars are getting up there in miles and are still alive so
 
Last edited:
Top