Warming up engine when cold

Since I have techstream I thought I'd take some data points before and after idling following a cold start for 10 minutes.

There seem to be competing theories as to what is the least amount of wear on your engine and transmission. Either idle it for a while to warm it slowly, or get in and go (gently!) as a means of warming up the engine.

Factors that I believe come into play:
Thermal expansion/contraction
Fuel atomization and evaporation (cylinder wall washing)
Catalytic converter efficiency (not really a wear factor)
Oil viscosity and protection

Here are the numbers I posted, adjust up or down for temperatures at which you'd see yourself wanting to warm the vehicle. We've had a lot of zero degree mornings here lately.

Temps in F. Again, 10 minutes idle after cold start (also in garage with garage door cracked for ventilation. Probably higher net as a result of enclosed space)

Oil start: 34
Oil stop: 61
net: 27

Coolant start: 34
Coolant stop: 126
net: 92

AT start: 36.5
AT stop: 62.2
net: 25.7

Thoughts?

 

Fwiw, on very cold mornings, I do both- let it warm up for a few minutes and drive very slowly until the automatic transmission warms up (Scangauge II)


Looking forward to another interesting TW thread-thanks.

 

I'm unsure which TIS value that Scanguage is looking at but using my Torque pro with OBDII adapter, it doesn't read AT temps accurately...seems to match 1:1 with water temps so I believe they have the wrong value assigned. In any case there are also two different A/T Temp values, 1 and 2. 1 reads lower and is what techs are advised to use when doing things like checking fluid level.

 

Good data. I would need to see the same data on a similar morning from just starting and driving gently to draw any conclusions. I'm a believer in gently getting the engine to operating temp as soon as possible. So I'm not a believer in starting it and immediately throwing it into gear, but rather let it idle for 1-2 minutes (make sure everything is happy and settling in), then gently driving (limited throttle) until the temp is off the peg.

Also what position was the heater in? Did you have it at max heat and any defrost setting? Curious because that would cause the electric element in the heater core to come on and help with the warm up.

I just put a Katz cartridge style block heater in my 2018 and tested it this morning. It was 19 outside and the block heater had been plugged in for 2.5 hours; I started it and immediately read the coolant temp off the ODBII and it was at 68 deg F. After 3 minutes it was up 118 deg and blowing warm air. I was not at max heat or any defrost so no help from the electric element in the heater core (unless that thing automatically comes on at some low temp to help get the engine temp up as soon as possible).

 

I can do that!

 

Depends how cold it is---if its below 20 degrees where its uncomfortable to sit in the truck then i'll start it a few minutes before I am ready to leave. Otherwise I get in, start her up, get my music going, and im off.

 

It generally runs as I scrape ice and clean off snow. I take it easy on my 1/2 mile of gravel road until I get to the highway and then I don't flog the crap out of it getting up to speed.

 

I'm fortunate to never be exposed to zero degrees in so cal so I'm a start and drive kind of guy.

I'm not sure if it matters like years ago but maybe looking at the data for the oxygen sensors when they go from open loop to closed loop would help.

At least that was an argument about the long warm ups as o2 sensors and spark plugs would get more carbon build up but this is also before direct injection came out. I'd still think the O2 sensors would foul up sooner.

 

Oil viscosity using 0W-20 synthetic won't cause any issues with more wear. Either way is fine. I do both, warm it up and drive it easy for the first few minutes.
However, I do think this thread could make a mountain out of a molehill lol.

 

It's been single digits to -10's here for a week and even with the synthetic fluids used in these newest vehicles that are thin as ever, I've always warmed up a Vehicles motor before I took off, minimum- until idle comes down to normal usually 5-10 minutes depending on outside temps. Mostly because I want the warm heat before I jump in not to prevent engine wear. As far as which method yields least amount of wear, really only way to tell would be to tear them apart and take measurements of the parts after each method used. Lubrication is biggest part of wear, So quicker you get the lubrication to moving parts the less wear you will have IMO. What is the fastest way to lubricate a motor? I bet there will be as many different answers as there are members.

 

I take off after idle speed has stabilized, at a minimum; longer when it's cold out to let the PTC heater start throwing warm air.
When cold, I do baby it the first 3 miles(distance to freeway), mainly for ATF temp to come up.
If the temp differentials between ATF and coolant aren't within range, it should throw a DTC.

 

The 10 minute drive will show it but in the past I've seen oil temps take a LONG time to come up to operating temp in comparison to water temps...so romping on the gas when your water temps show good is still not advisable.

 

My coolant temp hits 100F in less than a mile going downhill from my house in 20°-30°F weather. That's enough to get the heat blowing. If I turn the other way and go uphill, it's even faster. Transmission takes much longer and I don't monitor oil temps on my Scangauge.

 

Anyone buy the Taco (car) starter??

https://www.ebay.com/itm/2016-2018-...Remote-Start-Kit-v2-1-Smart-Key-/272756857992

 

Do you think 'normal' operating temps equates to safe and/or appropriate?

 

Yes, our multigrade 0w-20 is designed to provide its minimum kinematic viscosity at 212F. Below that, I don't trust the oil to have the shear strength to provide adequate protection under high load conditions.

The 0w multigrade is designed to flow better when cold to help prevent startup wear in cold conditions. It's not designed to provide better shear strength when cold.

 

I thought you were talking about ATF oil because I had mentioned coolant vs ATF temp differential.