Motor warmup

[Mark McQuaide]

On the subject of engine temperature, what's the thinking on motor warmup procedure?

In the manual for my VW Passat, which had a 30V DOHC V6, it stated that you should never let the car sit and idle with a cold motor, the reason being you get the most wear when the motor's cold, so the quicker you warm it up the better. Is this true for the multivalve V8 in the MM?

[Macon Marauder]

Sure hope so. I don't know what the manual says, but I treat all my cars the same: just a few seconds after start-up. Maybe 30 seconds in winter.

Idling is rough on the engine IMHO.

[RF Overlord]

Mark, here's my 2 cents on that subject:

Beyond the initial few seconds after start-up, there's no additional wear on the motor whether it's cold or warm. The issue is that the motor is most efficient after reaching normal operating temperature. Letting a car idle is not the best or fastest way to get the motor to operating temp, allowing it to do some work is. A motor will actually warm up faster if the car is being driven than if it just sits idling. It's just that then you have to sit in a cold car, instead of it being toasty-warm when you get in it after idling in the driveway while you finish breakfast. Personally, as soon as the idle speed has dropped to normal (usually not more than 30 seconds to a minute), I drive away. Just don't lean on it until it's reached normal temp.

A secondary issue is that a cold motor puts out more emissions than a warm one, so warming it up quicker is better for the environment.

[schuvwj]

Mark I always TRY to start my cold MM by leting the RPM's slow to 1,000 rpm before I put it in gear. Just a habit!

[Mark McQuaide]

I thought maybe running it with thick, cold oil was where the extra wear was coming from. Letting it warm up slowly at idle obviously makes it run with cold oil much longer.

[schuvwj]

If you let your MM set out when it gets very cold Mobil-1 has a 0-30wt that would be very good for minimizing cold starting wear.

[LincMercLover]

I don't see any problem with letting a cold car warm up for a little bit before getting in and going. Just remember, it's not a diesel. Diesels are the only motors that can sit hours on end just idleing. Gas motors get restless after sitting at idle for long periods. Granted, it's not as evident in a FI motor, but a carbed. motor it is! Changing RPMs are a must for gas motors.

[Mark McQuaide]

Hope you didn't stain the leather!

Just this morning an Acura NSX lost it on an icy onramp just behind me and one lane over. I saw it coming the whole way, and I had to smile as I watched him fight it, overcontrol, and go sideways off the road (we were only going 20-30 MPH and he didn't hit anything). This time of the year you can't drive with a cranial-rectal inversion IMO

[RF Overlord]

Mark:

Allow me to clarify my earlier reply:

There's very little additional wear simply because the motor is cold; it's the initial start-up that produces the majority of the wear, warm or cold. As long as you're using the proper weight for the temperature, the fact that the oil is cold should not be a large factor.

The reason you don't want to lean on a cold motor is that the clearances on the bearings, etc., are only at their correct tolerance when the motor is at "normal" operating temp. Ditto for the transmission.

[Mark McQuaide]

Thanks for the info. There's a lot of opinion that goes around on this kind of stuff.

[RF Overlord]

Originally posted by Mark McQuaide
This time of the year you can't drive with a cranial-rectal inversion IMO

LOL! Every time I use that expression, no one knows what I'm talking about... :beer:

[LincMercLover]

Hmm... that post wasn't suppsed to make it to this board. Retarded school comps...

[SergntMac]

Schuvij told me at the Chicagoland Ownwer's meet, that I should at least wait for the bells and lights to go away before I pull out...Ya think so?

[schuvwj]

Sarge I did what?!?

[SergntMac]

No? Nevermind...

[LincMercLover]

I usually wait for my idle to come down a tad before taking off. Easier on the U-Joints.

[Donald]

Mark,

My car gets a bit dusty during the day. So in the morning I pull out of the garage and let it run while I go over the car with a California Car Duster. Nice and shiny when I hit the road.

Only to get dusty again. :-(

[LincMercLover]

LOL, it's black Donald, get used to it. If you notice, when you dust her in the garage, by the time you're done with the whole car, look back at where you started... MORE DUST! IT JUST DOESN'T QUIT!