DP - Apply Throttle for Cold Weather Start? (That Depends)

[Rex_Haul]

My owner's manual oddly doesn't cover Cold Weather Starting (20ºF or -7ºC or colder) but I found a general Caterpillar Winter Operation Guide that called for 1/3 throttle till start. Then a couple of minutes of low idle followed by 10-20 min of 900 RPM.

It's been several minutes since I wrote that first paragraph. In between, I called Caterpillar directly and got my answer. The answer depends on the model and year.

I've decided to share what I have learned because info is scare online and some of the YouTube videos I saw were just plain wrong, if not downright harmful. Get the facts for your motor from the manufacturer...

But in my case, a 2005 Cat C7 requires NO throttle and it's air intake pre-heater will come on for several seconds and I am to wait till it's light goes out - THEN crank the engine. The light may come back on while I am cranking. The light may come on or flash even after the motor has started if it's cold enough.

I'm told that it will take 10 seconds of cranking, at those temps, after a month sitting, just to get the fuel pressure up and so forth, before the engine will think about taking off on it's own. Could take 30 seconds before it takes off.

HOWEVER, if it's not running after 30 seconds, stop cranking and wait two minutes for the starter to cool before trying again.

Run the block heater for at least two hours prior, longer if colder than what I listed above.

Make sure your fuel is fresh, winter fuel, (min. 45 cetane) that you are using anti-gel, anti-moisture solution and your batteries are topped.

Ether can only be used on certain engines, specifically NOT on engines with air pre-heaters (Boom!)

There you have a timely summary of what to and not to do. Anyone care to expand?

[Blaster_Man]

JetAonly wrote:
Good list!

The only thing I 'd add as an observation is that I typically use block heaters below 40F. I know the manufacturers don't require it, but I like the ease with which they start. Minimum block heater time I use is 4 hours. If temps are below freezing I also use the engine heat function of the Aqua Hot. Typically, when planning a cold start I will use both all night. Doing this an I see 100F on the coolant temp in a few minutes.

Same here. When the engine block heater has been on prior to start, the "wait to start" light does not even come on since the coolant temp is always over 100 degrees.

[uncle_t]

dsdp

I have been wondering why my voltage gauge hops around after a cold weather start. now I know and thanks.

[DSDP_Don]

Here is something that sometimes throws people off. When cranking in cold weather and the intake heater is cycling on and off, you may see your volt gauge drop way off and then come back, The intake heater draws a lot of juice. People often think they're having voltage issues.

[RVUSA]

JetAonly wrote:
The only thing I 'd add as an observation is that I typically use block heaters below 40F. I know the manufacturers don't require it, but I like the ease with which they start.

you're doing the right thing. The main importance of block heating is reducing the chance of cold oil starvation. It doesn't splash well at all when it's the consistency of syrup and the cylinder walls need a lot of oil.

Along with poor splashing it is also hard to pump and the rod and main bearings can really take a beating if you run up the rpms before the oil warms up. Friction and wear really goes up if you hammer it cold.

[JetAonly]

Good list!

The only thing I 'd add as an observation is that I typically use block heaters below 40F. I know the manufacturers don't require it, but I like the ease with which they start. Minimum block heater time I use is 4 hours. If temps are below freezing I also use the engine heat function of the Aqua Hot. Typically, when planning a cold start I will use both all night. Doing this an I see 100F on the coolant temp in a few minutes.

[wa8yxm]

Mike and Trish wrote:
You mean cetane, not octane. Opposite measures, more or less -- octane is a measure of resistance to pre-ignition (knocking), relevant to gasoline, while cetane measures combustibility, relevant to diesel engines. (These are rough definitions, which someone will undoubtedly correct me for.)

Id say close enough.

Octaine: Ability to RESIST ignition due to heat and compression

CETANE: Ability to IGNITE due to heat and compression,

That is how I leaned it, And you did say "Roughly", I'd have to use the same term to describe what I just typed.

In either case... THe poor guy either has typlexia (Which many of us have) or needs to re-read the O/P and notice it's a D not a G engine.

Typelexia happens when the fingers get ahead of the brain. (And recall flamers.. I did say "us" when I spoke of having it).

[wolfe10]

http://en.wikipedia.org/wiki/Cetane_number

[Rex_Haul]

Thank's folks, I have corrected my post.

In diesel you're looking for a cetane (not octane) rating of 45 to 55. basic diesel is 45, synthetic is 55.

[Mike_and_Trish]

You mean cetane, not octane. Opposite measures, more or less -- octane is a measure of resistance to pre-ignition (knocking), relevant to gasoline, while cetane measures combustibility, relevant to diesel engines. (These are rough definitions, which someone will undoubtedly correct me for.)

[WyoTraveler]

I think diesel is down around 45 octane. In my farm equipment I use #1 diesel or the additive to prevent gelling. Sometimes in the fall it gets cold before they start delivering#1 to my tanks.

[Mike_and_Trish]

Rex Haul wrote:
Make sure your fuel is fresh, winter fuel, (min. 87 octane) that you are using anti-gel, anti-moisture solution and your batteries are topped.

That 87 octane fuel might run funny in your Cat C7 ...