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Cold-temps Engine WARM-UP protocol....

XpedientJ

NAXJA Forum User
Location
MA
THIS was brought to my attention:

http://www.msn.com/en-us/autos/owne...d-just-harms-the-engine/ar-BBxuI1d?li=BBnb7Kz


- I've always been a big warmer-upper when the temps are cold, feeling that
it's important to get the oil up to a readily-flowable temp before making any
real demands on the engine, i.e. RPMs-wise.

- IF there is ice or sticking snow and, of course, if one is about to head out in
snowing conditions, it'll be critical to have heat on the windshield...

*Sure, an engine heater, whether oil or coolant...would be ideal, but....


THEN, regarding the assertions in the article....

....what say all YE....??
 
I,ll call BS on the "harms engine". I had over 400K on the OE engine in my 96.It would get at least a 10 min warm up on mornings when there was frost on the windows.
If that harmed the engine,I would have had to replace it much sooner,,,,
 
According to the article it says warm air comes before a warm engine. If the air is warm from heat transfer from the coolant and the coolant is warm from heat transfer from the engine, how is the warm air present before the warm engine? Sure the air is warm before normal operating temperature but the engine is still warm to an extent. At least in our cars that use the coolant heat exchanger for the heater.

Now cold engines do run rich but not for that long. And I personally would rather have my engine run at low rpms at idle when the oil isn't flowing ideally rather than push up the arms through normal driving when the oil isn't perfect yet.

But then again using the correct temp oil should flow nicely and correctly anyways. Warm up to the point of not harming the engine shouldn't be more than a minute or so if everything is working correctly no matter how you let it run. 800rpms is still a lot of "explosions" in a minute and trying to keep several hundred gasoline explosions from heating something up to 40 degrees fahrenheit would be impressive. The coolant warming up as it flows through will take longer to read on the sensor and hit operating temp then the o2 sensor's heating element which have a greater impact on running rich then the coolant temp.

Someone please correct me if I'm wrong.
 
I've warmed up every engine I've ever ran before revving them too much. Never had any issues. I've been thinking of installing extended idle switches in my two 98's to use on cold mornings. Then they wouldn't take so long to warm up.

The '01 my wife drives doesn't need it because it warms up pretty quick even in single digit temps. If I'm not mistaken the reason for the 00-01 head redesign was to get the engine heated quicker so it wouldn't run rich so long.
 
I always let my xj warm up ,put the one with 5 spd. in 3 rd and transfer case in neutral ,let then run 10 minutes or more. I don't like getting in a freezing car and they seem to run better after the warm up. Thanks
 
Thermal mass is why you get warm air before a fully warmed engine block.

In the winter, assuming temperatures are below 30°, start the engine and put the AW-4 into gear. Idle in gear for a minute or two and then drive off gently. Go easy on the gas pedal until the temp gauge rises about 1/2 way to normal, which even at -20° below zero only takes a few blocks of driving.

I have a plug in engine block heater on both of my XJ's and install them on my other vehicles too.
 
One of those no win situations. From my reading, one major flaw is the adhesion characteristics of oil. The EPA and auto manufacturers trying to meet fleet standards, lowered viscosity and use less oil adhesion additives to enhance MPG. It is an EPA thing, fleet average. Cold oil may actually be better as it tends to adhere better.

I've done flow tests on older oils and newer oils, the newer oils tend to flow better and adhere less. The deletion of adherence additives was an EPA mandate to save fuel. They think in millions of autos and the bottom line in fuel savings/reduced emissions. They could give a hoot less about engine or transmission wear or the energy needed for repairs or the energy costs of manufacturing replacement parts.

Against the law here to warm up longer than a couple of minutes. And there is always some busybody willing to call up and complain.

One place it can make a real difference is in the auto trans. Until the parts heat up and expand a little, there is a real chance of excessive slippage, especially in the older worn transmissions.

EPA has a for real linear agenda, they could give a darn what damage anything may cause if there balance sheet shows less emissions and less fuel.

Personally, I let it idle until the oil is flowing well, less than a minute and leave. I do baby it for the first couple of miles.

Joe average uses a couple of weeks worth of fuel in a year if he warms up ten minutes a day.
 
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I can say that my 95 achieves closed loop idle after 15 to 20 seconds of idle after a below freezing start. At start up it pulls afrs to 11.5 then gradually brings the afr to 14.7. The cylinder washing of carburated engines is valid. With MPI and heated o2 sensors, not so much.

That all being said start it, drive it easy until up to operating temp and then drive it normally. Yea I am saying cold start up and burn outs/WOT pulls is not recommended.
 
i have read that diesels dont like to be warm up idled. but rather vary the rpm a bit. but once warmed up its fine. that probably has something to do with the emission systems more than the engine itself.
 
Ford published a recommendation a few years back. It said that extended idling wasn't the best and said that as soon as the oil pressure came up, give it 30 seconds and start driving, just don't push it hard for the first couple of miles.

Personally I believe that the extended crank time on the 4.0L allows the oil pressure to come up before the engine fires, and prolongs the engine life.
 
What a lot of it comes down to is maintenance. Most people don't realize that idle time is miles, the general rule being 1 hr idle is 25 miles. While most people this isn't a big deal, we see it on a lot of fleet trucks at work. A truck may have 60k on it but enough hours to equal 200k. It's why most diesel manufacturers put engine hours on the display. New diesels the stupid amount of emmision garbage on them gets angry because they are designed to work in loaded environment, which is why they recommend reducing idle time. Extended drain intervals with cold temps and short drive times can lead to oil dilution which is really the problem, not so much the fact that you idled your car in the morning. So keep up on the maintenance and you should be fine. I have 290k on mine with a lot of idle time, still runs fine.
 
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