Run It To Full "Operating Temperature" Or Don't Run It At All?


#1

Airplane background:

I once worked at an airport for a Piper airplane dealer who ran the airport, sold planes, sold fuel, gave lessons, and ran a full airframe/engine shop. People would bring planes from very far away to be worked on by a particularly wise and expert mechanic there.



He would never let us start and taxi (drive) an airplane for a short distance. We would have to hook a tow-bar to it and physically pull and push.



The car part:

He said that starting a gasoline engine and shutting it down before running at full operating temperature was very detrimental. To this day I heed his advice when operating our cars and vehicles.



I think we all agree that frequent short trips in a car is tough on exhaust systems, engine oil, etcetera. I have heard horror stories of short-trip cars with water in the bottom of the oil pan and such.



The questions:

1) Do you subscribe to the advice of the wise aircraft mecanic (operating temperature or nothing)? Is it bunk or wisdom?



2) Do you have any horror stories evidencing damage to cars by short trip driving (water, excessive wear, etcetera)?



3) Do you have any stories of cars not being harmed by years of short trip driving (no excessive wear, oil consumption, water in oil, etcetera)?



CSA


#2

I subscribe to the same theory. If I am going to start my engine, I make sure that it is driven until it is up to full operating temperature.

Many, many years ago, while working at a gas station, I recall pulling the dipstick on a Pontiac, only to find that the dipstick was literally rust-coated, and the level of the “oil” was a few milimeters above the full mark. I suggested to the owner that he allow us to do an oil change right away, since it was obvious that he had severe water dilution of his oil.

His response was that he only drove a couple of thousand miles per year, all done in short-trip driving, so he was not due for an oil change. I told him that the conditions noted on the dipstick indicated a need for much more frequent oil changes, but he gravely corrected me by stating that he “couldn’t need an oil change” because he had only driven a thousand miles in the past 6 months or so, and “besides, I have plenty of oil–look how high the level is on the dipstick”.


#3

CSA:
I agree with the points you make, however I don’t let them control how I need to use a car.

I am forever driving short trips around town for activities that are far more important to me than the longevity of a car. So what if the engine lasts 50K miles less. The car is a tool to support the needs of my lifestyle.

On a related note, I remember 35 years ago reading a study done by Ford. They drove new cars around a track continuously for 100,000 miles without ever letting the engine get cool. They only stopped to get gas, change drivers, and change the oil.

At the end of 100,000 miles, they measured the cylinder wall wear. The amount of wear was equivalent to an engine with only 10,000 miles on it - not 100,000 miles.

To summarize, I do what I can to take care of my car, but in the end, how I need to drive it for my lifestyle is far more important.


#4

Your A&E guy gave wise advice.

Constant short trips hurt in a number of ways.

The parts are designed to fit their best when at operating temperature. Always running cold results in more blowby per miles run and thus more dilution and contamination of the oil. NOTE: some amount of blowby is normal in all engines, more so with age.

A cold engine runs richer. Richer + more blowby (see above) = more dilution of the oil.

Water vapor is a normal byproduct of combustion. The hydrogen atoms in the hydrocarbon molecues (gasoline) bond to oxygen atoms when the hydrocarbon splits (combustion) and form H2O…water. Until this vapor and the surfaces around this vapor warm up the water vapor condenses on the surfaces…and oxidization happens!

How much harm will be done long term by constant short trips is highly dependent on the operating environment. My son’s tC in LA would constantly be operating at higher temps and generating much less condensation on short trips than mine would here in NH where the climate is much colder.

However, our cars were bought to serve our needs. If one man drives 40,000 miles a year and another driives 3,000 miles a year they’ll both be looking for new cars in 10 years, just for different reasons. We need not be slaves to our cars.

Airplanes are a different operating environment. Airplanes get moved around for the purpose of better utilizing the ground on which they’re parked and/or to drag them in and out of the hangers for maintenance. It serves no purpose to be starting airplanes up and create the condensation just to change their parking spots…or to be hauling them in and out of he hangers.


#5

If the spyder is in my way, I fire it up and move it. I seriously doubt that the damage could be quantified. An airplane, on the other hand, would most likely be more quickly and easily moved with a tow vehicle. I have picked up the tail of a Piper and moved it like a wheelbarrow. Starting it and maneuvering it would have taken much, much longer.

Some parts wear. Some parts rust. Some parts rot. If you have need of a vehicle, use one most suited to your need and accept the innevitable fact that it will waste away like we will. But I’m a simple person, and I try not to sweat the small stuff.


#6
  1. I agree 100% with the mechanics advice, and I follow it most of the time. I try not to start the engine in any of my vehicles unless I will be driving it somewhere, and where I live anywhere I go is far enough to reach full operating temperature.

However, if I need to move a vehicle for some reason I will start it and move it. I let the engine run a minute or so, but not long enough to reach operating temperature. I try not to make a practice of this, but will do it if necessary.

  1. No horror stories. I’ve never used a vehicle for short trips only, so I don’t have experience with this.

  2. A friend had a Geo Prizm that was used mostly for low-speed trips in and around town, and the only real problem was a need to replace parts of the exhaust system frequently since it never got hot enough to drive off the moisture.

This problem was solved by going to a chain muffler shop that has a lifetime guarantee on its products. Every few years the car gets a new muffler or pipe for free. The guys laugh about it.

The car was maintained correctly, with frequent oil changes, and is still in daily use with around 200K miles on the clock.


#7

TSM, You’ve Shed Some New Light On The Theory.

Those of us in the north where winter is a 6 month season see those huge plumes of exhaust vapor when we start our cars. I think it makes us more susceptible to, or more conscious of, the water problem as it relates to a “cold” run time.


#8

My inlaws have a place on Nantucket and I think the theory is bunk. They own a 1990 Legacy wagon with about 50k on it. No real problems except for age related ones.

I will add trips are usually <1-2 miles. And it has had overland permits on and off over the years (driving on beach).


#9

Heck, CSA, I even see water RUNNING out of cold exhaust systems on really cold days.

I’m going to reach deeper and suggest that it’s a far more common sight on modern cars. In the days of carburators engines ran very rich, esecially when cold. Much less oxygen available per volume of hydrocarbons. I’ll speculate that today’s leaner running engines (especially when cold) have a much higher ratio of oxygen to gas available in the cylinder to bond not only to the carbon atoms (reducing CO levels in favor of CO2 levels) but also far more available oxygen atoms to bond to the hydrogen, forming more water vapor.

I suspect some people think something is wrong with their car if they see the water dripping profusely out the tailpipe. We’ve even had one or two post here in the past.


#10

Andrew, Thanks For The “Bunk” Rebuff. Interesting. What’s An “Overland Permit” ?

Is that an off-road use permit?


#11

answer to #1: Yes, I agree with the advice, but I’m not obsessive about it. Most of the time my cars reach operating temperature pretty quickly, if that’s what you mean by noting the temperature guage goes up to its normal reading. I like to think a longer trip on the highway now and again helps burn off condensed water in the crankcase and exhaust systems.

Ans to #2: No horror stories. Modern oils do a better job at lubing cold motors and my cars all call for 5W oils either 5W - 20 or 5W-30. These thinner oils circulate quicker than the oils of old. A lot of the water vabor and condensation problems impact on the exhaust systems where the water rusted them out prematurely. Today most exhaust systems are stainless steel and with CAT’s run hotter to burn off more water.

ans. to 3: No, I bought a used 2000 Camry in Nov. with only 68,000 miles for my son to use. It was as perfect as possible for its age. My main concern was the low mileage meant a lot of short trips. We are up to 75K now with no issues. Just changed the oil at 69K and again at 75K. I’m knocking on wood right now.


#12

Wow! Fifty thousand miles? That certainly proves your point!

I was using a 3 cylinder Geo Metro to make my 36 mile commute to work and with this extreme abuse, that little engine was already worn out in a mere 280,000 miles and it needed a new muffler once.


#13

First I would have to say that aircraft engines are designed to run under different conditions than cars and the penalty for having an aircraft engine fail during a trip can be much harsher than for a car engine.

The cost benefit advantage must consider the above.

If my car's engine fails on me, chances are I will be inconvenienced and a very remote chance I will be injured or killed.  I am willing to be a little less concerned about my car engine.  

That said, I tend to avoid short trips in my car.  However if I am running a short errand I am not going to just add miles to the trip to get the car fully warmed (I believe the cost benefit there would be negative, with more fuel and total wear done to the engine, and my time is worth something. 

 Making long trips out of short ones on a car is just foolish in my opinion as the damage done during a short trip would also be done during the first part of a long trip.  You are just doing additional damage.  

  On an aircraft, towing it rather than starting the engine does reduce wear so that makes sense, but it does not apply in any way to a car engine.

#14

Joseph, Well Stated.

I did consider the points about harsher consequences and higher costs pertaining to aircraft. I understand your driving rationale.

I’m not so sure that everyone will agree with " … the damage done during a short trip would also be done during the first part of a long trip. " and " … but it does not apply in any way to a car engine. " We’ll probably find out.

CSA


#15

I for one would have to respectfully disagree with that only because once warmed up the condensation will be carried away whereas if the engine is left cold the moisture will stay as condensation to create oxidization.

But I firmly believe that our cars are here to serve us. If our needs dictate only short trips, then that’'s how we should use them. The only change we should make is to use the “severe conditions” maintenance schedule. We shouldn’t obsess over this.


#16

Only certain people with certain licences are allowed to start and taxi aircraft (that’s how it was at my employer Jet Aviation in Zurich Switzerland) So no, the engines were not started simply to move the plane.

IMHO the city driving vrs freway driving,short trip vrs long trip comparisons were much more revelant in days gone by.

Many of the historical conditions about what makes or breaks a car (only one owner,only freeway driving,never using a certain brand of oil or filter,these type of things) are hold overs from the past

Look at the data quoted by Joe, it’s from 35 years ago.


#17

I for one would have to respectfully disagree with that only because once warmed up the condensation will be carried away whereas if the engine is left cold the moisture will stay as condensation to create oxidization.

That is true.  I was about to edit my original to explain my thoughts on that, so here it goes.

 I do take enough longer trips so any condensation does not really get much of a chance to build up.  Some people will have a problem with that, but just for one or two short trips between trips where the car does fully warm up are not likely to cause any problems over the life of a typical car.  (Note: follow the owner's manual's recommendations for any severe conditions.) 

 Just my opinion, but I doubt if this is something we should be all that worried about as long as we follow the owner's manual.  How often do we see problems caused by short trips when the owner's manual recommendations were followed?

#18

I wholeheartedly agree.

Have a great weekend.


#19

While I agree it is better to get it to operating temps, I can’t say as it really makes much difference in the long run. I start my car and drive it 50 miles. My wife starts hers and drives two miles. We’ve been doing it for years and the only problem I’ve had related to that is a few mufflers rusted out because of the water in it. When it is below zero, I think its more important to run it some to charge the battery up and stress keeping a full tank to reduce water. Other than that just go about your life and life style and don’t worry about it.


#20

CSA,

What that mechanic told you is right but also consider the fact that “Avgas” is way too expensive to burn just by taxiing around the ramp. He also probably didn’t want rocks/debris blown around the ramp by the running engine. I can vouch for all of this because I fly [Piper] aircraft in my spare time.

Just for the record I also avoid driving my vehicle unless I know its going to have a chance to warm up. The only exception is when taking it in for an oil change; my mechanic is 2 blocks from my house.

jmw