B20VtecVillain

Ok so after having this conversation with several people in the shop I felt compelled to post online as well. It has come to my attention that the age old argument of whether warming up your car before driving is necessary or just a waste of gas/carbon build up. Many people are of the belief that warming up a car is not necessary because the oil will circulate within seconds of the engine starting, and as long as you don't thrash on a cold engine hard no harm can/will result. I am here to tell you that is 100% false. Oil circulation is only part of the equation. Looking at oil weight for modern cars you will see two numbers with a W in between. That W stands for "Winter" and shows us that the oil will have two different weights/viscosities (thickness which effects lubrication properties) depending on the temperature of the oil. The engines are designed to run at operating temperature, which is why it is called OPERATING temperature, and this are designed to run with the WARM viscosity of the oil, not the cold viscosity. What this means in basic terms is that when the oil is cold it cannot completely reach and cover all the points where it is supposed to lubricate and protect parts until it is at operating temp. This is the cause of 75% of premature engine component wear. (Such as bearings.) Ideally you want to have the most lubrication possibly for longest engine life, and therefore want to minimize driving with the oil in its cold configuration whenever possible. Also, we can establish already that not properly warming up an engine over its lifetime will without a doubt shorten its life span. (Service life) Next we must remember that oil is not the only component in our cars that changes with temperatures. Our cars run belt drive systems for the accessories and sometimes the timing/can control as well. (Model depending) Rubber expands and contracts with heat, and belts are made of rubber. This shows us that our belts are a different size when cold than when at operating temperature. (That key word again) Running a cold belt at higher RPM than idle is accelerating wear and stretching of that belt, which in turn causes, again, premature failure. There are also many other fluids and components in the car which are temperature sensitive, and I won't go into them all because hopefully you get the point already. Also, think of it like this: when was the last time You flogged your car on the dyno or Ran it down the 1320 or on the road course/AutoX track on a cold engine? Probably never? Well driving around cold is just SLIGHTLY less damning than those activities, so why would that be OK?
Like most of you I like to hear actual evidence behind things, so I close with a great example of an experiment I've done without even planning. A couple years ago I built two identical B18C engines; one for my DC2 daily and one for my GF EK daily. We both drive almost identical distances daily so at the end of an 18 month period we both had put almost an identical 11k miles on the engines. Our driving habits are very similar, I change the oil/fluids at the same intervals and we both get gas from the same stations. The ONLY marked difference between the two are that in the morning I let my car idle for 5-6 minutes until the temp moves, and she gets in the car, starts it, turns the radio on then drives away. We both moved onto new cars at the same time, and I wanted to use the currently stock B18s for other projects so I tore them both down over time. The rod bearings in my B18C looked essentially new, yet the bearings from hers had substantial wear already. Both cranks went to the same machine shop, both engines were properly clearanced etc. The variable here was feeding the engine RPM on a cold engine vs not doing so, period. The visible difference in the two engines was astonishing. Even the piston walls showed slightly more wear in her engine than in mine, which again, looked brand new. I will look for pictures of both tear downs to post if anyone is interested. Bottom line is, warming up is NOT a waste of your time/fuel. You do not need to wait until your car is fully warm to drive it, but waiting atleast until the temp gauge moves one notch is a beneficial process that WILL contribute to a longer service life of your engine components and accessories. The End. All comments welcome but I will tell you inadvance if your going to argue this point, bring some data with you because I have PLeNTY to back up my saying it's not a futile effort to warm up an engine.

v4lu3s

Letting it idle with low oil pressure and low flow is not helping your engine, especially with it running rich to warm up faster...that's going to reduce oil on cylinder walls and increase wear.

TomCat39

This statement would indicate the engineers designed the engine to not have enough cold flow at idle to supply the engine.

That would be a very bad design.

It's much more likely the engineers designed in a minimum cold flow at idle to amply supply the engine at idle when cold.

Caoboy

That's a much better way of presenting this argument.

I would agree, letting the engine warm up may decrease wear as the oil is heated up and the viscosity changes.

However, two identical engines will have differing wear patterns just because of minute differences in tolerances.

You say driving habits are near identical, but how about daily commutes? If one has more highway versus the other whom has more stop and go, this is a variable that can change the wear rates of each engine.

Many things, while putting together near identical engines (perhaps one engine had slightly looser tolerances, but the other had been built slightly tighter) can factor in increased wear.

Lastly, did you actually measure before and after bearing thicknesses of each engine to determine the amount of wear? Or the bore of the cylinders? Or the crank and rod journals? That amount of wear, in my opinion, would determine much more than just a visual.

TomCat39

I wanted to edit his post to add paragraphing too but I don't have mod status here.

B20, you attribute the wear to the temp of the oil. There is also the point of cold metal. If the gauge from the head is starting to move, most of the metal is a fair amount hotter than when cold. That would also mean the tolerances are a lot closer than cold. This should mean less wear.

No amount of oil is going to fill the larger gap when everything is stone cold to stop the wear unlike once it heats up and the gaps close up....

I tend to think wear is less if you let the engine start to warm up before you go over starting and immediately taking off, even if gentle (most people aren't gentle though). But I tend to think it has more to due with metal expansion over the viscosity challenge.

Knowing reality though, I bet it's a combo of both instead of one or the other.

holmesnmanny

No purpose whatsoever to warming a car up. When you drive it it's going to warm up right ?

TomCat39

I don't even see a logical reason for this claim let alone any data to substantiate it.

The larger gaps alone when cold will mean more force being placed on wear parts until the gaps close up so the oil itself allows the parts to ride the oil with no play.

Then there is the point that it is assumption the engineers factored in cold flow in the equation. If the oil pump is old and tired, this could also play a large role if the design is even remotely borderline to start with.

Can you substantiate your opinion at all or can it be disregarded as unsubstantiated random opinion?

holmesnmanny

You want to quote the engineers? Find me anywhere in the either the Honda service manual or the Honda owners manual where they recommend in any capacity to warm up the engine before driving it.

Then tell me exactly how you are not simply wasting gas by warming up the engine before driving it.

But if you want to waste gas, then do it.

TomCat39

That's like asking for a manual that states to pound the motor to break it in when brand new..... Most manuals now a days say baby it which is not proper to break it in.

Or lets look at it this way, you are essentially saying that getting punched from 2 inches of 20 inches squared acceleration is going to hurt or receive the same force as getting punch from 6 inches of 20 inches squared acceleration.

This is just not true.

However, is the wear noticeable anytime soon.... No. The reality is, engine last 17 years instead of 25. Are you even going to relate cold driving to the 8 years loss. No, you are not even going to be aware there is 8 years loss as it's been 17 good years of use by the time it dies.

In today's disposable world, instructions are not typically for longevity. They are for monetary purposes.

P.S. I've already played devils advocate to my argument and come up with a strong possible retort.

tony_2018

OK. Plot twist. What if the car has an automatic. Most cars shift rough if the fluid isn't warmed up.

Caoboy

plots within plots, Honda transmissions shift rough anyways

TomCat39

Oh man, well that kills all theories except OP's

I was actually thinking along the lines that the oil temp was the catalyst for the bearing wear while the metal temp and different expansion rates of the metals was the catalyst for the cylinder wear (punching at acceleration).

You know, I think a study of a large amount of vehicles in an artic climate versus one in a tropical climate could possibly prove wear from cold running vs warmer running. If you do enough of the same production cars in each zone and examined them all after x time driving with x parms... I bet it could possibly shed some real light on this debate.

TheShodan

iTrader: (14)

I love this thread. I may make this a sticky.

holmesnmanny

No need to try to change the subject. We're talking about "Warming up your Honda before driving, necessary or waste?"

On older cars with a choke you would set the choke when warming up the car to help it warm up properly. I know of no fuel injected cars with any type of starting directions, definitely at the least, Honda's don't.

It's funny you failed to see the logic in my post when it was simply common sense. As I said, if you want to waste gas, and, thereby, money, go right ahead. If Honda wanted you to warm it up a certain way, they woulda told you.

TomCat39

This assumes overall honesty/transparency and the consumer as priority, which I would argue, the world tends to say otherwise.

The damage, if there is any, is so slow there is no warranty or recall issues to be concerned about so the consumer risk management is essentially non existent in regards to this issue of contention. There is no purpose to advise the consumer on any "trade secrets and/or research" on how to best maximize the longevity of the motor by supplying or denying these "common sense or not so common sense" instructions. There is no risk involved in letting the motor not have maximized life. There is actually more money if it can outlive warranty and need significant repairs a reasonable time after. In reality it only needs to outlive the typical or average time of first owner status. This boosts parts sales, other automotive based industries, as well as car sales both new and used. It behooves the system to have a fair amount of secrecy, conflict and confusion and suppression.

Common sense says if there is no repercussions for accelerated wear, the money in the world is going to suppress information known to decelerate said wear.

holmesnmanny

You're saying every single automaker in the world is colluding together to keep you from warming your car up so it won't last more than 10 years ?

2LEM1

iTrader: (1)

Why not, every single manufacturer says to baby the car the first 500 miles too.

TheShodan

iTrader: (14)

Indirectly... Actually, yes. It's been like that for many years, although not officially from some OEM Manufacturers. It's called "Planned Obsolescence
https://en.wikipedia.org/wiki/Planned_obsolescence

An example:
GM rediscovers the value of planned obsolescence

In the grand scheme of things, Honda , Nissan, Toyota and even Ford Europe for a while didn't want to go that direction, so building high-quality , long lasting , and thoroughly-progressive manufacturing methodology was a sense of pride., But they didn't sell many vehicles that way, and people held onto them longer. So, even though some quality standards weren't necessary ignored or not considered, they did cut some of the cost by not putting in crucial information regarding best practices as to how to keep a car (especially a Honda) for an extremely long time. They did it for several reasons.

1) 90% of the owners didn't read the manual in detail and left it to service departments to fill all the gaps. unless you were a service technician, (in which your manual was completely different anyway), the everyday service manual was just a fat notebook to give the driver /user the basics for their maintenance & longevity , and nothing long term. No need for other illustrations or "tips", because, that would make the book larger, which meant it would cost more to make.

2) Most drivers of any of the OEM markets really didn't care. Look, as much as we love our cars and feel that it's "common sense" to do certain things to keep the machine well-maintained, the fact is, the automobile is the modern-day horse; feed it (with fuel), keep the legs moving (tyres / oil) and shine its coat once in a while (washing/ detailing). Once the car got older, or required a bit more care, instead of looking at it from a cost/benefit perspective, like an old horse, they would sell it before it got too old, or damn.. just shoot it, so that they could get another one.

tony_2018

TomCat39

@tony 2018 - hahaha good one

To illustrate supportive evidence of what TheShodan, 2LEM1 and I have said.

Just looking at the FSM 92-95 through both the "Standards and Service Limits" and the "Maintenance Schedule" this should have everything if the manufacturer was disclosing everything.

And yet, there are wear items that are not listed as they typically last longer than required.

• Wheel Bearings
• Bushings
• Coolant Hoses
• Engine Rebuild/Replace

And I'm sure everyone can probably think of a few more not on those lists.

tony_2018

Windows
Windshield
Carpet
Seats
Door panels
bulbs

TheShodan

iTrader: (14)

I meant to the effect of just let it run to the ground and not take care of the car. Not set it on fire as part of insurance.
I see where you could get that summation very easily.. I guess I didn't word it properly to go along with my horse analogy. Oops

holmesnmanny

You still haven't stated what benefit you can get out of warming your car up. As I stated originally, there is no difference between letting it warm up by idling and you driving the vehicle to warm it up.

2LEM1

iTrader: (1)

Just to play devil's advocate, I don't warm up the Focus for **** in the mornings. I mean, maybe 5-10 seconds. But that's it.

Of course, I also keep it in vacuum and don't blow 20psi through it down my street either.

TomCat39

The debate is that you get less wear when you let your engine warm up to some degree before loading it.

You claim there is no difference. We claim there is.

The difference between our claims, is we have provided data and reasonable possible theories to support our view.

You have only provided your view.

And lets counter a point of your view. You claim it's a waste of gas.

After 5 minutes the O2 sensor is up to operating temperature. Fuel trim then begins to work instead of working in open loop mode where maximum gas is pumped for any given RPM. At unloaded idle, the amount pumped is less than any rpm loaded. Now I don't have the fuel tables to sit down and do the math, but I am willing to bet it doesn't take but 15 minutes of driving warm to make up the difference of the 5 minutes of fuel wasted idling at no load. And I am willing to also bet it's still less fuel than you use in the 5 -15 minutes of driving you have to wait for the car to warm up while driving (cold air from moving prolongs warm up time).

I highly suspect your claim can easily be proven wrong with the fuel tables and a calculator.