Auto repair myths

[IronWing]

Originally posted by: npoe1

Originally posted by: waggy
red makes the car faster!

My blue motorcycle is faster than your red motorcycle.

And it leaves a pretty cue chalk like streak when ya dump it.

 

[IronWing]

Originally posted by: foghorn67

Originally posted by: WhoBeDaPlaya

Originally posted by: foghorn67
Simply start the car, and drive it gently until it warms up.

That's what I've been doing, since I have to pass through residential and school zones anyway. How cold is extreme cold though? 0F? -20F?

The expception for cold weather starts doesn't really have to do with the oil. I think it has something to do with the different types of metals expanding at different rates when warming up to abruptly. Causing valve malfunctions and engine seize.
For example my forged pistons have the familar 'piston slap' noise until warmed up.

But most people who warm their cars up aren't doing it for the benefit of the engine. They do it mainly because they want the heater to warm up the cabin. Also, they are trying to charge the battery so the car doesn't die when put in gear.

 

[lupi]

Can we get a faq on this thread. Half the people sound serious about what they're saying while the other half seem to be joking.

 

[mugs]

Originally posted by: lupi
Can we get a faq on this thread. Half the people sound serious about what they're saying while the other half seem to be joking.

The problem is that people are stating myths like the OP requested, but people are interpreting them as statements of fact instead of examples of myths. Perhaps it would be more clear if people prefaced each myth with something like "MYTH:"

Edit: List started here: http://www.at-wiki.com/wiki/index.php/Car_myths

 

[gsellis]

Originally posted by: BoomerD
Gasoline is gasoline, regardless of where you buy it.

Sorry, this is NOT a myth. The gasoline you buy is almost never 'made' by the company you buy it from. After delivery from the pipeline, the brand is then distinguished by additives.

 

[gsellis]

Originally posted by: shabby

Originally posted by: Zolty
Blinker fluid needs changing every 15k miles, or until it turns a green color.

Oh snap, mine needs changing!

Wait, this is not true? Then splain to me why old folks in Florida have stuck blinkers? I am sure it is old blinker fluid.

 

[Zee]

Originally posted by: PingSpike
The whistle goes woo woo.

LOL that's freaking awesome. the whistles go WHOOOOOOOOOOOOOOOOOOOO lol

 

[Pacfanweb]

Originally posted by: foghorn67

Originally posted by: WhoBeDaPlaya

Originally posted by: foghorn67
Simply start the car, and drive it gently until it warms up.

That's what I've been doing, since I have to pass through residential and school zones anyway. How cold is extreme cold though? 0F? -20F?

The expception for cold weather starts doesn't really have to do with the oil. I think it has something to do with the different types of metals expanding at different rates when warming up to abruptly. Causing valve malfunctions and engine seize.
For example my forged pistons have the familar 'piston slap' noise until warmed up.

That's because your forged pistons expand more than cast pistons, and therefore require more piston to wall clearance. So they slap when cold, simply because there's more room for them to wobble.
The vast majority of cars don't have forged pistons, so this isn't a problem.

 

[gsellis]

x. You should fill your car when it is freezing out as you get free gas because it is denser.

y. Oil change places will help you find real problems with your car.

z. When skidding, you only need to steer into the skid to save it.

aa. Grooves in a tire help grip the road better (this one was believed until somewhere in the 60's!)

bb. The max cornering force a car could have is 1g (believed until ground effects were discovered.)

 

[Rubycon]

Originally posted by: Zee

Originally posted by: PingSpike
The whistle goes woo woo.

LOL that's freaking awesome. the whistles go WHOOOOOOOOOOOOOOOOOOOO lol

What in the world were they thinking????! :Q

 

[exdeath]

Originally posted by: Zenmervolt

Originally posted by: MercenaryForHire

Originally posted by: BoomerD
Running premium in my Honda really improves the performance...

1. S2000
2. CBR



- M4H

I was just going to say that if the vehicle is designed such that the knock sensor can accomodate premium with the allowed timing adjustment range then putting premium in really will improve performance.

ZV

You're just getting the factory rated power with the proper fuel the engine was designed for in the first place instead of the knock sensor nerfing it because of crap fuel. So you aren't increasing performance; it would be better to say you aren't nerfing performance anymore.

 

[BD2003]

Originally posted by: Pacfanweb

Originally posted by: foghorn67
Myth: Warming up the car will ensure everything is well lubricated on startup.
Exception: EXTREME cold weather.

With today's oils, there's really no reason to warm the car up at all. By the time your engine catches and you can physically let go of the key, the oil is everywhere that the pump pushes it to.
As you said, unless in extreme cold, you can start it and drive it like you stole it with no repercussions.

I've talked to a couple of Ford engineers that agreed with me on this when I was trying to get this argument settled.

I really don't know about that. You're going to have a hard time convincing me to go full throttle before the car is fully warmed up. Hell, my car wont even let me near redline until its half warmed up, and even then, I have my doubts that its fully safe.

 

[exdeath]

Originally posted by: IGBT
..premium gas is special and necessary.

Uhm... yeah... it's called auto ignition and knock resistance.

In engines with high compression or forced induction premium is a must.

 

[shortylickens]

Originally posted by: RGUN

Originally posted by: shortylickens

Originally posted by: junkiefp

Originally posted by: Pacemaker

Originally posted by: Vic
AWD/4WD helps you brake in slippery conditions.

I have never heard anyone say that, but it's really stupid. Just goes to show that people don't know what the acronyms mean.

Hate to explain it to idiots but it does when you downshift...

FTW!

Downshifting and/or engine braking in slippery conditions is much better than using the brake pedal.
And better control means less of a need to brake in the first place.
But the original point still holds true: Vehicles have 4 wheel brakes regardless of drive.

As for the halogen/blue lights I wish more people would get a clue. Those things dont help you see shiate.
I helped a guy change his headlights one night. We went driving around town and he was like: "Dude, these things suck!"
They look really cool and annoy the crap out of the other drivers. Give them up.
Spend the money on something that will help you, like a garfield toy with suction cup hands.

WHAT?? So you're driving along an icy road and you need to slow down, apply brakes and use all the wheels and the ABS safety net OR downshift to a lower gear therefore making power application much less smooth and risk locking the wheels? yeah thats intelligent alright.

Much more intelligent than ASSuming the vehicle in question has anti-lock breaks. If you wanna make an ass out of yourself fine, dont inflict your ignorance and stupidity on me.
As it so happens, my current vehicle is a little older and doesnt have ABS. But it has 4 wheel drive and 4 proper winter tires on it.

Incidentally, questioning someone elses intelligence does not enhance yours. It only makes it easier to point out how dumb you really are.
Now please go to bed and let the grown-ups finish their conversation.

 

[DrPizza]

Originally posted by: gsellis

Originally posted by: BoomerD
Gasoline is gasoline, regardless of where you buy it.

Sorry, this is NOT a myth. The gasoline you buy is almost never 'made' by the company you buy it from. After delivery from the pipeline, the brand is then distinguished by additives.

(not myth) - around here, there is one primary distributor to virtually all the gas stations. It's the same tanker that fills the gas from station to station. You can follow the same tanker around from Mobil station to Sunoco station to...

 

[thetxstang]

Here's a myth I learned of recently: I'd always heard that running your car on Max A/C was harder on your cooling system than running it in Normal A/C mode. An automotive A/C technician that I know and trust recently explained that this is not the case at all.

Evidently, when running your car in Normal A/C mode, outside air is allowed to blow over the evaporator core, which, since the outside air is usually much warmer, makes it harder for the evaporator core to cool and do its job. Conversely, when your A/C is set to Max, the air is set to recirculate mode, using the already cooled cabin air to blow over the evaporator core.

He also said the following method is the best way to cool the inside of your car on a hot summer day: Use the Normal A/C setting for the first couple of minutes or so, then set your system to Max A/C. Maximum cooling and the most efficiency, FTW!

 

[DrPizza]

Originally posted by: shortylickens

Originally posted by: RGUN

Originally posted by: shortylickens

Originally posted by: junkiefp

Originally posted by: Pacemaker

Originally posted by: Vic
AWD/4WD helps you brake in slippery conditions.

I have never heard anyone say that, but it's really stupid. Just goes to show that people don't know what the acronyms mean.

Hate to explain it to idiots but it does when you downshift...

FTW!

Downshifting and/or engine braking in slippery conditions is much better than using the brake pedal.
And better control means less of a need to brake in the first place.
But the original point still holds true: Vehicles have 4 wheel brakes regardless of drive.

As for the halogen/blue lights I wish more people would get a clue. Those things dont help you see shiate.
I helped a guy change his headlights one night. We went driving around town and he was like: "Dude, these things suck!"
They look really cool and annoy the crap out of the other drivers. Give them up.
Spend the money on something that will help you, like a garfield toy with suction cup hands.

WHAT?? So you're driving along an icy road and you need to slow down, apply brakes and use all the wheels and the ABS safety net OR downshift to a lower gear therefore making power application much less smooth and risk locking the wheels? yeah thats intelligent alright.

Much more intelligent than ASSuming the vehicle in question has anti-lock breaks. If you wanna make an ass out of yourself fine, dont inflict your ignorance and stupidity on me.
As it so happens, my current vehicle is a little older and doesnt have ABS. But it has 4 wheel drive and 4 proper winter tires on it.

Incidentally, questioning someone elses intelligence does not enhance yours. It only makes it easier to point out how dumb you really are.
Now please go to bed and let the grown-ups finish their conversation.

Your profile says "Guam." Get much ice on the roads down there?!
Unless you're riding the clutch, downshifting on very slippery roads is pretty stupid, with or without ABS. Here's a nice, scientific explanation: there's a maximum amount of force that friction can possibly provide to your vehicle. Once your tires start slipping on the surface, the coefficient of friction drops (the difference between the static coefficient of friction when the tires aren't sliding to the coefficient of kinetic friction when the tires are sliding wrt to the road surface.) Downshift on black ice and you're going to lose control. Downshift in what 75% of the users here would consider "slippery", and you'll be fine (i.e. 1/4 inch of snow in North Carolina is enough to throw people into a panic; the people in western NY and other areas that need a foot of snow and -20 wind chill factors before they consider closing schools laugh and continue moving at the speed limit, and don't do idiotic things which cause them to lose control.)

 

[Rubycon]

Originally posted by: thetxstang
Here's a myth I learned of recently: I'd always heard that running your car on Max A/C was harder on your cooling system than running it in Normal A/C mode. An automotive A/C technician that I know and trust recently explained that this is not the case at all.

Evidently, when running your car in Normal A/C mode, outside air is allowed to blow over the evaporator core, which, since the outside air is usually much warmer, makes it harder for the evaporator core to cool and do its job. Conversely, when your A/C is set to Max, the air is set to recirculate mode, using the already cooled cabin air to blow over the evaporator core.

He also said the following method is the best way to cool the inside of your car on a hot summer day: Use the Normal A/C setting for the first couple of minutes or so, then set your system to Max A/C. Maximum cooling and the most efficiency, FTW!

If a sensor was placed behind the evaporator, a simple controller could modulate the outside air damper (using an electrohydraulic actuator or EHA rather than the conventional vacuum actuator to prevent excessive engine vacuum loading) to provide optimal evaporator return air temperature.

 

[her209]

Use anti-freeze during the winter and anti-boil during the summer.

 

[BD2003]

Originally posted by: thetxstang
Here's a myth I learned of recently: I'd always heard that running your car on Max A/C was harder on your cooling system than running it in Normal A/C mode. An automotive A/C technician that I know and trust recently explained that this is not the case at all.

Evidently, when running your car in Normal A/C mode, outside air is allowed to blow over the evaporator core, which, since the outside air is usually much warmer, makes it harder for the evaporator core to cool and do its job. Conversely, when your A/C is set to Max, the air is set to recirculate mode, using the already cooled cabin air to blow over the evaporator core.

He also said the following method is the best way to cool the inside of your car on a hot summer day: Use the Normal A/C setting for the first couple of minutes or so, then set your system to Max A/C. Maximum cooling and the most efficiency, FTW!

That would depend on your car...the recirculation is completely mechanical on mine. Closing the vent definitely cools down quicker. Heats up quicker too, but then you get all foggy.

 

[exdeath]

Originally posted by: MS Dawn

Originally posted by: thetxstang
Here's a myth I learned of recently: I'd always heard that running your car on Max A/C was harder on your cooling system than running it in Normal A/C mode. An automotive A/C technician that I know and trust recently explained that this is not the case at all.

Evidently, when running your car in Normal A/C mode, outside air is allowed to blow over the evaporator core, which, since the outside air is usually much warmer, makes it harder for the evaporator core to cool and do its job. Conversely, when your A/C is set to Max, the air is set to recirculate mode, using the already cooled cabin air to blow over the evaporator core.

He also said the following method is the best way to cool the inside of your car on a hot summer day: Use the Normal A/C setting for the first couple of minutes or so, then set your system to Max A/C. Maximum cooling and the most efficiency, FTW!

If a sensor was placed behind the evaporator, a simple controller could modulate the outside air damper (using an electrohydraulic actuator or EHA rather than the conventional vacuum actuator to prevent excessive engine vacuum loading) to provide optimal evaporator return air temperature.

ack! more $3 sensors that take 5 hours to replace...

 

[her209]

You get better gas mileage when using higher octane gasoline since you get more "ummph" for the same volume of gasoline.

 

[exdeath]

Originally posted by: her209
You get better gas mileage when using higher octane gasoline since you get more "ummph" for the same volume of gasoline.

This is somewhat true... though to what extent is questionable.

Using a gasoline with higher knock resistance allows more timing which produces optimal power out of a given volume of mixture, which should in turn require less slightly less throttle application to achieve the desired power level.

Also, in addition to retarding timing, some systems inject additional fuel to richen the mixture to cool combustion temperature in an effort to control detonation. This is wasted fuel that is used only to absorb heat and is burnt up in the exhaust system.

You will always get better efficiency (mpg) and power using the fuel the engine was designed for. Increasing octane will simply give you the full advertised power and mpg you were missing out on all along if you were using a lower octane fuel than what was recommended by the manufacturer. Increasing the octane beyond the factory recommendation, however, will result in no benefits unless the ignition maps and/or compression ratio of the engine are modified to take advantage of it.

 

[Evadman]

Originally posted by: Vic
AWD/4WD helps you brake in slippery conditions.

AWD? Agreed. Doesn't help worth a damn. However, I have to disagree with you on a 4WD vehicle. I can stop quite a bit faster with a center locked differential, and even faster with a front and rear locker.

That is because the center differential will not allow a wheel to lock, only all 4 of them. That means you will get absolute maximum breaking force before sliding as the force is applied across all 4 wheels.

If you have a 4 wheel drive vehicle with a locked or chain driven transfer case you can easily see for yourself. Go out in a slick surface and leave the vehicle in AWD or 2WD. Get mocing and pull the emergency breake hard enough so the rear wheels lock. Note how fast you are going. Now, lock the transfer case (or shift into 4WD) get going, and pull the ebrake. I seriously doubt you would have the strength to lock the wheels, and you will stop a hell of a lot quicker.

Without axle lockers, you would have to lock one front and one rear wheel. You can't lock both front or both rear unless you lock all 4 as the front and rear driveshafts are locked together. That means any uneven braking force will be applied through the drive shafts to the wheel with the most traction. In other words thus giving you the optimal friction surface.

In other words, in a standard braking system, the front does about 70% of the braking force, and the rear 30%. But what if the front only has 10% of the traction and the rear 90%? With a locked transfer case, the rear can do more work than the proporting valve would normaly allow. Go ahead, try it.

 

[DrPizza]

Originally posted by: Citrix

Originally posted by: Zenmervolt
Post some of the most persistant automotive repair myths that you've seen or heard, preferably things that can apply to any car and aren't model specific.

Some of my own favorites:

1) If the lights come on, the battery has to be good, so it's not worth testing it with a multi-meter.

2) Nitrogen in your tires will give you a smoother ride.

3) Blue tinted bulbs help you see better.

4) If you have keyless entry and you lock your keys in the car, you can call a friend on your cell and have them use the spare remote to unlock your car if they point the remote at their phone and if you put your cell phone near the car.
Other entries?

ZV

I remember hearing about that a month or so ago on the radio and i think the host actually got it to work. ill have to try it on my car.

Let us know how it turns out.
But, I'll save you the trouble: snopes
That must be one heck of a cell phone if it can listen to a radio frequency on a typical microphone and play back RF via its speaker