Full tank of gas for alignment?

[CharBaby]

Mazda in my signature is going in for an alignment tomorrow(I replaced a control arm). The tank is between 1/2 & 1/4. Should I fill the tank on the way?

The shop doing the alignment says it doesn't matter! But, I have heard different on many occasions! Some say 1/2 tank, some say FULL tank and other say it doesn't matter.

What say you?

CB

 

[Eddie]

I would say ~ 1/2 +/- 1/4

 

[Eddie]

I would say ~ 1/2 +/- 1/4. Probably more important to have a normal weight in the vehicle like you & ?. I suspect it make little difference anyway.

 

[old1]

It is only going to affect the caster reading, and then only very minutely. I say don't worry about it, but if anything, approximately 1/2 tank would be most ideal, as that would give you an average amount of rear weight. Unless you usually keep the tank nearly full or nearly empty. But as I said before I wouldn't even think about it.

 

[Turk]

5/8ths.

 

[Wolf359]

Gas weighs a little over 6 pounds per gallon. You have a 14.5 gallon tank. When they do the the alignment, you're not even in the car. I wouldn't think it'd be anything to worry about. The difference between half and full is about 42 pounds.

 

[Quattro Pete]

Originally Posted By: Wolf359
Gas weighs a little over 6 pounds per gallon. You have a 14.5 gallon tank. When they do the the alignment, you're not even in the car. I wouldn't think it'd be anything to worry about.

FYI, when performing alignment, BMW recommends full tank of gas plus extra weight blocks placed inside the car and in the trunk. Whether it actually makes a noticeable difference, I don't know, but that is their SOP.

 

[HTSS_TR]

Doesn't matter at all.

Sometimes you drive alone, other times there are another passenger or two or three. Each person can weight as much as 150 lbs or more. The car can handle different weights all the time.

 

[The Critic]

Originally Posted By: Quattro Pete
Originally Posted By: Wolf359
Gas weighs a little over 6 pounds per gallon. You have a 14.5 gallon tank. When they do the the alignment, you're not even in the car. I wouldn't think it'd be anything to worry about.

FYI, when performing alignment, BMW recommends full tank of gas plus extra weight blocks placed inside the car and in the trunk. Whether it actually makes a noticeable difference, I don't know, but that is their SOP.


+1.
I always align with a full tank.

 

[SumpChump]

Have it done in a full tank.

Also consider having it done loaded (with driver or mechanic & any heavy stuff you may carry DAILY) as it would be daily.

For example my '13 Camry SE runs daily with a just driver at 250lbs.

The shop did a comparison of the driver's effect on allignment out of curiosity sake prior to doing the allignment work. And it does affect it.

Here's the effect of the driver (bottom)


And just to be thorough ...here's the allignment results before and after the work. Obviously though the above image is more useful to your original post.

 

[zzyzzx]

It's whatever the Factory Service Manual recommends for your car. Last time I checked, I think it said gas tank 1/2 full and some weight for the driver.

 

[CharBaby]

Thank you all!

 

[SteveSRT8]

Weight and where it is located has a huge effect on alignment in most vehicles.

Our trucks are always aligned at full loaded weight with 110 gallons of water on board and all tools, equipment, supplies, etc.

 

[SumpChump]

Originally Posted By: Char Baby
Thank you all!


And don't let them talk you out of it. The good but, younger, tech I had tried to blow it off but a fella who has worked there forever came buy and said , "Let's do it" and this we did the test with it driver loaded. I got lucky he walked by.

 

[ISO55000]

Just an old guy’s opinion

I did car work and alignment in the mid-late 70’s and we were taught back then that the weight and distribution should match actual conditions. From memory though with those old analog hunters and the mass of those cars back then I cannot recall a situation where it made a difference.

However, with today’s digital equipment and different mass and construction of a vehicle, I can easily see where it could make a difference between the static and dynamic alignments. I doubt seriously if it would be a significant or damaging difference because if it was I would think all shops would require it as well as training schools, tire manufacturers etc.

I would believe that manufacturers would also not design an alignment spec that was that essential or critical for weight when they know 90+ % of the people owning cars will not maintain them properly. They might tell you that you should but I don’t think they would take the risk of liability if you didn’t.

From the simple engineering perspective I agree you should mimic all nominal conditions for an alignment (and tire pressure check) because even physics says there must be an effect but from the practical and experience side I don’t think you will significantly affect anything if you didn’t.

That said, I would not however apply that above observation and opinion to service trucks or any type of payload bearing vehicle but that’s beyond the normal limits of the average passenger car.

 

[demarpaint]

I usually do it with a full tank, and make sure the tires are properly inflated. You'd be amazed how many so called alignment experts don't check the tire pressure.

 

[GenesisGuy70]

I've had many alignments done (I buy a lifetime package, so I get it done regularly) and I have never once given any thought to the weight.

Interesting discussion.

 

[Gokhan]

Originally Posted By: Eddie
I would say ~ 1/2 +/- 1/4

Ditto. Especially the +/- 1/4 part.

 

[OneEyeJack]

If you can get the mechanic interested then do the alignment with say a quarter tank and then re-check it with a full tank. Maybe try it with a weight in the driver's seat as well.

 

[jc1112]

When i had my mazda in for alignment they said it didn't matter.

when i look at the factory service manual it states that there are different
goals for the camber , caster, and steering angle inclination based on the fuel
tank level.