--fuel system cleaner

i was changing my engine oil from valvorine, and one of the technitian recommended a fuel system cleaning service. the product they carry was "run-rite." supposely it clean fuel injectors, air intake and emission system. does it worth it? i ran about 1,9000.

--tire rotation

i got my summer tire, direction, has ran about 3000 mil after the purchase, and when rotating the tire do i change front right to rear right, and front left to rear left? seems like the subaru manual says the same thing, yet this technitian from valvorine says to cross ( front right to left rear, front left to right rear.) i don't know which one is true.

thanks,

For the fuel system, I wouldn't use a professional service at 19,000 mi. If you are worried about your system, there are off the shelf cleaners you can dump into your gas tank when you fill up that should keep everything good for a long time.

Tire rotation after 3,000 miles? Why? :confused:

Rotate tires like manual says. Right to right left to left.
Every 3000 seems excessive to me also. I do every 2 oil changes (6000 miles). I think Subie manual says every 7,500 miles. Someone straighten me out on that one if I'm wrong.

I think cross rotations is for non all wheel drive cars? Not sure on that one though.

i thought i had to change first two 3000 miles for the brand new summer tires, but i guess i got wrong infomation. thanks guys

Tire rotation info from Tire Rack:
http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=43

I use the "rearward cross" pattern on my STi:
http://www.tirerack.com/images/tires/tiretech/rotate1.gif

i stick with what the manual says ... front to back every 7500

Front to back is what the manual says, I'd trust it. Fuel system cleaner probably won't do poop with so few miles.

Just a thought on tyre rotation. Check they aren't directional tyres.
I know it's obvious to some but it's an easily missed point.
Personally, I never bother unless there is a major difference in wear. If the reason is because the tyres are wearing unevenly, you have an alignment problem.

John

I use a bottle of Chevron Techron Concentrate (the expensive stuff) every oil change (5k miles).

I rotate my tires every 4k miles. The more you rotate, the longer your tires will last. 3k miles is the shortest interval i'd follow, 7.5k is the longest i'd go. As long as your tires are NOT unidirectional (and you don't have different size tires on the front and back), you can rotate them to all four corners (yes you can do it with asymmetrical tires too). I personally do it the same way as shown above for my RE92s and Azenis Sports:

http://www.tirerack.com/images/tires/tiretech/rotate1.gif

However, if your tires ARE unidirectional, then you'll have to stick with just rotating them front-back (which is why i'll never buy unidirectonal tires). At the halfway point on the tires life you could go to a tire shop and having them take the tires off and remounting them the opposite way so you can swap sides, provided you're trying to make them last as long as possible.

The key is to keep the rotation intervals consistent and to follow the same rotation pattery EVERY SINGLE TIME. And don't forget to reset your tire pressures after rotation.

If I pay someone to rotate my tires every 4000 miles I'd soon have spent enough for a new set of tires. I do my own when the tread depth difference is 2-3/32 inch difference which falls within the factories "1/4 inch" maximum circumference and for my driving style and tires this occures about 7-9,000 miles. I have had the best long term results using tireracks/Michlie/Goodyears recomeded rear cross. ie rears to same side front and fronts crossed to rear.

Personally, I never bother unless there is a major difference in wear. If the reason is because the tyres are wearing unevenly, you have an alignment problem.

John

With 60% of the weight on the front tires, even a perfectly aligned car will have disproportionate wear on the front tires.

With 60% of the weight on the front tires, even a perfectly aligned car will have disproportionate wear on the front tires.

Correct. Because of the 'tire conicity' effect, your front tires will wear slightly faster than the rears, usually on the inside treads. So rotating your tires periodically will maintain even tread wear for all four tires, which would lead to a longer life.

With 60% of the weight on the front tires, even a perfectly aligned car will have disproportionate wear on the front tires.

Sorry, I meant about uneven wear across a tyre.

John

Sorry, I meant about uneven wear across a tyre.

John

Well if you don't rotate your tires, you'll get more wear on the inside treads than the outside treads. Are you talking about like having feathered wear on your tires? :confused:

Feathering usually only arrises when you have worn out components that allow the shifting of the contact patch's dynamic location with respect to the road. If you dont rotate or simply have toe or castor problems you will usually just have disproportionate wear.

So the general consensus is that fuel system cleaner works, eh? I thought that stuff was snake oil. I took apart a Bosch fuel injector once and it had a little tiny screen in it that collected debris, I assume this was the part in the injector that caused the most difficulty in the part after many miles. Unless the cleaner dissolves this stuff so it can be injected into cylinders then exhausted, the cleaner would not remove it and problems would continue. Comments?

I use a bottle of Chevron Techron Concentrate (the expensive stuff) every oil change (5k miles).

I rotate my tires every 4k miles. The more you rotate, the longer your tires will last. 3k miles is the shortest interval i'd follow, 7.5k is the longest i'd go. As long as your tires are NOT unidirectional (and you don't have different size tires on the front and back), you can rotate them to all four corners (yes you can do it with asymmetrical tires too). I personally do it the same way as shown above for my RE92s and Azenis Sports:

http://www.tirerack.com/images/tires/tiretech/rotate1.gif

However, if your tires ARE unidirectional, then you'll have to stick with just rotating them front-back (which is why i'll never buy unidirectonal tires). At the halfway point on the tires life you could go to a tire shop and having them take the tires off and remounting them the opposite way so you can swap sides, provided you're trying to make them last as long as possible.

The key is to keep the rotation intervals consistent and to follow the same rotation pattery EVERY SINGLE TIME. And don't forget to reset your tire pressures after rotation.

What he said!!!

Chevron Techron is great stuff. The oil change place is trying to clean your wallet not your fuel system. :rolleyes:

Just use seafoam, it's more fun! And you can use it in your oil, fuel, and engine.

BG fuel system cleaner. makes the car idle soooooo smooooooth. I was actually very amazed and had to stick my head out the window(while parked and idling) to see if the engine was running.

ive also used techron too but bg cleaner makes it idle better. smoooth

i stick with what the manual says ... front to back every 7500

This is the pattern subaru says (as per above):

http://www.scoobymods.com/forums/showthread.php?t=2786

A comment on tire rotation frequency. It depends on the tire's wear rating and life. For instance I currently have summer tires that I expect to get about 12-15K miles on them before they are worn out. So to keep the wear even I need to rotate them about every 3-4K miles. If I had 40,000 mile tires I could get the same even wear by rotating them every 8-10K miles.

So it all depends on what kind of tire you have, how you drive and what kind of tire life you expect.

If the tires are directional they will only spit water out if facing the right direction. That's why the owners manual says to keep them on the same side. If the tires aren't directional you can do them like tirerack says.