87 vs 92 Octane Gasoline

[wayliff]

I brought my 2001 Chrysler Town & Country to the dealer because the engine had a pretty loud ping.

First time they replaced the AC compressor and told me the problem would go away.
Well...the problem was still there.

Second time they told me I should use 92 octane gasoline for two full tanks in order to remove the carbon buildup in my engine, then I could go back to 87 octanes.

The manual says that the recommended gasoline for this engine should be 87 octanes.

While researching on the internet I found that using 92 octane gasoline could actually harm my engine.
Premium Gasoline
Certain high performance engines benefit from use of high octane fuel. For other engines, using a fuel with a higher octane rating than the vehicle requires sends unburned fuel into the emissions system and catalytic converter. This puts unecessary stress on the emissions system. For some vehicles, a rotten egg smell coming from the tailpipe signals use of too-high octane gas.

Also found that all gasolines should have the same detergents and cleaning agents to clean your engine, so one should not have to switch to clean the engine.
Regular Unleaded Gasoline
The recommended gasoline for most cars is regular 87 octane. One common misconception is that higher octane gasoline contains more cleaning additives than lower octane gas. All octane grades of all brands of gasoline contain engine cleaning detergent additives to protect against engine deposit build-up. In fact, using a gasoline with too high of an octane rating may cause damage to the emissions system.


Would anyone have a clue on the following?

1. Why would the dealer tell me to do this?
2. Why are considered high quality 87 octane gasoline distributors?

Thanks for your help.

In the meantime the van has the first tank of 92 octane gasoline and it is going quite faster than the regular one. No ping heard though.

 

[Shawn]

Use the lowest octane the car runs without pinging.

 

[ElFenix]

Originally posted by: wayliff
I brought my 2001 Chrysler Town & Country to the dealer because the engine had a pretty loud ping.

First time they replaced the AC compressor and told me the problem would go away.
Well...the problem was still there.

Second time they told me I should use 92 octane gasoline for two full tanks in order to remove the carbon buildup in my engine, then I could go back to 87 octanes.

The manual says that the recommended gasoline for this engine should be 87 octanes.

While researching on the internet I found that using 92 octane gasoline could actually harm my engine.
Premium Gasoline
Certain high performance engines benefit from use of high octane fuel. For other engines, using a fuel with a higher octane rating than the vehicle requires sends unburned fuel into the emissions system and catalytic converter. This puts unecessary stress on the emissions system. For some vehicles, a rotten egg smell coming from the tailpipe signals use of too-high octane gas.

Also found that all gasolines should have the same detergents and cleaning agents to clean your engine, so one should not have to switch to clean the engine.
Regular Unleaded Gasoline
The recommended gasoline for most cars is regular 87 octane. One common misconception is that higher octane gasoline contains more cleaning additives than lower octane gas. All octane grades of all brands of gasoline contain engine cleaning detergent additives to protect against engine deposit build-up. In fact, using a gasoline with too high of an octane rating may cause damage to the emissions system.


Would anyone have a clue on the following?

1. Why would the dealer tell me to do this?
2. Why are considered high quality 87 octane gasoline distributors?

Thanks for your help.

In the meantime the van has the first tank of 92 octane gasoline and it is going quite faster than the regular one. No ping heard though.

because dealers are asshole pricks that don't want to fix your car when it is under warranty. they make much more money taking your car later. :|

but, that article is wrong, chevron's premium blend has more techron in it than the regular. and the really cheap grocery store gas probably doesn't have any additives.

 

[NutBucket]

Your dealer is full of it. You should only need high/higher octane because of two things:

1.) Car was designed for it

2.) Your car isn't running right (pinging).

In other words, dealer doesn't want to admit your car is broke and fix it under warranty.

 

[ElFenix]

Originally posted by: NutBucket
Your dealer is full of it. You should only need high/higher octane because of two things:

1.) Car was designed for it

2.) Your car isn't running right (pinging).

In other words, dealer doesn't want to admit your car is broke and fix it under warranty.

mine did the same. guy said to me that 'well, your car started just fine every time we had it'... of course he was standing right there when the car refused to start as soon as i got in it. he also said 'your manual says you can run 87, but you'll get better performance from 89 or 93' which is BS, the manual does not say that, i've read that multiple times.

 

[wayliff]

Can the 87 octane gasoline give my engine carbon build up?

 

[TheLonelyPhoenix]

Filling up on premium a couple times won't kill your catalytic converter or anything. Using a higher-rated fuel than what's required definitely won't burn as cleanly and has a negative impact on your gas mileage, but that shouldn't be an issue over just a few hundred miles.

Higher-octane gasolines generally have a higher detergency level than regular 87 octanes, which is probably why they want you to use that. I seem to recall that simply driving harder than usual and redlining a few times also helps burn off carbon deposits, but I'm not 100% of that... maybe one of the car guys here can comment of that for you.

 

[cyclohexane]

high octane gas only prevents engine knocking, which you shouldn't have in the first place unless you have a sh1tty car

 

[iamwiz82]

Originally posted by: NutBucket
Your dealer is full of it. You should only need high/higher octane because of two things:

1.) Car was designed for it

2.) Your car isn't running right (pinging).

In other words, dealer doesn't want to admit your car is broke and fix it under warranty.

Pinging can be caused by carbon buildup. Higher octane gas will eliminate the pinging, but it won't clean the engine.

 

[wayliff]

I just found this info from the FTC on gasoline.

http://www.ftc.gov/bcp/conline/pubs/autos/octane.htm

Will higher octane gasoline clean your engine better?
As a rule, high octane gasoline does not outperform regular octane in preventing engine deposits from forming, in removing them, or in cleaning your car's engine. In fact, the U.S. Environmental Protection Agency requires that all octane grades of all brands of gasoline contain engine cleaning detergent additives to protect against the build-up of harmful levels of engine deposits during the expected life of your car.

 

[NutBucket]

Originally posted by: wayliff
Can the 87 octane gasoline give my engine carbon build up?

Shouldn't.

 

[wayliff]

All the dealer wants is to get paid a stupid diagnostic fee to tell me that I have to put better gas...why did not they do that in the first place?!

 

[FrustratedUser]

Originally posted by: iamwiz82

Originally posted by: NutBucket
Your dealer is full of it. You should only need high/higher octane because of two things:

1.) Car was designed for it

2.) Your car isn't running right (pinging).

In other words, dealer doesn't want to admit your car is broke and fix it under warranty.

Pinging can be caused by carbon buildup. Higher octane gas will eliminate the pinging, but it won't clean the engine.

True

 

[wayliff]

Originally posted by: NutBucket

Originally posted by: wayliff
Can the 87 octane gasoline give my engine carbon build up?

Shouldn't.

What causes the Carbon build up?

 

[FrustratedUser]

Originally posted by: wayliff

Originally posted by: NutBucket

Originally posted by: wayliff
Can the 87 octane gasoline give my engine carbon build up?

Shouldn't.

What causes the Carbon build up?

All gas will cause carbon buildup over time. That together with burned oil.

 

[wayliff]

is one gasoline better than the other? say Chevron vs Shell or Texaco vs Mobil or BP vs Sunoco
I would definitely go for the better gasoline.

 

[smithdj]

Running 92 or even 93 (where available) will not fix the problem. The only "quick" okay not too expensive possible fix is to have the intake manifold clean which will clean the carbon deposits off of the valves and the tops of the pistons. The dealer should not be a cheap a$$ and do it for you. They hook a bottle full of cleaner stuff (cant remember the brand) to the intake via a vacuum line and let it burn through the engine, it takes about 20 minutes. The bad side, where do you think all of that crap goes? Right down the sides of the pistons Seriously, have them do this, if not for free, it should cost $40

 

[Zenmervolt]

Originally posted by: ElFenix
but, that article is wrong, chevron's premium blend has more techron in it than the regular. and the really cheap grocery store gas probably doesn't have any additives.

All gasolines have a certain minimum detergency level. Bargain fuel has the bare minimum. Name brand has more. And name brand Premium has up to three times the detergents of name brand regular. I know that Shell's Premium has significantly more detergents than their regular or plus.

That said, Premium fuel is NOT a way to clean out an already dirty fuel system. You need to use a concentrated cleaner. Chevron's Techron cleaner can be found in many auto parts stores and will be better at cleaning out an already dirty fuel system.

ZV

 

[wayliff]

so what happens when the carbon goes down the sides of the pistons?

 

[iamwiz82]

Originally posted by: smithdj
Running 92 or even 93 (where available) will not fix the problem. The only "quick" okay not too expensive possible fix is to have the intake manifold clean which will clean the carbon deposits off of the valves and the tops of the pistons. The dealer should not be a cheap a$$ and do it for you. They hook a bottle full of cleaner stuff (cant remember the brand) to the intake via a vacuum line and let it burn through the engine, it takes about 20 minutes. The bad side, where do you think all of that crap goes? Right down the sides of the pistons Seriously, have them do this, if not for free, it should cost $40

Yes, Mopar makes a product called Combustion Chamber Cleaner/Conditioner. Have them run a couple of cans through your engine. It'll smoke like mad, but it works.

 

[NutBucket]

Seafoam? Isn't that suppose to remove those deposits?

And yes, supposedly while all brands meet the minimum there are differences between them. So say people I know who work for Chevron and my experience buying cheap Arco gas vs. my usual 76.

 

[FrustratedUser]

Originally posted by: wayliff
so what happens when the carbon goes down the sides of the pistons?

Hopefully most of it will escape through the exhaust. Some get trapped in the oil film and will cause wear.

 

[freebee]

Gasoline is basically the same as far as brands go. the 3.8 in the t&c will run fine on regular. Bottle of fuel injector cleaner may help, get the good stuff.. bg44k, etc. usually 16 bucks or so.

 

[iamwiz82]

Originally posted by: FrustratedUser

Originally posted by: wayliff
so what happens when the carbon goes down the sides of the pistons?

Hopefully most of it will escape through the exhaust. Some get trapped in the oil film and will cause wear.

This is why you should do an oil change shortly after a cleaning. Otherwise that carbon will sit there and could block up the oil pump or other nasties.

 

[wayliff]

Originally posted by: iamwiz82

Originally posted by: smithdj
Running 92 or even 93 (where available) will not fix the problem. The only "quick" okay not too expensive possible fix is to have the intake manifold clean which will clean the carbon deposits off of the valves and the tops of the pistons. The dealer should not be a cheap a$$ and do it for you. They hook a bottle full of cleaner stuff (cant remember the brand) to the intake via a vacuum line and let it burn through the engine, it takes about 20 minutes. The bad side, where do you think all of that crap goes? Right down the sides of the pistons Seriously, have them do this, if not for free, it should cost $40

Yes, Mopar makes a product called Combustion Chamber Cleaner/Conditioner. Have them run a couple of cans through your engine. It'll smoke like mad, but it works.

I will definitely be asking about this procedure.