Well after driving for the last 6 years with my car which requires premium, it's kinda habit. So today while filling up the Jeep I just tapped the premium button, didn't even notice till it was full. Oops, oh well.

Anyways, i noticed almost immediately that my engine was quieter. In terms of valve train noise. I have a slight tick being it has 170k miles on it, and nearly as soon as I started it back up it was noticeably quieter. Why would that be? I know higher octane has better resistance to knock or detonation but didn't think it would affect valve train noise?

On the subject, is there anything I can do to permanently reduce the noise? I use an oil stabilizer and high mileage synthetic oil already. It doesn't appear to leak or really burn any although I notice my oil pressure is around 10psi lower than what it should be.

 

i try to put midgrade in mine!

 

I run midgrade as well, the mpg increase offsets the extra cost. I'd give that a shot to start with, especially since premium already solved your problem.

 

premium does burn cleaner, therefore, reducing wear on engine parts by allowing them to operate smoother. Valves tick and knock due to friction and when that friction is removed or lessened, the noise is removed/lessened. couple options are:
1. run regular and add a fuel cleaner (lucas or gumout). granted, yes, you'll notice your engine running smoother, but that's it (no real mpg gain) and it gets expensive.
2. run premium. this is the best "easy way out" solution. it burns cleaner, giving you a smoother operating engine and slightly better mpg depending on your driving habits.
3. run midgrade and get a slightly smoother engine, and again slightly better mpg depending on driving habits.
4. Go all out. Pull the throttle body, intake manifild, and injectors and clean them all thoroughly. Put it all back together and run SeaFoam through the system. Make sure to do your gas and vacuum. Some people also add it to their oil, but I've never been one to trust this. I've only done the vacuum (through the brake booster) and adding it to my gas. Run the engine, revving it like crazy to get it all through the system (tons of white smoke will be billowing from your Jeep) until the white smoke stops. This cleans out all the carbon in your engine. From here on out, run midgrade. You'll notice an immense difference in the smoothness of your engine, which, will give you slightly better mpg. Just as long as you don't use the power you regained by cleaning your engine out i.e. liberal use of the gas pedal.

 

how long would it usually take to get the swafoam through the engine and stop smoking?

 

I ran half a can of seafoam through my crankcase.. the SECOND I started her up, I heard the normal tick tick tick go quieter.. I love seafoam.

 

Thought there was an understanding that just sipping seafoam through your back vacuum port (brake booster line) only allowed the back three ports to be cleaned, an using a small hose on the throttle body was the way to go? But on topic my jeep likes 93 octane don't really notice much except for hot days.

 

You just gotta be EXTREMELY careful when going through the TB. You can easily hydrolock your engine.

 

Thanks for the input Actually going with your 4th suggestion is probably what I'll be doing. I've got a catback exhaust on the way since my muffler has a hole. Going to be ordering a TB spacer and possibly having mine bored to match. In doing that I'll be cleaning out everything in there, new sensors and such and would seem a great time to do a full seafoam treatment. The first thing I did when I bought it was run some through the tank and about 250 miles before I changed the oil I ran some through there. You don't want to wait to long cause it can dislodge sludge and you don't want that recirculating through. Also when I changed my oil I used a quart of Lucas oil stabilizer which helped a bit to.

Do you mean putting a small hose in the TB itself? Or is there a vacuum line there to use? What about through the PCV system?

 

premium in anything more powerful than the lawnmower for me

i get an extra 6-7 mpg on premium so do the math and in the end premium will be your cheaper route to go

 

Really??? What kind of mileage do you get? On mine, that would equal 21-22 MPG. I guess individual results will vary.

Later,
Codfish

 

Crankcase is a no no.

Seafoam MSDS Lists: naphtha/IPA/paleoil

Seafoam is alcohol based and alcohol and oil don't get along too well, also it would be the first thing sucked up by the oil pump, and bearings hate low viscosity liquids.

 

Premium better than regular?.........the myths just keep on keepin' on. At only 8.8:1 compression for the XJ 4.0, a lawn mower probably has more. I'm still looking for valid info (not opinions) that says premium is better for, improves mileage, makes the engine quieter, even though the owners manual says regular is fine. Someone help me out here.

http://www.consumerenergycenter.org/...s_premium.html
http://www.cartalk.com/content/featu...questions.html
http://www.straightdope.com/columns/...nd-regular-gas
http://www.usatoday.com/money/autos/...emiumgas_x.htm
http://www.epinions.com/content_2346164356
http://www.edmunds.com/advice/fuelec...3/article.html
http://www.caranddriver.sg/features/...emium_-feature

http://www.cartalk.com/content/featu...ium/myths.html
http://www.associatedcontent.com/art...n_premium.html
http://en.wikipedia.org/wiki/Gasoline

 

I think the guys that see a mileage increase are seeing the effect of 100% petroleum gas instead of ethanol. Almost all "regular" gas has ethanol unless it's from a oil company. On the other hand a lot of midgrade and premium fuel is pure gas. That will give you 15% mileage.

About quieting the valve train? Hmmm. I'm not persuaded. Maybe you've had a bit of preignition that went away with the better fuel.

 

Premium will get a better detonation, which in turn will increase mpg and power..........minimally, MPG increase would realistically be around .007 more, power would not be noticeable.

Regular will be just as good as premium in a jeep, if you put premium in the only thing that will increase is the amount you spend on fuel.

Now on the other hand, Premium from Shell, Chevron, or Texaco can aid in engine cleaning over long periods of time. Shell V-Power(premium) has a additive called Vektron, its minimal, but over a course of a couple thousand miles it will run cleaner than brand x discount fuel. As for Chevron/Texaco, same dilemma.

Regular=Premium. Its a jeep, not a racecar.