I'm using low octane fuel recommended by manual, but there's always light ticking noise coming from the engine.

Would you recommend me to try higher octane fuel, and can there be any problem for my engine if I try high octane and then turn back to a low octane in case the ticking noise remains with high octane either? Or light ticking noise is normal?

 

Some valvetrain noise is heard in OHC engines. Higher octane would be used to get rid of "knock" Knock usually shows itself under higher load/throttle positions as the engine needs the higher octane to efficiently burn the fuel to create energy. Knock definitely shouldn't happen at idle.

I think most likely you are hearing valvetrain noise. Double check your oil levels. If you still think the noise is objectionable, I'd take it to your dealer and listen to other similarly equipped models on the lot for comparison.

 

In everything I have read about gasoline, switching to a higher octane wont hurt the engine in anyway. All gas is made basically the same way, with higher octane having more of an additive in it, also it may clean your engine better. I have recomendations about using the higher octane every oil change just to clean it out along with the new oil. same goes for oil, some people recommend using a synthetic every couple of oil changes to help clean everything out. hope this helps you out.

 

Be careful swithing from regular oils to synthetic and back again. Some oils on the market are parafin based (wax) Pennzoil and I believe Quaker State are two that come to mind. If you have been running these types of oils, they leave a thin coating of this wax on everything (lubricity molecules I think the marketing guys call it...) When you switch to synthetic, it will wash all of this out of your engine. Which sounds like a good thing, except that it will all go to your filter, promptly clog it up, drop your oil pressure to 0 and grenade your engine. My friend's mother had this happen on her Datsun 240Z (It now has a 302 V8 in it, soon to be swapped with a 520 hp 331 V8...)

I recommend using regular type oils (Valvoline or Mobil 1 seemed to perform the best in the testing I have seen) for the first 5,000 or so miles to allow everything to seat in (piston rings, etc.), then permanently switch over to synthetic if you want your engine's internals to last the longest.

There are some cleaning agents in some brands of premium (93), I run a tank about every 6,000 miles or so to keep the injectors clean. You can probably achieve the same benefit with the "pour in tank" type injector/fuel system cleaners on the market.

 

in regards to oil, what type is suggested by Mazda. I have the 4 cyl 2.0L engine in my car, i know the oil weight is 5w-20, but should we be using synthetic oil or pure oil. which one is actually better for the engine.

 

The noises your hearing is normal noise for a regular maintained mazda 6..what is the odometer reading?

Weather conditions could also play a bearing on how the engine sounds on a cold start up and during the warm up period.

Changing between octane levels in fuel is not a problem ...just try to keep a min of 87% octane...also remeber just because the pump says it is 87 percent there is also a possibility of you getting bad fuel.


Hope this helps

 

Thank you very much, now I'm sure about trying higher octane, and will do it as soon as my tank gets empty.

I just would like to make one thing clear for me, maybe I seem to be too pushy, but it's a serious matter for me.

I owe my mazda6 since May 2005 and it had 26000 miles, and regardless of the season (summer, winter), warm engine or cold, I always can hear the noise - only when car is idle. I took it to the dealership last fall; they said that there are no any foreign noises in the engine. According to the oil measure wire, the oil level is normal.

When I'm standing by the front side of the car I can clearly hear light noise: click, click, click.....only when the cat at idle, regardless cold or warm, and weather condition.

Maybe I'm just too anxious guy, and it should be taken easier. I know that you cannot determine the real reason reading my post, but could you please just tell me if this voice can be absolutely normal, and should I definitely try higher octane?

Thank you.

 

Dont worry to much about your mazda 6 ...there is also a possibility this noise has something to do with your a/c compressor...while you have the vehicle in "defrost mode/turned on to windshield or in fresh air mode" the a/c compressor cycles...this is normal for most of todays cars...not just mazda...it makes a distictive click click click noise.Also,fuel injectors make a click noise too when cycling


...hope this helps


Sure, use higher octane fuel--it burns better,adds power and cleans

if you hear your engine "pinging" thats a sign to increase octane levels.

 

I've been running with pennzoil..... but i dont want my engine to grenade if i switch over to a full synthetic. I have only done 2 oil changes in which have used pennzoil oil synthetic blend. Do you think I can safely switch over to another oil without having problems? Maybe I'll use mobile 1

 

switching from 100% synthetic back to regular lubricants is not recommend.