Clingging Gargling Sound

[Edubbz60]

2003 M-45 The first 5 min of driving if I give it a little gas I here a clinging or gargling sound from underneth the engine. I have a brand new oil change,and i use 87 or 89 most of the time. I might use 93 like every 5 fill ups of reg.

[szh]

i use 87 or 89 most of the time.

There is one problem! Unfortunately, this is a false economy situation ... for most people, this saves about $10 to $20 a month - and hurts your engine in the long run. Please appreciate the intent with which this is said : if this amount of money is difficult for you to afford (and it can be for some people), then you are better off getting another car where using 87 will not be an issue.

Infiniti clearly specifies that the VK45 engine needs 91 (or higher). Yes, in theory, the engine electronics can compensate a bit for the reduced octane, but the end result is usually "silent" pinging and engine damage over time. Plus, any bad gas on a fill-up (can easily happen with some stations) and the compensation becomes impossible. Then you hear the pinging ... at this point, you are damaging your engine minutely and continuously.

Finally, if the rattling is fairly loud, you may also have carbon build-up - the VK engines are prone to this, if you don't push them hard occasionally. Using low octane gas doesn't help either.

My recommendations:

1. Start using at least 91 all the time (I would love to get 93 here in California - you have it and don't use it! Argh!). No ifs, ands or buts about this, really.

2. After filling up, and using, at least a tankful of 91 or 93, rev the engine hard a few times to see if you can burn off the carbon deposits. Keep it at high revs for a bit. There is a specific Infiniti TSB that talks about this.

3. If still a problem, try a session with BG-44K (instructions are available here in this forum in prior posts ... search is your friend! )

4. If still present, try one more session with BG-44K. (But, limit it to a total of two sessions every 3000 miles!)

5. if still present, go to an Infiniti or Nissan dealership and get a powered injector rail flush done (make sure that they don't just do a treatment with the Nissan equivalent of BG-44K - ask for the rail flush!).

6. Finally, whenever you do a rail flush or use BG-44K, you should replace the engine oil and filter after the engine is back to normal.

Good luck with this!

Z

[menlund19]

Very good explanation szhosain!

I always use at least 91 octane in my m35. I came from a 2002 maxima where I experimented with lower octane gasoline (even though it said to use premium) and the difference was amazing. My maxima ran like crap without premium gas and I would never knowingly fill my m35 tank with anything less than 91.

[Edubbz60]

Thank, I started using low octane about 4 months ago after reading an article in a car magazine. Stated high octane was a rip off. I'll go back to 93

[szh]

Very good explanation szhosain!

I always use at least 91 octane in my m35. I came from a 2002 maxima where I experimented with lower octane gasoline (even though it said to use premium) and the difference was amazing. My maxima ran like crap without premium gas and I would never knowingly fill my m35 tank with anything less than 91.

Although it is good to use 91 on an M35, but I would be less concerned about this gas issue on that model - the V-6 normal recommendation is indeed 87 per the manual. You might, in theory, see a slight increase in horsepower, but this will be mostly undetectable. My reason for doing 91 on an M35 would be to reduce the impact of bad gas, where it drops below 87 at some stations at some times of the year!

However, the M45 is another story entirely - it needs the 91 for sure.

Z

[szh]

Thank, I started using low octane about 4 months ago after reading an article in a car magazine. Stated high octane was a rip off. I'll go back to 93

Good Stuff™!

Z

[Andrew224]

Thank, I started using low octane about 4 months ago after reading an article in a car magazine. Stated high octane was a rip off. I'll go back to 93

If your engine was engineered to run on regular low octane then using high octane is a waste. If your engine was engineered to use high octane, it is NOT a waste. To expand on what Z said, engines that have high compression ratios need high octane fuel to prevent the fuel from not burning properly. Higher octane fuel is harder to ignite and therefore will only ignite from the spark from the spark plug, not just from pressure and heat. Basically, the fuel ignites prematurely or burns too fast or ignites in two places at the same time (all are bad). In any case, lower octane fuel will damage the engine. Engines with lower compression ratios do not put the fuel under as much pressure so the low octane fuel will not burn improperly.

Andrew

[menlund19]

Although it is good to use 91 on an M35, but I would be less concerned about this gas issue on that model - the V-6 normal recommendation is indeed 87 per the manual. You might, in theory, see a slight increase in horsepower, but this will be mostly undetectable. My reason for doing 91 on an M35 would be to reduce the impact of bad gas, where it drops below 87 at some stations at some times of the year!

However, the M45 is another story entirely - it needs the 91 for sure.

Z

Isn't the compression ratio for the M35 and M45 relatively similar? Why would the M45 require Premium gasoline, while the M35 would not?

Based on what I have read, I thought the M35 also suggested Premium, but I may be mistaken...

[szh]

Isn't the compression ratio for the M35 and M45 relatively similar?

Yes. 10.3 for M35 and 10.5 for the M45.

Why would the M45 require Premium gasoline, while the M35 would not?

No idea. Probably because Infiniti tuned the engine and ECU that way ...

Based on what I have read, I thought the M35 also suggested Premium, but I may be mistaken...

Suggest, yes, but require, no. It is in the Users Manual that way, as I recall.

Z

[Pashdut]

2003 M-45 The first 5 min of driving if I give it a little gas I here a clinging or gargling sound from underneth the engine. I have a brand new oil change,and i use 87 or 89 most of the time. I might use 93 like every 5 fill ups of reg.

Hey dubbz, I also have the same exact problem. I hear a gargeling noise coming from right behind the steering wheel area (i think). After reading all of Z's post in this thread, I still do not understand how this can happen to me because I have always put 91 and for the last few thousand miles I have switched to Synthetic or Synthetic blend, so I am dumbfounded as to the cause and more importantly, the fix. I rev'd the engine like Z said but nothing doing. I guess I will have to try BG-44k as mentioned here (zerothread?id=344678) by Z. My warranty ends next month, so I'm first going to take to the dealership to inspect then if they want to charge me, I'll tell them because Z said to try BG fools!

[qship96]

Sounds like low coolant level causing air to circulate with the coolant creating the gargling sound you hear coming from heater core area or lines= very common on old Q.

[szh]

If it is a watery liquid sound, then I agree, it is likely not pinging or carbon build-up - I have no clue about the coolant air issue!

But, it is in the slightest bit metallic sounding (pinging or "clingging" like mentioned in the title), then I think it is engine-related and is either bad gas or too low an octane or carbon build-up ...

Never hurts to do the BG-44K treatment though! Sparingly, of course ... no more than two sessions per 3000 miles or so.

Z

[Pashdut]

If it is a watery liquid sound, then I agree, it is likely not pinging or carbon build-up - I have no clue about the coolant air issue!

But, it is in the slightest bit metallic sounding (pinging or "clingging" like mentioned in the title), then I think it is engine-related and is either bad gas or too low an octane or carbon build-up ...

Never hurts to do the BG-44K treatment though! Sparingly, of course ... no more than two sessions per 3000 miles or so.

Z

Sounds like low coolant level causing air to circulate with the coolant creating the gargling sound you hear coming from heater core area or lines= very common on old Q.

Alright so I'll fill the radiator when the M gets cooler tonight. I'll let you know how it goes. Thanks.