Does E46 3-series have 'lifters' in the engine?

[William330]

Seems while accelerating sometimes I hear what sounds like
engine lifters ("pinging"?) rattling. It's very low sound, and just
started.

The car is never abused, and only has 15,000 miles.

The oil was changed recently, I wonder if they screwed something
up?

I checked the oil level, and the dipstick showed oil at the middle
of the 'normal' range while the engine was still hot. However, the
oil wasn't clear in color, and smelled slightly burned up. Is that
color/smell normal?

 

[Big Daddy]

Yes the car has hydrolic lifters, and unless you are over reving the engine they make very little noise, worst case a tick tick sound! If your oil smells burnt you need to have it changed.

 

[Kirby]

The rattling noise could be pinging, technically called preignition. Pinging is not the valves rattling. It is uncontrolled ignition of the fuel in the cylinder, usually caused by low fuel octane or just bad fuel.

What octane rating are you using? Run it almost empty, and fill it with 92 - 94 octane. If the noise stops, you have your answer.

 

[William330]

Hmm, could it be dirty fuel injectors?

I recently tried Exxon gas, because I have some coupons. I've
never put in lower than 92 octane fuel since owning the car.

Just added fuel injector cleaner fluid, so maybe that will help.

It only seems to happen while accelerating as the car hits
about 35 MPH.

 

[William330]

Finally brought the car into the dealer, and they said the
noise wasn't coming from the engine, but was from a
"valve" in the muffler.

I'm not sure I agree, but it's under warranty, and if the
noise continues, they'll have to fix it anyway.

The ping noise occurs at about 1,700 RPM, and at no
other time.

I'll let you folks know how it goes.

 

[William330]

Well, the dealer installed a new muffler to address the "ticking" at 1,700 RPM problem.

The noise is slightly quiter, but I'm not sure they fixed the problem, but instead hid the problem by 'muffling' it. Should an engine make a ticking noise at a specific RPM?

The muffler has a valve on the right-hand exhaust tip, which I don't recall seeing there before. Is this stock, or is it an aftermarket recall part? Attached to the right-hand exhaust tip is some mechanical thing, which apparently opens and closes the valve (presumably at different engine speeds).

Haven't had time to mess with the car, but during a quick test drive could hear the same problem as before, but a little quiter.

My main concern is that the engine has some lifter problem, and I want that fixed while still under warranty.

I'm also going to try a different brand of gasoline, just to take that cause out of the equation.

 

[William330]

OK, wanted to update this with a resolution.

Kirby was correct. While I have always used 93 or higher
octane fuel, apparently gas stations are diluting gas to make
a few extra bucks and gouge consumers even more.

The junk gas was from a local Exxon dealer (nice, well maintained
station) for which I had $100 in gas coupons.

Anyway, after going back to Shell 93 octane fuel the sound started
to go away. I also added a bottle of STP Octane Boost ($4) for
good measure. The ping sound is pretty much gone and after the
second tank I expect it to be 100% gone.

So the whole muffler change was a waste, and the dealer should
have known better.

I may report that Exxon dealer for selling junk gas. The BMW dealer
said they have actually tested fuel from a car's gas tank that was giving
them grief, and it was well below the octane advertised to the customer.

Anyway, just wanted to update with the solution.