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When the car is idling, I can hear a "puffing" sound coming from under the hood. My thinking is that it is an exhaust gasket. I'm not getting any codes from it, just this noise. It sounds like a ticking or like air escaping. It changes with RPM. It's not loud enough to notice when driving, so seems like a minor leak. I thought about the air pump hoses, but I have replaced those, and I believe it is a constant pressure, so would sound more like air escaping a balloon than this does.
Any other thoughts? Also, engine noise level seems normal... it's not louder than usual or anything. Runs great!
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BMW CCA Member
I think you have pretty much nailed it. To further diagnose, you can try slowly moving a tissue around the area to see where the blow is coming from. You will probably have to disable the fan for this to work.Originally Posted by SounderMN
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Chris
NASA GTS2
Member
I would check the Secondary Air Pump Solenoid on the exhaust manifold. They fail pretty often and when they do, they allow hot exhaust gas to enter the Secondary Air Pump, destroying it.
It could also be a CCV problem. There are various ways to check that if you do a search.
It could also be the famous VANOS rattle, which is harmless. That sound would come from VANOS solenoid at the top front of the engine. There are some YouTube videos of the VANOS rattle that you can use for reference.
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Your spark plugs are loose.
~Mike
Member
Exactly what I was going to say. I've seen this several times.
96 320i Touring
98 Z3 2.8 Roadster
01 PY M Coupe
96 Z3 1.9 - DASC
95 318ti Clubsport
94 Miata M-Edition
13 smart fortwo
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Okay, guys. Loose plug? That cant be it, I'm thinking... the car would run badly. But, worth a look. Guess what... one of the plugs was loose. You guys saved me a ton of work that would have done nothing! Thanks! :-) I love this forum!
Member
Always glad to help. I was once in your shoes too.
Let me guess, you have Bosch plugs?
~Mike
Member
Many years ago I stopped to help someone that had broken down in a Mini (the original ones). I was very surprised to open the bonnet and discover that one of the plugs had come completely out and was flapping around on the end of the HT lead!
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I don't know if they are Bosch. Is that common with Bosch plugs?
Member
To my understanding, yes.
~Mike
Member
The same thing happened to me a few months after changing plugs with new Bosch ones. I use a torque wrench on everything so I was a bit shocked when it happened.
Sim Simma
Moderator
If it puffs more than twice you need to kindly remind it that its time to pass it on.
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No Bogarts allowed. :-)
Kidding aside, I have never heard of plugs getting loose like this. At least it's an easy fix, and I was smart enough to ask people smarter than me. HeliHover and Tim identified it right away... it would have taken me forever to figure it out. It's just a very strange thing, and I will know what it is next time for sure!
If it does happen again, I'll be changing out those plugs for something different.
Sim Simma
Moderator
Make sure not to use anti-seize
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This might have been my problem. The arguments for and against anti-seize are equally loud and prevalent on the interweb. Not being able to tell the good advice from the noise, I opted for a small amount in hopes it would prevent the plugs from getting fused to the head. I don't know how many miles later the plug loosened up, but it was probably about 3k given my normal driving amount.
Member
Spark plugs are fine. A Youtube video shows a (clicking sound) when a plug is loose.
Member
?
If you read the thread you'll see that the plugs were loose, but thanks for the input.
Member
I might as well add to this, since it came back up. I was sure I needed a head gasket. it was "Puffing" as said here, no "clicking". Did all the checking, listening, reading, etc. Then someone suggested loose spark plugs. That was it, problem solved with ease. I had installed them, probably afraid to strip the threads, because I had done that on a motorcycle head once. So, not too tight, and not too loose.......
Member
A friend with a 330i had the same issue FWIW. Loud clicking/puffing from cyl6. We feared the worst, but it turns out the spark plug was loose!
Member
There's a tightening spec on the box and I recommend it be adhered to. If you DIY them, go back a week or so later and check them (yes, takes a few minutes, depending on model, but can avoid a problem...). If you paid to have them done, and are comfortable checking them a week/a month later, do so. Just do not over tighten them__use a quality torque wrench__and do them with the engine cold.
Left uncorrected, like on an overnight drive from Virginia to Ohio, a loose spark plug CAN CAUSE DAMAGE. When #5 was blown completely out out of the threads, and left to continue arcing for hundreds of miles, the damage and resultant repair isn't slight.
Had to pull the head on this 2.8 to effect a repair; top sealing surface for #5 plug required spot-facing to save the head, along with a thread repair insert.
Surface was only cut deep enough to get smooth/flat seal, but that still allowed the plug to protrude too far into combustion chamber...
... requiring the use of >.070" worth of sparkplug indexing washers!
So, CHECK those plugs!
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