Slightly random popping when pulling to a stop when cold outside

[Chicagospeed996]

So it's weird. I will drive and get the engine up to temperature. I will idle at a stop light and about 15 seconds later a slight pop occurs. Then a couple seconds later another pop. The pops are of different volume and seem to come from different places in or outside the car. I can't duplicate it when I pull into my garage to listen. Any clue?? Seems to only be present when the temp is below 50F or only time that I noticed?

Engine and exhaust are good. Plugs are new, just changed. Could are good. No misfiring. Doesn't sound like a misfire and is random and seems to possibly be cold contraction of body panels?

[Loren]

Check for fault codes?

Just guessing without them.

[Chicagospeed996]

No CEL. I don't think it's the engine at all.

[Chicagospeed996]

0 codes when read with a generic OBDII scanner

[Chicagospeed996]

I am thinking it might be thermal expansion as the car warms up and the hot coolant starts flowing to the cold 40 degree piping and radiators. I took a video and I will see if it is discernible and can post it.

[White987S]

Who's your indy shop in the Chicago area? Fischer Motors in Lake Barrington would be good for you. FYI.

[Chicagospeed996]

Typically I do my all my own work, but might be an option. It doesn't sound serious, but it is odd and random it seems.

[Chicagospeed996]

https://vimeo.com/111216115. Here it is. I highlight just after the pop. Seems to come from the front of the car possibly but cabins can play tricks on the direction of the sound.

[Chicagospeed996]

FYI, just changed oil 100 miles ago, no metal. I*S changed 3,500 miles ago incase people jumped right in that.

Edited November 7, 2014 by Chicagospeed996

[Chicagospeed996]

Possibly the windshield popping?

[Chicagospeed996]

More info. Only occurs as the vehicle is coming up to temperature. Cold doesn't happen and completely warm it doesn't happen. This is leading me to believe some thermal expansion issue.

[MARTINIRACING74]

Hello I have a 2000, 996 with 127,000 miles on it, and I hear that popping sound as well. I never got a cel light too, and it sounds like it comes from all different sides. I also have a 1998, 986 with similiar miles but I never hear a popping sound in that one. I guess it only comes from 996s, if I was you I would not be to worried about it as long as your engine or suspension is not the cause of the sound. My reasoning from that judgement is, it has made that sound in my vehicle since I bought it at 89,000 in 2012. I have had many services completed on it and the popping sound is still there and will do it randomnly and sound will very as well.

[Chicagospeed996]

Thanks Martini. That's what I was thinking too. Sounds like heat rising at stop lights and causing some plastic or metal popping from expansion.