graffixnyc

Hey all,
The other day after I had returned home from picking my son up, I was in the garage and I heard my car make this sound. At first, it sounded like electronics frying/sparking but there was no odd smell or anything and everything seemed to be working fine. I turned the car on again for a few minutes and turned it off and it happened again after turning the car off for a minute or so. This time I thought it could be the sound of water hitting a hot part (which also kinda sounds like electric sparks). The AC was running, so I do think it's coming from that but It kinda freaked me out at first. I understand there will be condensation and I have read posts on other forums about a "sizzle" sound but I'm not sure it's the same thing I heard. I never heard that with my 2017 350. I do think it's liquid coming in contact with a hot part but I don't think it's normal. Has anyone heard this sound before?

Here is a video you can hear it twice between the 2 and 4 second mark.

oscarleo

Hard to tell from video, but sound seems to me to be the sound hot engines make after shut down and metal that had expanded from heat starts to contract.

graffixnyc

It's not that sound. I hear that sound a lot and is more like a ping of the metal contracting. This sounds like liquid is released from somewhere (nothing was on the ground under the car though) and it basically sounded like liquid hitting a really hot frying pan and sizzling.

I was trying to get a better video of it yesterday but it only did it a little that time and didn't come out on video. Today I have to drive for a while and it's a hot day so I'm going to try to get a video with the hood open. It just freaked me out at first because it does sort of sound like electronics frying/sparking. It wasn't until the 2nd time that I figured it was liquid hitting a hot part of the car causing it to sizzle.

stktyz33

It appears that these cars make "clicking" sounds when electronics wakes up / modules get energized. For instance, lock the car, let it sit for a few minutes, leave the key out of range, come back, touch the sensor area of the door/pull the handle. It won't open but it will make a series of "clicking" noises. Your sounds sound a bit louder and more metallic but the video can be distorting it.

graffixnyc

It's different from the clicking sound. I always hear the clicking sound and always thought that was just sensors and stuff shutting down etc. (This video is actually trimmed to focus on the sizzle sounds, the unedited video you can actually hear the clicks) This definitely sounds like when you first throw an egg on the frying pan.it seems to be coming from the engine compartment..

I'm really going to try to get a better video of it today when I go for a drive in a bit.

jkaetz

I'd be following the AC lines to see where condensation is dripping off. If it has a chance to drip on something hot it would most certainly boil/evaporate/sizzle.

2Ruf

I've got the same noise on my GLE 350.
I'm assuming that it's condensate from the AC dropping down onto an exhaust pipe

graffixnyc

I will take a better look. Yesterday and this AM I took the car out and had the AC blasting and it figures when I get home, pop the hood to see if I can record and see where it was coming from, it didn't do it. lol. I will try to check it again today when I pick my son up from camp later.

That's what I think it is, it seems like it's liquid that gets released after the car is shutdown and then comes in contact with a hot part. Although, It sounds more like it's coming from the engine compartment area more than the exhaust. I just never heard that ever in the years of driving my 2017 GLE(I would hear pings and stuff from the metal contracting but never heard this type of sizzle sound) and the night I first heard it , I actually thought it was electronics frying. After it happened the first time, I jumped in the car and turned it on just to make sure it wasn't something electrical frying and everything was working fine, I then shut it down and then got the video in the OP as I was just standing there waiting to see if it would happen again. In the video, that was the 2nd time it had happened. The first time, it seemed like it was a lot louder and longer as I'm guessing more condensation/liquid was released after the first time I shut it down. I didn't see any liquid on the ground under the car so it must be hitting a hot part and just evaporating. I really hope I can it happens when I have the hood open and I can pinpoint where the sound is coming from and what part the liquid is hitting.