Strange "crunch" sound
04-20-18, 07:59 AM
#1
Lexus Fanatic
Thread Starter
Strange "crunch" sound
Hey all-
I've noticed sporadically I have a strange "crunch" sound that happens somewhere right after startup, and I noticed today it happened after it had been idling for 30-45 seconds or so. It sounds quite ugly. Doesn't happen often, maybe once every 10-15 startups.
Any thoughts? Engine/powertrain feels totally normal at all times otherwise.
I've noticed sporadically I have a strange "crunch" sound that happens somewhere right after startup, and I noticed today it happened after it had been idling for 30-45 seconds or so. It sounds quite ugly. Doesn't happen often, maybe once every 10-15 startups.
Any thoughts? Engine/powertrain feels totally normal at all times otherwise.
04-20-18, 05:00 PM
#2
Pole Position
Hey all-
I've noticed sporadically I have a strange "crunch" sound that happens somewhere right after startup, and I noticed today it happened after it had been idling for 30-45 seconds or so. It sounds quite ugly. Doesn't happen often, maybe once every 10-15 startups.
Any thoughts? Engine/powertrain feels totally normal at all times otherwise.
I've noticed sporadically I have a strange "crunch" sound that happens somewhere right after startup, and I noticed today it happened after it had been idling for 30-45 seconds or so. It sounds quite ugly. Doesn't happen often, maybe once every 10-15 startups.
Any thoughts? Engine/powertrain feels totally normal at all times otherwise.
Does it sound more like a vibration? How long does it last? I had this sound two years ago that was diagnosed as a vibrating or bad exhaust manifold and replaced under warranty. In the beginning, it happened once in a while, then almost every time I started. The problem has returned but doesn't happen often, so the dealer says they won't diagnose to fix something if they can't replicate the problem. So, I am just having to wait until the problem worsens. It has not affected my car's smooth running.
Here's the link to the thread where I have posted videos of the sounds. Your description doesn't match my vibrating sound, but it is worth taking a listen.
https://www.clublexus.com/forums/ls-...1st-start.html
04-22-18, 05:57 AM
#3
Lexus Fanatic
Thread Starter
It’s not a rattle, it’s like two things impact each other that shouldn’t for a second...
04-22-18, 08:25 AM
#5
It could be the A/C compressor "slugging". Refrigerant oil can migrate down to the compressor after sitting a while, and when the HVAC turns the compressor on, it passes this "slug" of oil through it, making a sometimes-startling noise. To see if that's what it is, turn the climate control off before shutting the car off, and see if it makes the noise with the system off on the next start.
04-22-18, 09:27 AM
#6
Hey all-
I've noticed sporadically I have a strange "crunch" sound that happens somewhere right after startup, and I noticed today it happened after it had been idling for 30-45 seconds or so. It sounds quite ugly. Doesn't happen often, maybe once every 10-15 startups.
Any thoughts? Engine/powertrain feels totally normal at all times otherwise.
I've noticed sporadically I have a strange "crunch" sound that happens somewhere right after startup, and I noticed today it happened after it had been idling for 30-45 seconds or so. It sounds quite ugly. Doesn't happen often, maybe once every 10-15 startups.
Any thoughts? Engine/powertrain feels totally normal at all times otherwise.
04-23-18, 01:32 PM
#7
Lexus Fanatic
Thread Starter
It comes from somewhere around the engine for sure, I can sort of feel it. It definitely doesn't feel right, and my 2015 never made any sort of noise like that.
It was at the dealer today for the 5k service, of course they "could not duplicate it"
It was at the dealer today for the 5k service, of course they "could not duplicate it"
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04-24-18, 06:41 AM
#8
Advanced
I guess you are going to have to do the process of eliminating certain areas...... and this will take some time and patience.
Week 1 Start the car with the AC off for a few days.
Week 2 After starting the car IMMEDIATELY put it in neutral.
Week 3 After starting the car keep your foot on the brake.
Record outdoor temps, number of occupants in the car, record how long the car was sitting before starting..... Basically keeping a log until you can pin point the problem. This can be ANYTHING so be patient.
Week 1 Start the car with the AC off for a few days.
Week 2 After starting the car IMMEDIATELY put it in neutral.
Week 3 After starting the car keep your foot on the brake.
Record outdoor temps, number of occupants in the car, record how long the car was sitting before starting..... Basically keeping a log until you can pin point the problem. This can be ANYTHING so be patient.
04-24-18, 11:46 AM
#9
Former Sponsor
It could be the A/C compressor "slugging". Refrigerant oil can migrate down to the compressor after sitting a while, and when the HVAC turns the compressor on, it passes this "slug" of oil through it, making a sometimes-startling noise. To see if that's what it is, turn the climate control off before shutting the car off, and see if it makes the noise with the system off on the next start.
04-24-18, 11:59 AM
#10
Lexus Fanatic
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