Knocking Sound from Engine Bay at idle after warm-up, 2025 GX 550 Overtrail

[NCGX]

Hi All, we just bought a 2025 GX 550 Overtrail a few weeks ago and have noticed a knocking sound at idle coming from the engine bay after the engine has reached normal operating temp (I.e. after 10 min of driving or so). The sound is very noticeable from the cabin, especially when stopped at a stop light. The vehicle only has 800 miles. Has anyone experienced this sound? Please listen to the attached file.

Thank you!

 

[DJ’s Sled]

I’m not sure. I think it may sound just like my ‘24 once warmed up..especially stopped, with the hood open?

 

[Michael-Dallas]

Sounds like lifter tick.

 

[incognito.gx]

Hi All, we just bought a 2025 GX 550 Overtrail a few weeks ago and have noticed a knocking sound at idle coming from the engine bay after the engine has reached normal operating temp (I.e. after 10 min of driving or so). The sound is very noticeable from the cabin, especially when stopped at a stop light. The vehicle only has 800 miles. Has anyone experienced this sound? Please listen to the attached file.

Thank you!
View attachment 17848

Got any videos of the sound from the cabin?

 

[NCGX]

Got any videos of the sound from the cabin?

Not yet, wife is driving the car, but I’ll make sure to record and upload it when I get a chance. BTW, I did take it to the Lexus dealer in San Diego, and they claim the noise is normal. Don’t know if I believe it, but will definitely keep an eye (or better yet an ear) on it. Other than that and the insanely loud break squeal and the cracked taillight, the GX is amazing.

 

[Michael-Dallas]

- if it bothers you, then perhaps try a 0w-30 or 5w-30 oil.

Brake squeal- easy fix for DIY, get some brake grease from auto parts store and apply between back of brake pad and backing plate. The grease will dampen brake vibration, which should stop the squeal. Brake pads squeal because they aren’t in operating temperature range yet.

 

[Larry]

Sounds like basic fuel injector noise.

 

[G gar]

Hi All, we just bought a 2025 GX 550 Overtrail a few weeks ago and have noticed a knocking sound at idle coming from the engine bay after the engine has reached normal operating temp (I.e. after 10 min of driving or so). The sound is very noticeable from the cabin, especially when stopped at a stop light. The vehicle only has 800 miles. Has anyone experienced this sound? Please listen to the attached file.

Thank you!
View attachment 17848

Sounds horrible, I have a 25 OT with 7500 miles and have never heard anything like it.

 

[BryanM68]

My 25 OT does not sound like that at all.

 

[NCGX]

Thank you all for your replies. I may take it to a different dealership for a 2nd opinion. I agree, the “diesel sound” does not sound right, especially for a new gx550, with only 800ish miles. Have not been impressed with Lexus quality thus far (loud brake squeal, cracked tail light from the factory, and loud sounding dieseling at idle when warm). They may have lost their quality touch. Buyer beware…

 

[jfalabrino]

If I were you I would ask for a new GX because of the pro with the 3.4 V35A engine in the GX. The issue is well documented and a known hazard. The 2 rear bearing journals and rod bearing are failing in some Gx's. Most are failing between 7,000 and 35,000 miles. Most of the failures are in the Tundra trucks.

 

[munkeeboi]

Ha. I wish it was that easy to exchange a GX.

25’s are so far unaffected. I have a 24 with no issues and based on the video, that sounds like the fuel injectors accentuated by the phone camera and the higher pitch of the noise.

Might be worth it to take out to an independent Toyota/Lexus mechanic to see what they say.

 

[NCGX]

Hello all, no new real update here other than that the noise is still present at idle when warmed-up… mileage is now at 1600 miles or so. I’ve had two people from the dealership say that it’s normal noise from the fuel injectors, but still find that a little hard to believe. I tried to record how it sounds from the cabin, but failed miserably. I’ll try again and upload a quick sound bite when I get a chance to drive it again (since it’s the wife’s car). More to come later…

 

[Spearone]

Have Tundra owners reported having that same knocking sound at idle?

 

[jfalabrino]

My 24 has 20,000 miles and never sounded like that. If I were you I'd take it back to the dealer and park it in there lot and tell them that they have 2 weeks to either fix the knocking or get you a new one. If they refuse I would contact Lexus customer support and report the problem. Tell them they either fix it or replace it. If they don't then it's time to hire an attorney. It's not supposed to make that noise. With all the problems Toyota has had with that engine you have a good case.
Sometimes you have to get a little aggressive.

 

[Spearone]

My 24 has 20,000 miles and never sounded like that. If I were you I'd take it back to the dealer and park it in there lot and tell them that they have 2 weeks to either fix the knocking or get you a new one. If they refuse I would contact Lexus customer support and report the problem. Tell them they either fix it or replace it. If they don't then it's time to hire an attorney. It's not supposed to make that noise. With all the problems Toyota has had with that engine you have a good case.
Sometimes you have to get a little aggressive.

I agree, that sound should not be coming out of a gasoline engine. It sounds like a small Perkins marine diesel.

 

[G gar]

Hi All, we just bought a 2025 GX 550 Overtrail a few weeks ago and have noticed a knocking sound at idle coming from the engine bay after the engine has reached normal operating temp (I.e. after 10 min of driving or so). The sound is very noticeable from the cabin, especially when stopped at a stop light. The vehicle only has 800 miles. Has anyone experienced this sound? Please listen to the attached file.

Thank you!
View attachment 17848

I have a 25 OT with 8700 miles and have never heard this noise. Not normal, take it to the dealer.

 

[Nickal]

Hi All, we just bought a 2025 GX 550 Overtrail a few weeks ago and have noticed a knocking sound at idle coming from the engine bay after the engine has reached normal operating temp (I.e. after 10 min of driving or so). The sound is very noticeable from the cabin, especially when stopped at a stop light. The vehicle only has 800 miles. Has anyone experienced this sound? Please listen to the attached file.

Thank you!
View attachment 17848

Same noise mine makes but mine also has significant vibration. took to Pines Lexus twice and was told this is normal for this engine in particular and there is no fix.

 

[Spearone]

Same noise mine makes but mine also has significant vibration. took to Pines Lexus twice and was told this is normal for this engine in particular and there is no fix.

Yikes!

 

[G gar]

Yikes!

Mine is very quiet, you can’t even hear the engine running at a stop light.