Dear Scotty,
i need some help but it might be a long message .
I have an 07 Lexus RX 350 with 188 000 kms. Recently I have done an oil change at an official Toyota dealer and they put me a 0w20 oil instead of recommended 5w30 but that is not the only issue. After getting my car back I noticed that there is a mysterious rattle coming from the belt/pulley area of my engine, which was not there before . It is intermittent and is not related to engine speed, when I rev up my car the noise disappears and the engine sounds good and then once I let of the gas the noise comes back at idle. I have noticed that my serpentine belt tensioner pulley is vibrating like mad and once in a while it stops and the noise immediately dissapears. Then it starts to wobble around and the noise comes back. I took it back to the same service where I did an oil change and pointed them a problem in the pulley and they said that I’m wrong and the pulley is supposed to move and that they can’t locate the source of the noise exactly but it maybe an AC compressor clutch. They told me they did take the belt off and spin manually all my pulleys but have not noticed anything strange. I did listen to the ac compressor pulley as well as alternator using my stethoscope but the source of the noise is clearly not there. Funny part is that my belt and all the pulleys are new and I replaced them 6 months ago. I am a bit dazzled. I have attached a video with my noise.
https://youtube.com/shorts/ULVyqvHpMRM?feature=share
perhaps you can help me how could I approach this problem and PinPoint the exact source of my rattle. I have a long drive coming up this week and I am afraid to drive with this rattle even if it’s on idle.
Thank you a lot in advance!
nighthawk
Another brilliant dealership opinion.
Take the car to an independent mechanic and have him check it. Regarding the oil, I would use the 5W30.
Lexus specifies 5w30 for your year and model, not 0w20. I would take it back to the dealer and demand they re-do the oil with the Lexus specified oil. Too thin a viscosity for your engine can damage it.
OP - good advice from the other members here. I would recommend moving forward you find a good, independent mechanic to take your Lexus to (ideally one familiar with Toyota/Lexus and Japanese vehicles).
the oil the put in could be more viscous than the recommended engine oil. The pulley tensioner being lubricated by the same oil would not work as expected and cause the rattle. Revving the engine or running it on the highway would lubricate the engine better and help push out the tensioner. I suggest changing the engine oil(and filter) first, mostly the difference in oil pressure from the wrong oil type is causing it, IMO.
The serpentine pulley tensioner is not lubricated with engine oil, the timing belt tensioner is. Nighthawk90 is talking about the accessory serpentine belt.
Thank you guys for your input , I guess tommorow I’ll go on a quest to find a decent mechanic and put the right oil in. It is so sad that official dealerships just turn into stealerships to get all the money from you and not do the job decently :(. Hope I did not damage my engine in the process but knowing how tough lexuses and Toyotas are hope it will be fine.
Cheers to all 🙂
So I did an oil Change an out a brand new Liqui Molly 5w-30 oil but the noise did not go away. The mechanic told me it would be a timing chain going out, I did not believe him. So I took my car back to my yard took my stethoscope and wrench removed plastic covers behind serpentine belt covers and found out that my brand new tensioner belt pulley is rattling like mad. Here is the video. I guess maybe I got a bad quality one installed ? Anyways I was very relieved that it is nothing to do with engine or chain. Happy End after all … but you can never trust what some mechanics just tell you
https://youtube.com/shorts/iait5V2v2Wk?feature=share