omarkhan78

Hi Guys,
I have been having a rattling problem from my rear back seat from the day one of my LEXUS RX 350 2012 purchase. I have tried may thing but the noise still exits. its appears only when going over pot holes at speed of 30 to 40 km.The dealer has mentioned it as a common phenomiman and refused to look into the noise problem.
After a few days of purchase, to check the rust proofing was done proper, I looked underneath the car at the dealer and found a few lines of greasy substance on rear sub frame (Underneath the car trunk)of the car which is the side from where the noise comes. It was told that its was rust proofing material and will take time to dry.

yesterday(after a 1 year) I looked underneath the car again the lines are still greasy. I have uploaded a few images and will upload a video soon. What is it? It does not appear on any other part of the frame? Was it welded?

Thanks



.

Clutchless

Looks like a thick layer of still pliable rust proofing that is out of the way of most road debris so still looks fresh. I would not worry about it.

I also doubt it has anything to do with the mystery noise. Most often that noise is related to the rear hatch roll over cover, or the rear seats not being latched in correctly. Do a search, this has been covered before. I usually remove the roll over cover as it is noisy.
Less likely is something inside one of the pillars bouncing around. You should ride in the back while someone else drives so you can pinpoint the location.

omarkhan78

Thank you for your reply. The thing i am concerned about those thick line of grease only on rear frame on the left side. Its doesn't look perfect, it goes random as if it is covering something.
There is no grease on any other part of the car.

RickC5

Have you actually touched these "greasy" spots? I'm thinking that what you took photos of is not grease, but a chemical interaction between the undercoating that was sprayed on with some factory sealant, which has caused the undercoat to not completely dry, leaving it glossier. Lots of factory sealants (glues) remain soft & sometimes tacky for years. The fact that the glossy areas are in such nice, straight lines--right where the factory sealant is-- is what leads me to think this. Check it out, those areas may be soft & tacky--not greasy.

omarkhan78

I had touched it. it with my fingers and its was sticky ,i had to wash my hand with soap to clean it, How do i confirm if its factory sealed ? some place it straight lines and its some places it goes random as you can see in one of the pics.

RickC5

Now that you've confirmed it isn't grease, I wouldn't worry about it any more. Once some dirt gets on those glossy areas, they won't be tacky/sticky any more. Or, eventually the undercoat will dry.

lexusrus

Could it be the tire dressing, like Armor All?

Clutchless

No. That stuff does not last long enough and would not likely be sprayed such that it appeared like those things in the photos. Again, this is nothing to be concerned about.