Popobich

Hello,

I bought a used 2013 RX 350 with 34,400 miles. I live overseas but the car was manufactured in USA. After about 5 months of ownership I noticed that one of the injector vibration insulator (the seal that goes between the injector and the intake manifold) has some oil residue as shown in this picture:


That was the one on the passenger side and on the back. I wiped it clean and monitored it for about 2 weeks and noticed there was what it looks like oil residue.



Thought it was the insulators that needed replacement so I ordered new replacements and replaced the upper and lower seals (part no.
23291-23010 and 90301-07033. After replacement I monitored it for about 2 weeks and seemed like there was nothing coming out.



After about 2 months I decided to take a look and found out there was some residue.


I think it started leaking way long before the 34k miles. These are the old insulators and you can see the pressure marks from the injectors when they were installed:



I know there is always some residue similar to oil called blowby coming from the vents of the valve covers. Thought it could be the pcv but since the intake manifold is separate from the valve covers maybe it's not the pcv. The residue smells more like burnt oil which makes me think it is from the blowby. I found no fuel leaks and apparently no other oil leaks as it only gets wet on the lower part of the injector. When took out the injectors, I noticed some carbon deposits on the tip. I think the intake valve has some deposits preventing the valve to fully seat and when combustion occurs some pressure blows back to the injector making it wet in what seems like oil so that it also gets wet on the outside.

Apparently it also happens on the next injector since it was also wet. Here I put the new vibration isolators in the manifold.



The car runs fine, no engine vibrations other than normal (very minimal). I also replaced the plenum gaskets as well as the throttle body gasket. I also cleaned the throttle body and seems to run better (more responsive). I couldnt check on the valves since I don't have a borescope. I will check the pcv valve with a vaccum pump this weekend.

Yesterday, I added 150ml of liqui moly valve cleaner to a full gas tank and seems to run smoother and more responsive than before. I will try to clean the valves with this cleaner to see if there is any improvement on the oil residue.

In the meantime, have any of you experienced this or have an idea of what it could be? Any help would be greatly appreciated. I tried searching on this forums and on others but couldnt find any other case.

Sorry if at some point, I didn't make myself clear. English is not my native language.

Thank you in advance.

Clutchless

Welcome to CL. Since the 2nd gen Highlander is a mechanical twin and the folks at Toyota Nation do more of their own repair work, I think you should search over there and maybe you will get more responses, or find something in their sticky thread for repairs
https://www.toyotanation.com/forum/1...ion-2008-2013/

You may want to have a shop do a fuel induction service to clean the intake system and valves if the gas tank additive does not help much.

RX in NC

^^ Good advice above. This is the first I have read of this particular issue. Good luck with your repair efforts and keep us posted on your progress.