Boypony

Hey Guys-
In my previous thread I showed pics of the Gen 2 & 3 valve covers and how to ID them from the outside.
In this thread I will show you what I believe causes the problem of "oil-sucking" through PCV system.
There is a factory applied black coating inside the baffle plate in the cover. You can see it even in areas
that were under the riveted sealed areas. It seems to me that this coating swells and breaks down, causing
poor airflow and liquid oil to accumulate and get sucked through PCV valve. My 168K 2002 hasn't lost a drop
of oil in 500 miles of highway 75mph+ driving. Before changing to the Gen 3 cover I would have used over 2 QUARTS
of oil. Remember- just because you have the "screw-in PCV valve" that doesn't mean you have the "new" cover!!!
See my previous thread to determine if you have Gen 2 or Gen 3. Gen 1 and 2 can be oil suckers.
BTW there was no sludge build up and motor had approx 180 psi in all cylinders with compression test.

Here are some pics of my old Gen 2 cover after I removed the baffle plate for a look see.

Boypony

Huh...guess no one thinks this info is worth anything.......I'll think twice before wasting my time trying to help next time.

JAB

Please don't think that! These types of posts are invaluable.

salimshah

Boypony:

There is information, discussion and conversation/debates.

Your thread here is informative and is/will_be useful for other.

Please do no determine the value of a post based on how many replies it gets.

Salim

Drcoffee

+1

I used your info to source a valve cover on ebay. Since so many models use this motor, I simply searched Toyota valve cover and screened the pictures looking for the 4 notches. Ended up finding one from a "Sienna 2005". all to often the sellers mis-label the vehicle part. I should have posted a big thanks sooner.

Boypony

Thx DrCoffee- you're restoring my faith in CL

Drcoffee

There are a bunch of voyeurs here and only a handful of participating members. Don't be discouraged. You will quickly see the same 5 or 6 members helping the hapless others. LOL

Some say I don't play well with others. I have no idea what they mean.

fastnoypi

I had the impression your pcv hose restrictor attempt worked due to no additional updates in the other valve cover thread and your last positive results.

salimshah

I have been with the RX forum from its inspection. I never thought that Lexus brand owners would be DIYers back then. I have been proven wrong. Just look at the list of DIY and also note how many ES members take cues from RX forum.

The member's mechanical inclination in Lexus line as whole and RX in particular will never match the tuner/tinkerer level of say Honda Civic or Subaru.

Also note the culture as indicated by the postings is something to be proud of.

Salim

Drcoffee

She is adding oil every 2-3 weeks. So the pcv line restrictor on the gen2 valve cover isnt working. When she comes home for Christmas, I will have replace it again. This tme with the gen3.

Drcoffee

I received the used gen 3 valve cover last week. Drilled out the rivet heads and cleaned it completely. There appears to be a secondary baffle under the plate. I dont think the gen 2 has this. The secondary baffle seems to be the trick as it allows the vapors to cool in the tower portion of the cover before exiting the pcv. I removed the cruddy coated metal gasket and used oil resistant black silicone gasket maker where the plate makes contact. Then used modified screws to reattach it. A dab of more silicone to the screw heads will keep them from backing out over time. And finally painted it a tacky copper color for fun.





The real changes though took place underneath the cover. The old version has one baffle plate with a quick route frrom the baffle to the pcv, the new version has a secondary baffle plate under the larger baffle. What it does is direct the vapors from the cam sprocket (front) end under the larger baffle back to the transmission end, where it then passes under the secondary baffle to then travel forward again in the tower before exiting the pcv. Essentially making the vapors travel 16" before exiting (compared to 2"). There is a 1/2" dia tube you can partly see in the picture that is about 3/4" long that has a steel perforated plate at the exit, which strains the vapors of oil. Brilliant design IMO.



As for the coating, lexus/toyota are all about quiet engines. my best guess is that the coating is an attempt to quiet the oil slung off the camshaft, producing a tinny sound. Something like spraying rubber coating in the fender wheel wells to lower road noise. Sadly, it swelled up and blocked the passages causing poor oil drainage.

thaeleelyr

What was the reasoning behind drilling out the rivets and replacing with screws? Cleaning?

Drcoffee

Yep. To clean out all the loose coating and coked oil on the underside. Its as clean as a whistle now. Mine looked just like the pictures above in post 1




.

cwsteini

Boypony,

Hey man I don't frequent the forums too often but I want to personally thank you for this post and let you know that this sort of information is EXTREMELY VALUABLE and to keep it coming man.

Also, you may want to consider replacing your catalytic converters if you were burning a ton of oil for a very long time. Of course everyones car is going to be very different but for me replacing the catalytic converters was a god send. I had been burning oil for so long, before addressing the rear valve cover and fixing the issue, they were totally destroyed and clogged which was keeping my engine from freely exhausting and super heating my O2 and A/F sensors so they would fail about every 6 months!!

If anyone is experiencing weird exhaust sounds as though the exhaust system isn't freely able to breathe and you're getting high pressure blow outs and your sensors are failing often like I described then your CATs are more than likely in really bad shape. ALSO FYI, I had pressure tests done twice at two shops to see if the CATs were clogged and both times they claimed they were fine.., but I ultimately went with my instincts after observing my car and listing to it and eventually just went ahead and purchased new CATs and had a shop install them and when I opened the old ones they were in fact COMPLETELY DESTROYED and CLOGGED!! So trust your instincts and don't take what a shop is telling you as gospel truth.

Again, thanks Boypony for sharing these photos and valuable information.

Macmasdad

In anticipation of Drcoffee soon posting his Copper Gen 3 cover successfully solved his daughter's oil consumption issues and thereby creating a bidding war on the remaining Gen3 covers left on ebay....I just pulled the trigger on one of those ebay Gen 3 covers.

I already planned on soon tearing apart the top of the engine to:
-change the knock sensors (the infamous hack has temporarily shut off the CEL)
-change the valve cover gaskets(minor leakage on both right/left) and spark plug tube seals
-change rear spark plugs (prior owner said they were done right before I bought the vehicle. But since I am right there, I will make sure they are done.)
Therefore, I have been reading all the various threads to decide if just thoroughly cleaning the Gen 1 cover would be good enough. Based upon this thread(thanks Boypony, Drcoffee, cwsteini), I decided the evidence on the Gen 1 and 2 designs vs, the Gen 3 design is clear to spend a little more and make the switch to the Gen 3 cover. While my daughter's 2000Rx is currently used just for local trips back/forth to high school, soon enough it will need to be depended upon for college, work, etc.

Drcoffee, while I doubt I will be recreating your stylin copper cover, I would like to know where you purchased the " blue" spark tube seals from and what is the material? I assume they are an upgrade(FKM?) from the normal rubber, and I assume your valve cover gaskets are upgraded in the same material as well?? Thanks for posting those detailed Gen 3 photos.

cwsteini, I will be rereading and considering your other post that lists out all of the changes you did while the engine was torn apart. I hope that the changes will be enough to prevent future CAT issues you had experienced.

Boypony, thanks again for starting this thread and posting those photos.