fastnoypi

You're definitely not facing rings and seals unless you have catastrophic misfire. A simple compression test and/or leakdown test will show. Its highly likely the baffles in your 1st gen rear valve cover are all clogged up...in that case, your pcv is just suctioning your oil right back into your intake.

Dukenukemx

So could this be fixed by removing the rear valve cover and cleaning the baffles?

fastnoypi

Technically yes, but it might be more effort than its worth to refurbish a v1 or v2 valve cover unless you have another daily driver in the meantime than to bolt up a better designed v3 rear valve cover. It takes a long soak in some chemical solution to breakdown the sludge that is in the baffles unless you have access to a hot tank parts washer. Afterall, it is alot of tedious work to remove the intake manifold to get to the rear valve cover.

owenstrawn

Update: Replacing the PCV valve (twice) and using Seafoam helped for a while (one trip used no oil at all), but by now it is worse than ever. Our most recent 600 mile trip used 9 quarts of oil!

We have another 3000 mile trip planned for next month and we were planning to rent a car, but instead I have decided to take a chance on the G3 valve cover swap. I found a 2006 Sienna valve cover on eBay for $60, but it's got a fair amount of varnish and carbon. With such a huge labor overhead I think I am going to order a new one instead. Can anybody recommend a specific online Lexus parts dealer or is that against the forum rules?

Thanks!
Owen

salimshah

Forum rules are against self advertising unless you are a sponsor.

There are others too ... like profanity/copy_rigths/threatening_language etc etc.

Salim

trhs75

I just bought a valve cover and other parts online from McGeorge Toyota in Richmond, Virginia. I am hoping to solve this same problem. Many of the vendors mentioned on here that I used to use are no longer selling parts online. Everything went great with my purchase, and I plan to use them again. Prices were among the lowest if not the lowest that I'd seen lately.

owenstrawn

Maybe a dumb question, but considering how hard it is to get to the rear plugs, how hard is it to do a leakdown test?

fastnoypi

its twice as hard or six times as hard..depending on how you look at it and/or if you have your intake manifold off. You have to remove each plug individually and thread the adapter into each sparkplug hole...run your test, then remove and replace the adapter with your sparkplug and move to the next plug. Obviously it would be easier when you plan to do a spark plug job and remove the intake manifold.

salimshah

Can you expand on why you want a leak down test? I am not getting the connection to the current thread.

Leak down test is more elaborate than the compression test. You can get lot of information (which may be related to this thread) by doing compression test. Granted due to access problem the compression test is not going to be easy on the bank next to the firewall.

Salim

owenstrawn

fastnoypi

if you are running rough at idle and feel your plugs have been gapped correctly and elimintated the possibility of ignition issues..it would be the time i'd consider a compression/leakdown test. If it is running smooth at idle, i wouldn't waste my time. My comment was to TRHS75 because he had an assumption that he had bad rings.

Lexmus

Apologies trhs75 for not noticing earlier that you asked this question. The oil catch can goes between the PCV valve and the intake. There is short hose that runs between the two that you remove. I had foot long or more hoses that connected to the PCV and the intake and that also attached to the catch can that was in the middle of the two hoses. I sat the can to the left, with a zip tie holding it to the dogbone mount so it didn't bounce around too much. I would cut the zip tie when checking/emptying the can and then reattach with a new one.

trhs75

Thank you, Lexmus -- I hope to give that a try. Right now, I have the car tucked in a corner of the garage ready to install the new valve cover. While things are apart, I hope to do a compression test. I picked up a cheap tester at Harbor Freight today. Videos I've seen recommend doing this with the car warmed up, but I'm not about to try accessing the rear spark plugs on a hot engine. If I test all six cylinders with a cold engine, shouldn't the readings all be close to the same if everything is okay, and a bad cylinder will still stand out?

salimshah

Pardon me from being philosophical ... I learnt this lesson a while back ,,,, if you dont have a plan based on test results then dont do the test.

In this case, if the compression test comes out fine ... good to know, but what if one or more cylinders show bad compression? Are you going to have a leak down test and rebuild the head or do a full engine overhaul .. re-bore, new piston + rings?

Fast gave you good advice ... if the engine idle is fine and the engine runs smooth, then skip the compression tests altogether.

To confirm the oil consumption through the intake ... put a catch-can

If the oil is through the rings, based on milage either keep adding the lost oil or consider doing an overhaul.

Salim

Lexmus

trhs75,

I did a dry compression test a couple of years ago on my RX without taking off the intake manifold when I changed the spark plugs. My values were as follows for cylinders 1-6 in order: 194, 202. 205, 200, 205, 205. It probably took about 6-7 compression strokes while cranking for the pressure to stabilize at the max value.