CowBoE

Just did the valve cover gasket replacement on 3MZ-FE engine on 2004 Highlander,
where same engine is used on 2004-2006 Lexus RX330, and 2005-2009 RX400H.

While I had everything open, I did more work.

This was not a quick DIY and had many challenges, but I'm so glad to be done with this.

1. Replaced valve cover gaskets
2. Replaced spark plug tube seals
3. Replaced spark plugs
4. Replaced PCV
5. Replaced fuel injector O-rings
6. Replaced broken connectors
7. Replaced broken EVAP hose
8. Cleaned intake valves
9. Clean MAF & TB

You Tube

MattRX

Nice DIY, thanks for posting! Reminds me of the fun time doing it on my 2002 Highlander, and the even worse time on my 2008 RX!

CowBoE

My friend, who's also a hobby weekend mechanic like me, asked me to the same work on his 2006 Sienna with the same engine because it looks too hard for him.
I said no thanks, and that this is a good one time challenge/experience for all hobby mechanics to go through. LOL

Margate330

Hi cowboe, sounds like you got to dig in deep.

It can be intimidating for DIY or for the first time pulling the manifold but like you say, after getting that experience it's a breeze.
I don't know about you but removing and replacing the rear valve cover is tight back in there for me, almost no room.

CowBoE

When I watched other videos, I was thinking how hard that can be...
and while doing the work, I was like, may be I should've just paid to get it done. LOL

Looking back, really the only hard challenge is removing and re-installing the rear valve cover,
rest are just removing bunch of bolts, hoses, and connectors and keeping removed parts/bolts well organized.