dalbert02

Hi! First post. I have a 2004 RX-330 that had a P0327 code. This is Anti-Knock sensor error. I bought new sensors and wiring harness per a thread here. When I took off the intake manifold, I found orange coolant 'crystals' in the space between both cylinder heads and completely covering the knock sensors. Now, I can not be certain where the leak is coming from but I am going to change the intake manifold gaskets and the bypass hose that runs in this space.

There is a cover in the middle of the engine under the intake manifold. Below is a pic from another thread with the cover removed. What is the name of this cover? I'd like to replace this covers gasket as well but I don't know the name of it.

I hope I hope I do not also have a cylinder head gasket leak!

Thanks,
-dave

Ignore the part circled in black, that is where this other person had a leak.
https://www.clublexus.com/forums/att...k-img_0497.jpg

NotADood

Believe it or not, that is part of your upper thermostat housing. A leak there is very common, as Lexus/Toyota only used an RTV compound to seal it instead of a gasket. It would be a good idea to change your thermostat and gasket while you are removing it.

dalbert02

Thank you sir. I took the housing off and the black RTV gasket was falling apart in my hands. It was disintegrating everywhere and very brittle. I bought a new thermostat and gaskets like you mentioned and new spark plugs since I am at 120,000 and have access to them.

HtownBlue

You might consider replacing the rear coils and plugs while you've got it all apart. Also I would replace the valve cover gaskets while you can get at them easily. Just a preventative measure which may save you from having to tear the top end off again in the future.

dalbert02

Thanks. Good tip, but too late. I changed the plugs but not the coils, I'd assume they are pretty pricey anyways and between knock sensor, wire harness, gaskets, fluids, and supplies I am at $500. Oddly, it looks like the plugs were partially changed once already, the fronts were NGK and the rears were Denso. I have her put back together but tomorrow I add the fluid and see if my work was good. No extra parts or vacuum hoses that didn't find a home so I am pretty positive. The 'hidden' bolts up against the fire wall were a @#$%. There are two at the throttle body and one behind the black plastic intake.

HtownBlue

Yeah those bolts in the back are horrendous. I had to use a 12mm ratcheting wrench click by click to get them undone.

amleigh

I just got a call from the Lexus Dealer for my 2004 RX330 stating that it will cost $1500 to replace this gasket. They say it is a lot of work and they have to remove the intake manifold before they can get to this cover. The $1,500 seems way steep. Should it cost that much?

Rainbird

Seems high, get a second estimate from Toyota or an independent shop.

amleigh

Thanks. Is there a way to look up how many hours the job should take?