dragular

Has anyone ever changed their valve cover gaskets??

i have a 1999 RX300 with 100,000KM on the ODO and i am experiencing a small oil leak by rear valve cover. Had this leak for a couple months but never saw oil on the ground as it leaks extremely slow and it usually burns off when it hits the exhaust pipe.
Also my oil level does not vary between oil changes.

Now i do suspect that the leak is affecting the spark plugs and causing a slightly rough idle (500rpm when on drive & 750rpm when in park or neutral but fluctuates). I already cleaned the MAF and IACV and the problem still remains. Once i'm not in traffic i dont even know the problem is there but when in traffic it is very annoying because i notice it.

So do you guys think that my valve cover leak could be affecting my idle??

and also is there a DIY for changing the valve cover gaskets??

code58

Your valve cover gasket wouldn't but I suppose it is possible that if the seal around the spark plug was leaking it might be possible. The seals for the plug holes come in the VCG set. You might try pulling the plug on the COP's 1 by 1 and seeing if 1 of the cylinders seems to be the culprit. Then remove the COP and take a mirror and take a look into that hole and see if you have oil accumulating around the plug. It's going to be tough on the rear 1's though, you can't even see back there with the intake on.

dragular

That the worst part, the leak is on the rear valve cover. We took the vehicle up on a ramp and saw the leak stemming from there. Looking at the engine from above, you cant tell it even has a leak.

I already ordered the valve cover gaskets and a new PCV valve as well.
This is the gasket set that i bought:
http://www.amazon.com/Beck-Arnley-03...tive&carId=007

I hope to get this sorted out by next week. The labor is going cost me!!

code58

I hope you get the right gasket set. When I got them for my DIL's 99RX the ones they gave me were the wrong ones. When I took them back they showed me on the screen that they were listed as the correct ones but when they found a second choice that was not listed as the one for it, they were correct. Good Luck!

thomas1

by the way look under knock sensor replacement....I believe you are going to have to take the air plenum off to get the valve cover gasket...just remember the bolt (14mm) behind the plenum on the pCV valve side is a nighmare. A quarter inch socket set with 14mm works, but it is really tight. There are two more bolts on the back side as well, one for a ground strap, and one for another support bracket (left side of car) Once those bolts are undone, their are two bolts and two nuts that hold the Plenum on the intake manifold. Note there is just not much room between the firewall and the air plenum and a gear wrench will not get the 14mm bolt because it is recessed in a u shaped support bracket. After I took mine off I modified that bracket (a little grinding) and added a washer under the bolt so that the head of the bolt could be accessed by a gear wrench. Went on much smoother than the 1 and 1/2 hours to remove it...Here is the Knock sensor replacement, you do not have to go beyond the air plenum.....
http://us.lexusownersclub.com/forums...=knock+sensors

dragular

thanks for the heads up

thomas1

Also note there is a rubber grommet around the PCV valve...if the valve is clogged the oil could be pushing past the grommet....

Bobster999

Im surprised you were able to get a socket on the bolt. I cant even get a socket on there without even using the rachet. lol... im very frustrated with this.

Bobster999

I looked around here only found sketchy info. I cant seem to get to the 14mm bolt holding the intake manifold on. Everything else is removed. I tried to snake the v/c out where i removed the throttle body with no luck. I saw one guy said he removed the bolt using a 14mm 1/4" socket. I cant even get a socket on mine much less a rachet. How did you remove yours?

Bobster999

Hi there! Im trying to replace my rear valve cover but i cant get a wrench or anything on the bolt holding the manifold to the rear support. I have removed the throttle body but cant seem to snake it out that way either. How did you do yours?

salimshah

Look at knock sensor DIY for hints about hidden bolts to remove the top end.

Salim

JabobJeff

This video should show you how to do it.