UDel

I have a oil leak on my GS430 that from what I can see coming from the Valve covers/gasket. Not a really serious leak, just a few drops here and there mostly during very cold weather. I have been using Mobil 1 5W 30 Full Synthetic since I owned the car. I have heard after 75K miles the full synthetic at that weight will likely start leaking out of the gaskets and I might want to try a heavier weight.

Has anyone tried a heavier weight/thicker oil to help with leaks, what did you try?

Has anyone tried a engine treatment for leaks like Lucas Engine oil stop leak(I know car manufactures don't recommend it, they don't recommend any DIY and only recommend taking it to a mechanic)? What were the results?

I think I would rather do the valve gasket job myself but don't have time right now, where are the bolts for tightening it, I see several bolts, not exactly sure which ones I need to tighten as I heard tightening bolts a little can stop leaks, thank you.

FrankT

How about just replacing the two valve cover gaskets. Find an independent shop and use Toyota parts. Should be less than 2 hours labor.

UDel

I would rather do it myself and save the money, the prices are too high just to change out 2 simple gaskets, I don't know of any good independent shops around me, I only use Toyota/Lexus service departments for things I can't tackle which charge a lot for the service. I am in the market and will be paying a chunk in taxes coming up very soon too. In the meantime I would like to try something that would lessen or stop it like heavier weight oil/treatment until I get around to it.

3UZFTE

I would bet you'd still be leaking oil no matter what weight you went to, by changing the viscosity if your changing the rate at which an oil flows through a fixed oraface. Essentially you'd be just slowing the leaking down, but you'd probably have to go to such a thick oil to really make a difference I probably wouldn't recommend it because by the time you go back, it will probably start building tolerance for the thinker oil. Your probably not going to notice a difference from 5w-30 sun to 5w-30 conventional, but let's say you put 10w-40, you'd probably notice a difference, but just switching to conventional is going to solve your issue, it's just going to save you money from putting synthetic in it.

takashi

I had my valve cover gaskets changed a few miles back on my GS400 when I had my plugs changed.

Although it sounds like a straight forward job, you have to work around limited spacing,
and make sure the gasket does not get kinked or pinched during the install.

It happened to me, and it will leak a lot of oil, and had to get it done again.

It's worth changing it though, the grimy engine block is not pretty

Jvgs300

Just got oil change on my gs 300 my car is leaking too Lexus mechanic said to use Lucas oil stop leak. I'm going to use ATP at-205 reseal waiting for it to come in the mail.