I just bought a '99 GS300 with 118,000 miles on it. Interior and exterior are in excellent condition and everything runs/sounds great. However (and I knew this when I bought the car), there's a slow oil leak up high on the engine. Makes a mess. I'm fairly certain its the valve cover gaskets after all the reading I've done on CL, and that everything above the valve covers is dry and everything below them has oil on it.

Anyhow, this weekend I'm changing the timing belt because the prior owner couldn't tell me whether it had ever been changed and there's no indication on the engine that it was. I pulled the top covers and noticed quite a bit of oil under the cover. There's none on the belt, but everything is wet in there. I snapped the attached pictures that kind of show what I'm talking about.

Heres my question: Could all the oil be caused by my leaking valve covers, or is it something more serious, like cam seals? From what I've read, I definitely want to get all that oil cleaned up before I put a new timing belt on, and want to know how far into the engine I need to tear this weekend. Thanks for the help.

 

might be cam seals or vvti cam gear starting to leak

 

Yea looks like the cam seals have failed. Replace those with the valve cover gaskets...

 

ALWAYS replace cam seals and crank seal when doing your timing belt. Also replace your water pump and valve cover gaskets.

Once all that is properly taken care of, your oil leak will be no more. And you won't have to worry about another one for 90k more miles.

It wouldn't be a bad idea to replace the O ring on your VVT-i cam gear, too. Jeff Tsai has a how-to video on youtube. Channel name is "teamproject".

 

Great information I also needed thanks guys

 

Works for me-Thanks for the help guys. Any idea why they're replaced so often? I've had two ford V8s with over 150,000 miles that didn't leak a drop from the crank or cam seals (although they had their fair share of other issues/leaks). I like the overall setup of this engine and am trying to learn as much as I can about it.

 

They're replaced as often as the timing belt is replaced because you have to remove the timing belt to replace them. It's a "while you're in there" type of job. Most non-dealer shops and mechanics will just do it by default as a part of the major service.

That said, mine were NOT replaced by Lexus at 89k miles when I had the T-belt done. Here's a little secret...Lexus won't replace these unless you specifically ask them to because they know you'll be back in between 120k and 150k miles to have the oil leak fixed. $$$

When I recently went NA-T, Jeff had the head off and inspected the seals for me. Both of my cam seals were cracked in half at 120k miles. They would have been leaking any day now.

 

Definitely an Oring within the vvti cam specifically. Had the same problem couple months back. Hit up this guy, it's decent and doesn't hurt the wallet. Shipping takes a while though.. from experience http://powerdynamix.com/

 

It's the same guy.

 

Wondering if this is specific to the GS300, my GS400 has 180K no seals were changed just timing belt, water pump, drive belt at 100K. Need to top off half a quart of Mobile one synthetic at 5K then change the oil entirely at 8K with 5 fresh quarts, I don't think that is too much oil consumption.

 

On the 400 I wouldn't want to do it each timing belt replacement. The job is way too tedious to do it on every timing belt service. I don't know about the 300's, can't speak on those but I've replaced the cam seals on my 400 and it took me the entire weekend since the V8 requires removal of the entire camshaft just to remove/replace the seals.

rylexus, do you know for sure if the cam seals were ever done or not? If not, then you maybe overdue. Since you are using synthetic oil, I would've recommended replacing the crank and cam seals. They do leak over time on these engines.

 

Good tutorial. Would that information apply to the 1999 LS400 as well?

 

Hi i have same leak on there. Will this cause damage oil control valve ?