Lexus oil leak

2001 Lexus GS 300

It's a slow leak. It gets worse at high speeds. It leaks out and burns up on a surface below the manifold. The daily 45 mph 10 mile trips don't seem to affect the oil level. Add a week's worth, a couple ounces need to be replaced.
We have not yet determined the source of the leak.







We think a gasket, maybe. Scary to me. Thoughts?

Below the manifold? It could be the valve cover gasket. I am just guessing without being able to do better investigation. Nothing in the coolant? Not burning it out the tailpipe?

When was the last time you did the spark plugs? You can knock out the gasket and plugs at the same time and inspect things. Not a horrible DIY job.

https://www.clublexus.com/forums/gs-2nd-gen-1998-2005/830223-diy-valve-cover-gasket-and-spark-plug-replacement-gs300-is300.html

The car is newish to us. The oil is pooling on a surface under the manifold. Any smoking appears there.. Not sure precisely where the leak itself is located.

Will look into the spark plugs as well.

Thanks so much for the links!

You may already know this, but just in case... They make fluorescent dye you can add to the oil.  Then you shine a UV flashlight at it and the leak lights up like a beacon.
(Truly a time-saver.  I LOVE that stuff!)

Wait. What?!!! How cool!

According to product description, this dye can be used in the motor oil. Can someone verify that I read that correctly?

Joylynn Hardesty wrote:Wait. What?!!! How cool!

According to product description, this can be used in the motor oil. Can someone verify that I read that correctly?

Just go to your local auto parts store and ask for a bottle of oil dye, They'll know what you're talking about. It's a little bottle, about 1oz or so, dump the whole thing in and drive it around. For a more accurate diag, take the car to the local car wash (or use a pressure washer if you have one) and clean off the area around the leak as good as you can. That will both give you an idea of how bad it is, and make it easier to locate. After driving it for a while, you'll be able to use a blacklight to locate the leak (or, if you cleaned everything off good enough with a pressure washer, youll be able to just see it).

How did things work out?

Ummm... money. Budget is tight. We're waiting for money. And driving sedately. And praying.

Thanks for asking John.

I second the valve cover guess, it's super common on these motors.  When checking oil leaks, I always start at the top most leak, then clean and recheck.  The oil dye is kinda a last resort thing, eventually it just gets all over.  

Be careful if you pressure wash, so you don't get water down the spark plug tubes, and like Timothy said, do your plugs at the same time -  you are most of the way there by doing the valve cover.  

I would also do the plug wires and coil boots as well.  Don't forget to plan on things like the PCV hose and coolant hoses breaking.  In fact, just put a new PCV valve and hose on, I'd bet the old one is rock hard and ready to split.  Get a throttle body gasket in case it tears when you take the air plenum off.  

Final advice - don't use cheap parts, unless you like doing the job again and again.  These days the dealers parts prices are very competitive, and Toyota will sell you parts for that motor - sometimes cheaper than Lexus and usually quicker.

It's past time to take care of this. Sigh. It is still just oîl, so I don't think the coolant is mixing in yet.

So, head gasket, spark plugs and wires, pcv valve, pvc hose, throttle body gasket, coolant hoses.

Aaand it's a head gasket set that I want, not the engine gasket set, right?

Anything else? Has anything been missed?

Okay... head gasket only? Or the whole set?

A head gasket would not be the a source for an oil leak. Valve cover gasket. You may have to replace the plenum to get to the valve cover so maybe a plenum gasket, but probably not the throttle body gasket. Remove the plenum with throttle body still attached.

It appears that there are 2 valve covers side by side on an inline 6 cylinder engine. The exhaust cam cover would be the one on the passenger side. The intake cover probably needs the gasket replaced as well. Fortunately it seems to be aluminum, so it shouldn't have any issues with warping like plastic parts of similar vintage. A head gasket replacement would involve the timing belt, deck and cylinder head flatness, and a whole bunch of other issues you probably wouldn't or couldn't address with the engine in the car. You should be good without going that far.

The intake side and exhaust side valve cover gaskets are offered separately, if only one side is leaking. Once you remove the plastic cover over the valve covers it might be easier to see what and where the leak is occurring. As Daniel suggested, and you are going to be under that cover, I would replace both.