Oil Leaking In To Exhaust Guide Valve

[jarvis]

what would cause this? and how expensive is it to fix. i cant afford to put the car in the shop

[gserep1]

what would cause this? and how expensive is it to fix. i cant afford to put the car in the shop

This is caused by WORN valve giudes. The questions would be,

1. How often has the oil been changed during the engine's life?

2. What kind of oil has been used?

3. How many miles does the car have?

The GS200 and GS400 /430's are RELIABLE engines capable of HUNDREDSS of thousands of miles with no problems. Proper care is the key to long life. Many of us are 2nd and 3rd owners, so in the absence of records, we often have NO clue how the car was cared for prior to our purchase.

On the Lexus engines, worn valve guides require replacement for proper repair. There are some "additives" that TRY to swell the existing seals, but if no seals are present, then nothing can repair the engine short of removing the head and having the valves reground and new valve guides installed.

You save themost by removing the head(s) yourself and have a machine shop do the machine work for you. Then you just replace the head with new gaskets and seals.

The dealership is the most expensive, followed by an independent repair shop. If the mileage is close to a 90,000 mile interval..(90, 180, 270), then do the timing belt, tensioner and berarings while the head is out. Those parts have to be removed to gain access to the head anyway.

GOOD LUCK in your repair.

[rickgus]

Sure you don't mean valve seals? Not guides?

I keep hearing about this issue on these cars. I've started doing the one thing I swore I'd never do, use synth oil, in hopes of dodging this bullet. My car has low enough miles, and appeared to have been very well taken care of by the PO. So, keeping my fingers crossed.

[jarvis]

Sure you don't mean valve seals? Not guides?

I keep hearing about this issue on these cars. I've started doing the one thing I swore I'd never do, use synth oil, in hopes of dodging this bullet. My car has low enough miles, and appeared to have been very well taken care of by the PO. So, keeping my fingers crossed.

yes i meant valve guides. its throwing off a po430 code and ive already replaced the cats and the o2 sensors. thats the only left it could be

[SRK]

Tell us how the O2 sensors have thrown that code because of bad valve guides. I'm interested.

[jarvis]

Tell us how the O2 sensors have thrown that code because of bad valve guides. I'm interested.

if its a bad o2 sensor its telling the computer to add more fuel causing it to run richer than it needs to. and the unburnt fuel is contaminating the cats causing the o2 sensor to think the cat itself is bad then it throws the po430 or po420 code. At least thats the way i understood it to work. if im wrong please correct me.

[SRK]

It's an O2 sensor. O stands for oxygen, which is what it detects. It doesn't detect fuel, or oil.

The sensors can be scanned while in operation to confirm that they are working properly. If they are, then the problem is elsewhere - they produce a code when they are either faulty, or operating out of range in an attempt to correct a fuel control problem, or in the case of the post cat sensors, when they detect excessive variation in the oxygen content after the cat.

You don't have bad valve guides. Certainly having someone follow your car and declare "bad guides" is no diagnosis worth listening to.

Get the engine properly diagnosed. That's what OBD is all about.

Only the precat O2 signals fuel trim. The postcat ones monitor cat function. That's their job, and it sounds to me like they are doing it.