YLK

A super nice mechanic checked the OBD code, looked under the hood and found a hose (near the purge valve) had come loose.
He connected the hose back and cleared the OBD code. No CEL problem since.

I bought the purge valve but haven't installed it yet. Should I replace it anyways (since it's a 1999) ?

shwalker07

I would leave it alone if you do not have any current OBD codes or problems. Sometimes when you start moving things around you will end up with more problems that you originally expected such as rusted bolts/cracked hoses or other issues you may run into while working on your original problem.

YLK

Thanks, will leave the old purge valve alone for now then.

Also, the 1999 Lexus GS400 (at ~150,000 miles) is due for timing belt replacement. Wondering whether to replace thermostat/gasket, radiator/hoses and oxygen sensors at the same time. Trying to decide between Bando 6PK2240 vs MITSUBOSHI 6PK2245 Serpentine Belt. And, since the 1UZ-FE is an interference engine, is it safer to let the dealership do the timing belt replacement ?

RamAirRckt

I did my first timing belt on my 2GS4. Not a problem except the water outlet was a nightmare to get out, broke it trying. So my 1UZ has a 3UZ new design water outlet. If you know your way around an engine bay, and are confident in your work, go for it. If not, let someone who is work on it. Its really a pretty easy job. Book time is 4 hrs I believe. But if you have no issues like I had and have all your tools ready, its an hour job.

I did it first in 4 hours, had to take it back apart because I got the left cam off one tooth and the ECU complained. Took 2 hours second time. Was pretty easy really.

YLK

Thanks, will just let a reputable mechanic (not dealership) handle it then.

RamAirRckt

Its not a bad job (like an Audi A8 D2 where you have to remove the front end to make room, book time, 12 hour job!). Lexus did a great job of making it overall pretty easy to work with.

I'm starting to plan my next timing belt swap soon, probably next spring.

I likely won't do water pump this time, mainly because I'm comfortable getting in there to get to it if it needs it, but I did the first time to be safe. Running Toy Red or Pink antifreeze will keep the waterpump healthy for a long time.

wmj259

I have checked all the hoses up front for my ES. Even did the brake cleaner spray trick and see now affect from that. My next assumption would be the charcoal canister.

YLK

Thanks, I bought the car used over a year ago so I'm not sure whether it was well-maintained or not.
Since the mechanic will be doing the job, I may as well replace the water pump. Not sure whether to
replace the radiator/hoses at the same time. Does the radiator need to be removed when replacing timing belt ?
If so, I may as well replace the radiator/hoses as well.

YLK

Thanks, but I think the disconnected hose (near purge valve under hood) caused the CEL problem. Reconnecting fixed it.

What's the "brake cleaner spray trick" ?

RamAirRckt

Yes, radiator comes out.
Generally the procedure is: (there is a more accurate guide on here in the FAQ, but this is off the top of my head)
1. Disconnect battery, Pull air cleaner assy up to throttle body
2. Drain and remove radiator and fan assy and upper radiator hose. I did break my 3 bottom fan shroud bolts due to rust. Never bothered fixing, its still stable in there. Sure makes taking it out lots easier now!
3. Remove harmonic balancer (remove bolt, slide off, it isn't pressed on in a belt engine)
4. Remove alternator and power steering pump bolts, leave there, don't remove hoses
5. Remove water pump outlet (not easy on mine, may not be bad on others, I do have 302k miles...)
6. Remove timing belt covers. Line up timing belt marks, mark pulley to belt to engine in a few different places on the same pulley to make it easier later)
7. Pin timing belt pensioner (don't remove until you do! Its hell to get the pin back in if you don't first....) I did replace mine, but honestly my friend at Lexus has never seen a failure in 29 years.
8. Pull belt, install new belt.
9. Reverse order.

Its more scary the first time, but once you have done it, Lexus/Yota did a great job on this design. They used their HEADS!

tmf2004

iTrader: (15)

I've had the same code P0446 for months now and i just clear it from time to time. I also get a exhaust type carbon smell from the engine bay that comes and goes. Could that be a catalytic converter going bad or exhaust leak? My mechanic says the same thing that its the charcoal canister in relation to the code that pops up.

YLK

I smell gas fumes on cold start sometimes. Not sure yet but I may have found the solution.
In my case, I used to have problems keeping the gas pump handle locked ON (at Costco).
The handle would keep popping to OFF until I learned to angle the feed more vertical by holding the handle up higher.
No more popping to OFF and no more gas fumes on cold start so far. Keeping my fingers crossed.

tyson rust

yes that fixed the 1st issue

lyonkster

These three codes point to a problem in the evap system. It's either not sealing when it should, or not purging when it should. Before messing with the three valves, look at the evap hoses. On our ~15 year old cars, they are usually hard as a rock. I found two in the engine compartment that were broken in half (completely), which caused the codes. I replaced all the evap hoses under the hood, to stop chasing my tail again. Haven't had a code since.

Failing that, check the three valves using the standard procedures. Finally, if that's not it, get a cheap smoke machine and check where smoke comes out of the system.

mate01

Had the same issue, it was the rollover valve, get a smoke test to be sure.