toytrain13

There is a REALLY NOXIOUS smell whenever I cold start my 2002 ES300. It's a really strong burnt chemical smell. NOT a sulfur dioxide smell. It goes away after a couple of minutes, but it pollutes the entire garage before I can back the car out. The smell is not present if I restart the engine while it is warm. This has been happening ever since I got the car three years ago. I had been putting up with it, but now my wife won't go near the car (until the smell dissipates)!
There are no instrument warning lights coming on when this happens.
Can anyone tell me what is going on?

speedkar9

You might have leaky valve cover gaskets causing oil to pool up on the exhaust manifold overnight. It'll smell for a bit until it burns out, and you won't smell it much when driving.

Get some engine degreaser and a toothbrush and give the engine a good degreasing to see pinpoint where the leak is coming from.

toytrain13

Thanks SpeedKar9- But the smell is definitely coming out of the tailpipe!

mmatheny

Are you SURE it's not sulfur dioxide? The cat could be bad.

PFB

Its likely an Exhaust or Manifold leak which than closes up as the exhaust heats up.

Phil

BDSL

All engines run rich during cold start....the smell of gasoline / exhaust.
Don't start your vehicle inside an enclosed garage. Open the garage door.
Start the engine and drive away immediately and gently until engine reaches operating temperature.

Hayk

iTrader: (1)

I've been trying to figure this out for the past 4 years, since I got the car. Every mechanic I've visited has said that there is no exhaust leaks they can see. I replaced the valve cover gaskets when I got the car, so that is out of the question. Both Oxygen sensors have been replaced with the correct Denso units, so they're working well. The down/y-pipe has been replaced with a Walker unit (terrible decision on my part), so the catalytic converter is good. Judging by the condition of the original y-pipe, the manifold converters look good as well. I also recently cleaned the engine.

I have a few theories that I have yet to confirm, but here is what I think is happening:

1. I have leaky injectors that seep a little bit of excess fuel into the cylinders, when the engine is shut off. This results in excess fuel on cold starts, which adds to the smell. If the engine is warm/has been running, this symptom will not be apparent.

2. There is a problem with the ECU/sensors which is throwing too much fuel on cold starts. I have monitored my engine with a live OBD2 reader and have noticed that my car runs rich on cold starts, but nothing out of the 10% Fuel Trim norm. (The check engine light will come on if you go over the 10% threshold on either bank)

speedkar9

Have you checked your flex pipe for leakage?

toytrain13

Thanks for your posts, guys. I took the car to a Lexus-friendly mechanic and he determined that there is a leaking camshaft seal. I neglected to have those replaced when I had the timing belt replacement. My Bad!

toytrain13

Can anyone suggest how many hours labor it would require to replace the camshaft seals? Should i have the water pump replaced at this time also? (At 35K, in January 2013, the timing belt , accessory belts, crank seal, and idler pulley were replaced. The water pump was not replaced, but looked okay- no leaks). Should I have the dealer replace the camshaft seals (and the water pump)- rather than an independent shop?
Thanks for your help, guys!

BDSL

To get to the camshaft seals, the timing belt needs to come off. You are looking at 3-4 hours.

BDSL

Leaking camshaft seal doesn't cause a NOXIOUS smell during start up.....

PFB

Agree with BDSL. With the symptoms you originally described, the dealer's diagnosis makes no sense. You may indeed have a leaking Camshaft Seal, but that would not cause a noxious smell only on start-up when cold, and only for a few seconds.

I still think you have an undiagnosed Exhaust related leak, as per my original reply to you.

Phil

lostape45

I was going to comment on that too because the oil leak at the cams would most likely not even get close to dripping on the exhaust...

I would suggest an exhaust leak too, check around with your hand under the car after a cold start and feel for air flow around the gaskets in the exhaust system.

PFB

Better yet, when you start your car cold, block the exhaust with the palm of your hand. A leak should become self evident.

A helper looking under the car, and listening under the hood at the same time would be good.

You can also try dripping a few drops of motor oil on the front manifold, as it heats up. See if you get the same smell that you are complaining about. If its different, than its not caused by leaking camshaft seals.

Phil