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Our '02 IS300 burst the radiator at the tank seam a couple of weeks back with my wife driving it. She stopped the car when she saw the steam and called me. i went to her with water and added a couple of quarts of water, left the cap loose and drove it home at normal temps. When I replaced the radiator I saw lots of oil on the engine but the valve cover has been leaking for some time and I thought it had gotten worse. Yesterday she drove the car and I saw a large oil puddle on the garage floor. I decided it was time to do something about it, thinking the VVTI gear o ring had given up. I pulled the covers to start the job and washed the engine down. Today I put the car in the garage, jacked it up and removed the lower pan cover. I ran the car to see If I could see any leaks from the valve cover when I saw this leak coming from behind the exhaust header flange. Any ideas on the cause? Is the head cracked? You thoughts solicited. See oil on top of exhaust flange.
Hmmm, that's a good one. It's kind of a pain to get the exhaust off this car because it has to be "fished" out once you disconnect all the bolts. Are you sure it is coming from inside the manifold outward? That's quite a bit of oil the motor is ingesting/spitting out the exhaust if so. The only thing really above that that could leak oil would be the PCV system (maybe) or the valve cover gasket. A significant increase in crank case pressure will cause the PCV system to move more air/oil around.... and potentially could worsen a leak at the valve cover gasket.
I'd see if you can prove it's coming from inside the manifold or if it's being dripped onto the manifold from above it.
It is coming from behind the manifold flange, not dripping down. I can wipe it off and watch it reappear. I have a appointment with the Lexus specialist on Dec. 5. I'll let you know his opinion.
I wonder if it's a cracked ring land. I cannot think of many reasons oil would be inside the combustion chamber. Have you checked compression? I'm definitely interested in what you find out for my own curiosity.
i have the same problem. i am taking exhaust manifold off today and cleaning the area and replacing the gasket. will let you know what i discover. what were the results of your appointment about yours?
It was a 15 mile drive to the Lexus specialist's shop. The engine was of course warm when he looked for a leak. The oil wasn't coming from that spot when he looked for it. He said the oil was coming from the leaking valve cover above it. I drove it back home, let it cool off, and washed the engine again. Then I started it up and looked for a leak. There were only small bubbles at the area. I ran it awhile and no oil appeared. I can only theorize that the oil from above had settled into the area between the manifold and head and a slightly leaking manifold gasket was pushing it back out. I know it sounds weak, but that is the only explanation I have. We had the shop replace the cam seals, VVTI cam gear, timing belt, valve cover gaskets, and spark plugs. We've been driving it for a week or so and all seems fine.
I feel like oil coming out of your exhaust in that quantity would foul your o2 sensor and cats pretty quickly, along with make the car run like dookie and smoke badly.... that's why I suggested valve cover gasket. It doesn't explain how you said it could be pushed back out after you wiped it though.
Wasn't coming out of the exhaust. It wasn't getting in the cylinder. It was coming from between the exhaust manifold flange and the head. When the head/header was cold and engine running, I sprayed soapy water at the spot where the oil was coming from and it bubbled like a leaking tire. I guess there is enough of an exhaust leak there to make it do it.
When you take the exhaust manifold off, you will see voids in the head behind the flanges that can collect oil that leaks from the valvecovers. And water if you wash your engine.
I had a similar issue with mine when the valvecover gaskets were leaking. It's common for oil to collect here even after the engine is off. When the car is driven, it tends to boil and burn and smells horrible.
There is absolutely no way oil can come out of the head in this spot UNLESS your head is cracked, which can only happen in a hard front end accident
When you take the exhaust manifold off, you will see voids in the head behind the flanges that can collect oil that leaks from the valvecovers. And water if you wash your engine.
I had a similar issue with mine when the valvecover gaskets were leaking. It's common for oil to collect here even after the engine is off. When the car is driven, it tends to boil and burn and smells horrible.
There is absolutely no way oil can come out of the head in this spot UNLESS your head is cracked, which can only happen in a hard front end accident
We have been driving the car for a few weeks now and there are no oil leaks. The shop replaced all the front cam and crank oil seals, the cam gear, the timing belt, and the valve cover gaskets. That took care of the leaks.
So is the general consensus that it is old oil from the valve cover gasket leaking? We took the header off and oil poured out of the header flange on the engine side. The valve cover gasket(s) were replaced a couple years ago and are completely dry everywhere.Thinking about sealing the valley ports since the factory gaskets have air holes punched into the metal. Any other thoughts? thanks much!
11-28-18 | 09:18 AM
Oil leak at exhaust manifold flange
