I have been noticing for a while now that oil is pooling on my lower intake on both sides of the plenum. I thought it might be coming from valve cover so I replaced gasket. It didn't help. Is it possible to have an external oil leak from the plenum? Is there even any oil in it?

The car has 270,000 miles on it an runs like a top. but the leak is annoying since it eventually ends up getting hot and smoking?

I would appreciate any insight on this

Replace the Upper Plenum gasket....while the plenum is off, looks at the hole in the plenum where the EGR stovepipe inserts......look for degradation of the plastic....if you see it melting/misshapen plastic in the walls of the hole, the plenum should be replaced, because if it further deteriorates, it will leak coolant into the lower plenum, which will then suck it into the cylinders....

At 270K miles, you have to ask yourself a question....do you plan on keeping the vehicle for awhile.....is the transmission ok? Rust problems like undercarriage, brake, or fuel lines?

If you plan on keeping the car for a long period of time, and decide to do the gasket, and check/replace the plenum, I would suggest one more step...and that is replace the lower intake gaskets while you are in there....also replace the PCV valve, and thermostat, and remove the throttle body from the upper plenum, so that you can thoroughly clean the throttle plate and bore, and also clean the IAC passageway.....also clean the pintle of the IAC valve....

Like I said, it'* more money and work, but it depends on how long you intend to keep the vehicle.......at 270K, it'* possible you could have a domino situation, where other things start to go after you pay for this work....tough decision.....

Thanks for the reply Tech II

Your right, a lot of miles. Actually I'm planning on get rid of it before transmission goes or head gasket or whatever. This car is already costing me a lot of money to keep on road. I'm just trying to fix a couple of obvious fixable problems without breaking the bank in order to sell it. If it were not for the smell of oil I wouldn't worry about it. After all , who would expect to buy a 15 yr old car with that many miles that isn't leaking something. The plenum and lower intake were replaced at at about 70,000 miles for the reason you listed. Now I may add a pint of coolant every 6 mo.

Otherwise the car is in great shape.

Thanks again, and I,ll see what I can do with that leak.