1994 Es300 Smoking And Power Steering Fluid Disappearing

Gregzilda · September 9, 2008

I have an 1994 ES300 that I bought new. Recently it suddenly started smoking badly from the exhaust. The smoke did not appear to be exactly white or blue but slightly blue. I have smelled both burning oil smoke and the sweet smell of anti freeze burning. This was neither, it smelled like hot transmission fluid. The transmission fluid was a little low but then I noticed that the power steering fluid was a bit lower than usual. I did some research and found that a little known but common problem is that the "idle up valve" or "air regulator valve" as it is sometimes referred to, on the power steering pump has a tendency to allow power steering fluid to bypass and be sucked up into the intake plenum. The one I found mentioned was part #17630-16040 on an LS400. My ES does not have the exact pump but does have a power steering fluid filled line coming from the rack and pinion, vertically, near the power steering pump area and has an aluminum piece screwed to it with two vacuum line hoses going to the intake plenum. It appears this "valve" may serve the same purpose. The trouble is I can't find out the name of the item, pictures or descriptions of any kind. While I will admit I have had valve seals go bad and give similar symptoms more slowly over time, this episode struck me as unique. The car runs fine, does not overheat, isn't low on anti freeze nor is any anti freeze in the oil. I intend to do a compression check, ect. I also intend to perform a valve cover gasket replacement as the pcv on the rear bank fell apart into valve cover hole when I tried to remove the hose from the pcv. Prior to that, when I removed the pcv hose from the right bank to the intake hose it really didn't change the idle and appeared to have slight traces of oil inside. It could be clogged and drawing oil in here also I suppose. Any ideas.......pics.......manual downloads.... would be appreciated.

N.C.O. · September 10, 2008

The valve that you had found is indeed the Idle Up valve, it is mounted on the power steering hose behind the engine on the firewall, two hoses attached to it, one goes to the intake plenum and the other one connects to a port on the throttle, if I remember correctly. Pull the hoses off at the valve, both should be dry, if you see any sign of oil either inside the hose or the valve, you have found the cause of the smoke from you tail pipe.

N.C.O.

Gregzilda · September 11, 2008

The valve that you had found is indeed the Idle Up valve, it is mounted on the power steering hose behind the engine on the firewall, two hoses attached to it, one goes to the intake plenum and the other one connects to a port on the throttle, if I remember correctly. Pull the hoses off at the valve, both should be dry, if you see any sign of oil either inside the hose or the valve, you have found the cause of the smoke from you tail pipe.
N.C.O.

Thanks N.C.O.. If the valve needs replacing would it be better to remove it at its attaching point on the power steering rack or at the end of the tube where the valve connects? It appears to be pretty snug against the firewall. I guess I would lose less fluid if I took it off the top. Also, It appears the intake plenum must come off to replace the rear bank valve cover gasket. If this is true, and I intend to replace both gaskets, I could just remove the plenum first. Regards