Cam seal or valve cover leaking?
 

My 1991 Lexus LS400 never has an oil leaking till the last few weeks ago. I smelled oil and saw a little smoking coming out of rear of the motor (Driver's side). I've decided that I will replace valve cover gaskets. Do I need to replace the rear cam seals on the both sides as well? Please help..:uh:.

please let me know what u find out, ive had this problem and no one seems to be able to tell me where its coming from....it comes from the rear but drips down on a loom of wiring and ends up in the front of the motor. very frustrating as i keep my car in tip top shape.

mine does that too. i was gonna change the valve cover gasket to see if it would fix it but if anybody knows whatelse it could be it would be a big help.

well i had the dealership give me an exploded view and i think there some sort of half moon shaped thing back there if i remember correctly, maybe thats the culprit. but it is very tough to see exactly where its coming from

My 95 has oil leaking on passenger side. I have been smelling it for a while. Odds are that is your issue. I removed the air intake and visually inspected both sides and found the oil residue covered in dust, etc.

Changing the gaskets is pretty involved - I have a mechanic that will charge $75 to swap them - not bad.

my valve cover gasket on that side was replaced because of this issue,it still does it

Spoke with a Lexus specialist
 

I just spoke with a Lexus specialist (Independent Lexus Service in Houston) this morning. He said that if I decide to replace camshaft seals on the both side then I would have to remove the timing belt in order to take camshaft out. Forget it....:thumbdn:

I will just go ahead and replace valve cover gaskets. I still have about 50,000 miles before I change the timing belt. (To 267K from 217K)

I will let all of you know the update. I am planning to replace gaskets tomorrow.

ok.....thx

A temporary solution is to use RTV gasket sealant and just apply enough around the cam seal so that it doesn't leak out anymore. I had to do this for a car and it worked for 2 years until I tore down the engine and replaced the seal while I was at it.

I removed the valve covers, I didn't see a camshaft seal in the rear of the motor, only front. @python-You said that you have replaced the both valve cover gaskets but still leaking from the rear?

I hope it's not plug on the rear of the head!

I checked out the Lexus parts from the Internet. I don't see any rear cam seal so I guess that LS400 don't have one. SO.......I guess the valve cover gaskets is the only answer to solve the leaking from the rear unless the plug (from the rear of the head) is leaking which would VERY RARE.

there is some sorta plug back there

i have the exploded view in front of me..i need to figure out how to post it up for u....my lexmark x5150 sux sorry. i have windows 7 64 bit and my all in one just isnt very good

well i was cleaning the engine lastnight and realized all the valve cover bolts were almost finger loose, so i tightned all of them and hopefully i dodged replacing the valvecover gaskets.

The valve cover gaskets on a V8 can be a somewhat annoying undertaking but it's manageable, just keep the parts organized. On my Jag (albeit an inline motor, not a V) there are half-moons on the rear edge of the valve cover and I'm frankly not sure why.

Oil leaking from the top end really can only come from a couple of places. If it's burning externally it's most likely that it's leaking / seeping on to an exhaust manifold or downpipe and that could be good news, as it probably isn't a failed headgasket. If you replace the valve cover gaskets, check the plug wells for oil and should replace those gaskets as well. Use an uninterrupted bead of red high-temp silicone gasket sealant on both the top and bottom surface of the gasket if you want to make a 100% guaranteed seal; otherwise you can be relying too much on torquing the bolts in exactly the right order and just to spec, and even then, sometimes it doesn't quite work.

If it was burning internally and coming out the exhaust you obviously have a different, and likely much worse, problem. If you have a leak that ISN'T burning that could also signify worse things.

If it was just loose bolts then that WOULD be a lucky dodge.