LS - 1st and 2nd Gen (1990-2000) Discussion topics related to the 1990 - 2000 Lexus LS400

Oil leak from bottom of engine

Old 12-05-16, 09:12 PM
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Hiroshi12
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Default Oil leak from bottom of engine

I hate to start a thread with such an open-ended question but here goes: does anyone out there know if our cars are prone to oil leaks from somewhere at the bottom of the engine? I have noticed over the last few weeks some spotting after the car sat for a while. Looking down from the top and along the usual places where one would find oil leaks it's completely dry. Jacking up the car slightly, I can see oil pooling on the edge of the plastic lower engine cover. Also, and this is the weird part, when the car sits level for several hours, there are one or two drops - but when the car is pulled into the driveway (slightly angled upwards)...the next morning there is a pool of oil about 3 - 4" in diameter. Ideas?
Old 12-05-16, 09:33 PM
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Banshee365
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Look at the front of the engine under the crankshaft balancer. The front crank seals like to leak with time. The other really common leak point on these engines is the valve cover gaskets. Obviously leaks up high like valve cover gaskets migrate down and pool on the bottom.
Old 12-06-16, 05:42 AM
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fixmiester
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Default Check this

Number one cause of leaks is the PS pump, be sure to check that first; by the time it works it's way around the engine, and the plastic cover, it can look very much like engine oil.
Old 12-06-16, 06:03 AM
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Hiroshi12
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Originally Posted by fixmiester
Number one cause of leaks is the PS pump, be sure to check that first; by the time it works it's way around the engine, and the plastic cover, it can look very much like engine oil.
Didn't think of that. Thank you.
Old 12-06-16, 06:13 AM
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If you're leaking from behind the front plastic cover, and the leak increases when you're at an angle, I would suspect the cam seals. Possibly they were not replaced when the timing belt was done. Assuming you've replaced the timing belt. You did not state how many miles on your vehicle. If it's anything over 100k and you've not replaced the cam seals and you're leaking from behind the plastic cover then that would be my first guess.
The power steering pump would leak onto the alternator and take it out eventually. It would not leak into and then back out of the plastic cover.
Old 12-06-16, 07:45 AM
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i would take off the cam covers and check the condition of your timing belt before you do anything else. I had to do my Timing belt due to the crank seal failing and coating the belt in oil 2k miles after i bought the car. I had 255k miles when it failed in 15' (97 model) I'm thinking it was original since most people only change the belts and water pump out during the 90k intervals.
Old 12-06-16, 04:03 PM
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Originally Posted by Hiroshi12
Sorry, I'm not an engine guy.
Not being an "engine guy" makes it hard to know, and fix, where its coming from. I would suggest checking the back of the valve covers. It might be leaking there, draining down and pooling, onto the lower engine cover then dripping off when you park on a hill. You cant see behind the engine where they usually leak so rub your fingers behind the valve cover (after the engine is cooled) to see if that's where the leak is. My old 93, and the 94 I have now both leaked there. Other then that, you could take off the lower engine cover, look up and follow the trail of oil.
Old 12-07-16, 08:11 AM
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Thanks for the advice everyone. I now have an idea of what could be causing this leak. Tbh, I'll be taking it in to my Lexus mechanic so if nothing else, I'll know if they're bs'ing me. I hope I don't end up like a coworker who spent thousands on his truck at a Ford dealer chasing an oil leak.
Old 12-07-16, 10:29 PM
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Originally Posted by Hiroshi12
Thanks for the advice everyone. I now have an idea of what could be causing this leak. Tbh, I'll be taking it in to my Lexus mechanic so if nothing else, I'll know if they're bs'ing me. I hope I don't end up like a coworker who spent thousands on his truck at a Ford dealer chasing an oil leak.
That what dealers do best, make $ .
Old 12-15-16, 09:06 AM
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Default ...update

As it turns out - the oil leak was in fact coming from the valve cover gaskets. I guess having the car on a lift they were able to see something I couldn't? Anyways, the shop wants nearly $900 to do the job because "it's a lot of labor on these engines". If I was a total noob I would think "$900 for valve cover gaskets? No way, Jose" but from my experience with the starter replacement 2 years ago they're probably not that far off the mark, right? But that price...ouch!

Last edited by Hiroshi12; 12-15-16 at 10:11 AM.
Old 12-15-16, 09:17 AM
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I think that's too much for valve cover gaskets but it is getting a bit cold to be working on cars outdoors.
Old 12-15-16, 09:30 AM
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Originally Posted by sha4000
I think that's too much for valve cover gaskets but it is getting a bit cold to be working on cars outdoors.
Think I would lay down a catch pan/newspaper for the winter and tackle it come spring. Valve covers can't be that hard.
Old 12-15-16, 09:32 AM
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Originally Posted by Hiroshi12
As it turns out - the oil leak was in fact coming from the valve cover gaskets. I guess having the car on a lift they were able to see something I couldn't? Anyways, the shop wants nearly $900 to do the job because "it's a lot of labor on these engines". If I was a total noob I would think "$900 for valve cover gaskets? No way, Jose" Although from my experience with the starter replacement 2 years ago they're probably not that far off the mark, right? But that price...ouch!
you might get another couple shops to quote you a price.
Old 12-15-16, 10:10 AM
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Well, I'm in San Diego so I don't feel that the weather is a factor but shopping around for a better price is definitely good advice. And like you guys said, valve cover gaskets shouldn't be "that hard" but then again, a starter shouldn't be either but we all know how that goes with these cars.
Old 12-15-16, 10:35 AM
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The itemized amount for the valve cover gaskets on mine was $632. Oil leaking from here isn't a critical running issue, just messy. They will leak more and more as those hard parts allow more oil to get past.
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