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

Lower valve cover replacement

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Old 07-21-18, 01:33 AM
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99LSprobs
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Default Lower valve cover replacement

so after visiting multiple mechanic shops I’ve had multiple mechanics tell me that my lower valve covers are leaking (losing quarts of oil every couple hundred miles) quoting me at ridiculous prices I just wanted to know what was wrong I’m not actually get them to do anything so I could fix it myself. Is there any type of special tools I need for this fix? First time doing anything like this... thanks
Old 07-21-18, 10:08 AM
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oldskewel
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These tend to loosen up over time as the rubber gasket dries out. The first easy thing to try is to just re-torque the bolts. They are probably 10mm hex head, and many will be deep in there so you'll need socket extension, and probably to remove a few items to get access to some of them. Test the most accessible bolts first - see if they turn easily.

Look up the correct torque value - it is probably not much, in the 10 Nm range, I'd guess. Usually with bolt torque you want to get it as tight as you can without breaking the bolt. But here you're also concerned about getting it so tight that it deforms the gasket or valve cover. But my guess is that when you put a socket on it, you will find some of them completely loose.
Old 07-21-18, 01:09 PM
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4 hours later here I am, yes I’m slow. But I wanted to be sure, I saw what you meant by the bolts being loose, I could turn them easily with my fingers! I cleared up all the oil everywhere under the car, and I mean.... everywhere. No oils leaks on my drive way yet! Thanks for input
Old 07-21-18, 11:51 PM
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Awesome! So it sounds like what you did definitely should have improved things. Hopefully enough to fix it.

And good to go slow. If you have not worked much on the engine, there are probably many vacuum hoses and plastic connectors, etc. that are brittle with age and heat. You may break some and know about it, or break something to cause a vacuum leak and then have to track it down.
Old 07-22-18, 12:14 AM
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Indeed, but I left the engine running for like 45 minutes and no signs of anything yet
Old 07-22-18, 08:30 AM
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Be sure to keep us updated.
Old 07-22-18, 07:56 PM
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dicer
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Cool

I'm at a loss, I never knew there were both upper and lower valve covers, that would make 4 covers all together. So is that special with the 99 model years? So do you access them from under the car? The uppers are of course the normal ones at the top of the engine right? I'm curious what those valves do that are under the "lower" valve covers? So then there are of course extra cam shafts down there as well to make them work. Wow, I really need to see some pictures of this, but I would want to see the engine out of the car pictures to get a good grasp on the location of those "lower valve covers". Thank you and looking forward to some photos.

Last edited by dicer; 07-22-18 at 08:02 PM.
Old 07-22-18, 10:22 PM
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oldskewel
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LOL. I assumed he meant the leaking was coming from the lower edge of the valve covers. But yes, maybe he's got a W16 in there or something.
Old 07-23-18, 03:05 PM
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dicer
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I'm still waiting for the photos. Even a description from the shop manual would be nice to. I just never thought the later Gen's were so cool and had all that fancy stuff.
Old 07-23-18, 03:55 PM
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Sorry for no response, busy with college and all, when I get back to my laptop I’ll upload the pics!
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