Tescrash

Hey guys, first time posting here. I just traded for a '91 LS400, and it's pretty rough, but I've already fallen in love with the car. One of the previous owners has riced it out to Osaka and back, and I'm trying to get it back into presentable shape for a daily driver. The car has a significant oil leak, and the previous owner told me that he thought that the oil pan gasket definitely needed changed, as the car is stupid low on some Megan coilovers, and at one (or several) points the pan has touched the ground. So, I pulled it into the shop to take a look at everything and found some things that I expected: the lower ball joints are practically falling out (as I said, stupid low), and the oil pan has indeed touched pavement a few times. What I did not expect to find was a serious oil leak coming from the top rear of the engine...so, after looking around, I traced it to the back of the head. I felt around...and noticed that I could stick my finger INSIDE the head. I wasn't aware that these heads had plugs in the back, but I felt the other side, and sure enough, the plug was still in it. Neither side had the Y-shaped plate that goes behind the plugs, so I'm assuming that that is why it came out. My questions are:
1. Does anyone here know the part number for the plug, or for the Y-shaped cover for the plug? I've searched Lexus Of Atlanta's parts website, and I believe that the plug is number 11188 on their cylinder head diagram (I'll try to post a picture of the diagram), but I can't find the cover plate anywhere on their website.

2. Has anyone here replaced one of these? Is it possible to do with the engine in and everything on it? I'm assuming that the plugs just kind of pushes in, but I'm not sure if it requires silicone or something like that. Also, do you have room to put the three bolts through the cover into the head?

If there is a breakdown on the forums on how to do this, I apologise, but I haven't seen anything in my searches. Thanks for your help in advance!
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Tescrash

Can't get the picture to upload correctly for some reason. :/

sha4000

iTrader: (1)

South Atlanta does not even show diagrams for the 91 just 95 and up. This is the best site when you have to do any work on your car.
​​​​​​http://www.lexls.com/

Tescrash

Huh. Maybe they're just showing the wrong diagram. I looked up parts for a '91 and it showed me that one. I wasn't able to find anything on lexls either. Does anyone here know how the cap seals? Surely it has to have some kind of seal....It can't just be that plate holding it in.

Banshee365

Are we talking about the fully circular plug or semi circular plug?

I think dicer has a car that one of the plugs was missing on the back of the head as well. When I get to a computer I'll look at some diagrams to see what you're looking at doing.

Tescrash

Thanks man. As soon as I get off of work I'll look, but I believe that the plug is fully circular. I'll get a better description of it.

Banshee365

The part number for the full circular plug is 11188-62010. It is the same part from 1990-1997. FleaBay has several listings if you search with that p/n. I can't speak personally for sure on if the plug can be installed without removing the rear bearing cap. I can say that the factory manual says to install the plug prior to the bearing cap. The bearing cap is also resealed with a very very thin layer of FIPG prior to install. You will need an accurate in/lb torque wrench to reinstall the bearing cap but other than that it is a breeze. There are sealing washers under the bolts at the front and rear bearing caps that Lexus say's to replace each time you remove them but you would probably have good luck reusing them. Put a very small amount of FIPG on them if you are worried.

On a 96 motor I have in the garage the passenger side plug is held in place with a bracket solely designed to do just that. I imagine the plug is in there pretty good just from the pressure from the bearing cap but there is a bracket to keep it in if I loosens up. The driver side on this engine also has a bracket that holds it in but it's part of a hard coolant or fuel line. I think it's a fuel return line by looking at it without anything hooked to it.

What part of TN are you in? What I would recommend doing is searching local u-pull-it yards in your area for LS400's. While a new plug may be best a salvaged one would probably do the job fine as well. This way you can see how it all comes apart and goes together on a junkyard car before touching yours. It's alway's a great way to go if you are unsure how things come apart.

Tescrash

First off, thank you so much Banshee. The part number alone was a huge help, not to mention the other info.

I wonder why they recommend installing the plug before the cap? Doesn't look like it would interfere with anything, but who knows. It's no big deal though, I have a in-lb torque wrench.

Actually my local Pull-A-Part has 2 first gen LS400s and 1 second gen. I work crazy hours, but I'm going to try to go up there some time this weekend. Hopefully I'll be able to get both caps, both plates, and some other things that I'm needing.

Thanks again for the help!' If I run into any problems, you'll probably hear from me again. xD

Banshee365

By caps you mean the plugs right? DO NOT change your cam caps. They go with the cylinder head. I'm almost certain you're talking about the plugs but I just want to make sure.

One reason that the bearing cap may need to be removed is if the plug has a groove that interfaces with a lip in the bearing cap or something. I'm not sure if that's the case as I've never needed to replace one. Your's isn't the first I've heard of one falling out so I imagine they're not in there all that great.

HELP DICER!!! You're the man with the experience on this one.

When you've got your parts I'll help provide you with some info on sealing the bearing cap as well as the torque spec for the cap bolts.

python

iTrader: (4)

http://www.rockauto.com/en/catalog/l...lar+plug,10426

YODAONE

See attached Lexus Exploded Parts Diagram depicting cylinder head and valve covers.

Contact Lexus for direction. At least you have the same parts diagram they use to better direct your parts counter person

dicer

The one I did some years back, I figured it was blowby that caused it to come out. It was the driver side LH. I did remove the cap to install the new one and since it was the step kids car at the time and did not want to deal with it popping out again I put a small touch of epoxy on the cap side to help keep it in. Not recommended but at the time its the last thing I wanted to have to work on. It stayed in and all leaks fixed. Oh and at the time I was NOT an LS400 enthusiast, and wanted to rip out that 1uzfe and put a chev in it something easier to work on. Yeah ME. This is like one of those believe it or not deals.

Tescrash

Just an update:. I didn't forget about the forum, lol. I found a nice UCF10 parts car for $150 (no motor or tranny), but the guy had a 1UZ that he told me was bad, so I got both plugs just in case. I'll be putting it in tomorrow, and I'll try to take pictures. It seems like this may be something of a design flaw in that the passenger side plug has the nice big three pronged plate covering it, but the driver's side doesn't really have anything to keep it from coming out except the compression from the cap with the two bolts. There's a small bracket behind it that holds a line, but, at least on the motor I saw, it doesn't even touch it. Obviously the motors build enough pressure in the head to blow one out over time, so I'm going to attempt to fab up a simple keeper of some sort for the plug as well tomorrow.