omar6

Hello!

I have an 04 LS 430 with ~181k miles that broke down in April 2023 after only two short but sweet months of ownership. First had a ticking noise from engine (but no CEL), then a misfire and a VERY rough engine idle randomly one day and after taking it to the dealer the misfire spread to each and every cylinder. After a failed first attempt issue was diagnosed as a head gasket due to moisture in the cylinders (seen through borescope).

As I have been doing this job I found out this has all been done before (half moons have a lot of assembly sealant, camshafts had paint marks to align them after being removed and put back, etc...). My worry is that the issue may not just be the gasket, therefore I want to check my heads for straightness and check all my valves as well. Unfortunately I have no idea how to do this, and do not know any mechanics or knowledgeable machine shops in Austin TX that can do this (if you do please let me know).

This project started as a learning experience for me first and foremost, so I now decided to try this myself! I have the factory service manual as well (not very helpful sometimes). Any advice on how to do this? Also, is there a way I can confirm the head gasket failed and not the actual cylinder head/block? I still have to clean up the gasket to look for any obvious failure points. Lastly, any advice on what tools to get? I know I need feeler gauges to test straightness, but is there anything else that would be useful?

For parts, other than an engine overhaul kit with gaskets, will I need new head-bolts? Should I also replace the camshaft bearing bolts?

Any way I can clean all the parts I have (heads, valve covers) without any industrial machines/equipment?

Last question, (I promise) how can I rewire a broken connector on the wiring harness? I accidentally ripped out my drivers side O2 sensor 1 connector trying to disconnect it (picture attached). Can't seem to find a new connector online.


Broken connector (the one attached to the wiring harness)


I did one oil change, light suspension work and brake pads (took me six hours to do) before this job, so I have come a long way but still have a lot to learn! Any video tutorials or threads you can send my way would be greatly appreciated! I have watched this video from Mike's Garage on his top end rebuild which has been great but doesn't show the actual process of checking valve clearances and such.

LeX2K

Get yourself a precision straight edge, spec is basically slightly above zero or 0.002 thousands. You will need the heads checked for cracks that may be the original problem that the previous owner encountered but assumed it was gasket failure. Hopefully someone in your area knows of a good machine shop they are hard to find. There are dye kits to check for cracks but from what I've seen they are hit and miss.

Connector is very easy to repair compared to the rest of your project don't worry about it for now, you'll either need a new housing, new pins or both.

I clean cylinder heads with oven cleaner and dish soap works great. Just make sure you get all the oven cleaner off and air dry the head as quickly as possible. Don't use a wire wheel on any part of the engine except to clean the valves. Head bolts are not 1 time use as some thing, they can be reused if they are not stretched beyond spec. What matters far more is the threads in the block must be 100% clean and pristine. Cam bearing bolts don't need to be replaced, same for main and rod bearing bolts assuming they are not damaged.

05ls430518

iTrader: (1)

Before you buy anything make sure your heads are not warped/cracked also check the block. Did the cars temp gauge get into the danger zone at all?

dwoods801

Wow! You don’t see many 3UZ’s blow a head gasket. I would just find a used one and throw that in. You can spend a lot of time and money rebuilding an engine and you’ll be putting it in a 20 year old vehicle. You can find a hood used one that will be every bit as good as the rebuilt one.

weldthedif

i would recommend finding a used engine from a known good (wrecked) car than trying to fix what some other mechanic botched.

sorry this happened to you man

dwoods801

U can find used 3UZ long blocks for less than $1000. You can use either model of 3UZ long block if you’re going to be keeping your transmission, accessories and emissions control equipment. Rebuilding your original engine will probably cost you double that. Depending on what you replace and what you have machined. The problem is you can’t really do half an engine rebuild without gambling. Maybe you just replace the head gasket. It’s almost certain that the head and/or deck are warped. So if you don’t send it to the machine shop, you could blow another head gasket after just a few thousand miles. If you get the block decked and have the heads milled to make sure they everything is perfect, then you will be spending a lot of money, you’ll be increasing the compression ratio, you’ll be spreading the distance between the two heads, so that can make the intake manifold fit poorly. If you need to replace any pistons that are damaged then you’ll need to replace the bearing with it. It’s just a lot of expense and there is no benefit and not really any guarantee. At least if you buy a used motor it’s going to have a 30 day or maybe 1 year warranty. You could get a complete 3UZ with transmission that’s ready to drop in and just hook it up from a JDM importer for about $2000. And they usually have around 50,000 miles. Can’t beat that