LSJ reliability past 120K miles (motor swap or not)
 

Story time! So I posted awhile back about a clutch because I am getting chattering and pedal vibration when downshifting and if I push the pedal fully in when upshifting. For a while I decided I was going to get a new or used car. I cannot justify 400-500 a month when I do love driving this car. The prospect of replacing the motor with the clutch came up as it seems the clutch job already has the car apart. I would like to stay on the M62 for now as it seems "fast enough" right now and I dont want to go turbo and grenade my transmission. The current motor has 120K on it and is not showing any outside signs of weakness other than there is oil build up around the valve cover on the passenger side. Not dripping or anything, but it has built up. As far as I know, I have GM stage 2, dual pass, front mount zzp HE, shorty header (might be pacesetter), exhaust, and cut out snorkel on the airbox. Not sure what else as it was bought used from a dealer.

Anyways, I have money right now that I might not have later. The current motor would need new water pump and timing chain at a minimum (which I would have to buy for the shortblock too) along with the new clutch. Probably have the head rebuilt while I am at it if is that time. I was thinking about doing a compression/leakdown test, but that is like 20% the cost of the LSJ shortblock on ZZP. This car will be my daily driver, so putting money into it now and driving for another X amount of years makes sense. I would also be adding a few more things exhaust wise, opt b, mounts. Main question is, should I look into replacing the motor or should it be good for awhile? Only maintenance I have really been doing is regular oil changes with mobil1. There will probably be more posts after this related but going into other details.

Get yourself a cheap compression gauge and see what kind of compression you currently have. If its ok I would just do the the chain and water pump. No need to spend money on a short block if you don't need it. Going over the head is a good idea.
It all comes down to how long you are going to keep it.

as long as it's been taken care of there's no reason to swap it out. Heck i didn't even turbo my car till i was over 200k.

I bought an LSJ that needed an engine. However, it was due to the PO's mechanic being drunk and breaking a piece of the block the timing chain guide goes into. He also tried to RTV the HG surface...but that bitch still ran.

It had 153k on it.

chassis has 177k on it now, original transmission and everything else. and i Put a used engine in that had 100k on it. it runs fine. no reason to think you cant get over 200k as long as its maintained well. LSJ engines are stout.

if the water pump is not leaking don't mess with it

I appreciate the real world examples. I did look at a few threads before this, but it was more opinion than anything. The only reason I was thinking about the water pump is that about 18 months ago I bottomed out the front in a drainage dip leading into a steep incline. It blew out the radiator, condenser, and HE. It was all replaced and was running in the 180-190 range during the winter, but here in Vegas during the 110-115 summer it would approach 230-240 on the highway doing 70. I changed out the thermostat twice as it was stuck open and throwing a code. I have read on the forums that 230-240 is normal but it scares me. Unfortunately I can only compare the temps to when I was in Albuquerque and it never seemed to top 190 unless stopped in traffic it would creap up to 210 or so with the A/C off. I thought maybe something might have struck the impeller on the pump when everything broke.

my car does the same thing

I replaced the water pump and resealed it when I did the engine

on 100+ days, the coolant would hit 225 or 230 while driving on the highway.

leemanfor, so the new water pump fixed the issue or still gets hot?

nope. that was after a new waterpump, new thermostat, new timing guides etc. New coolant, new radiator also.

You prob had air in the system. The LSJ cooling system is kind of a pain in the ass to bleed.

I'm at 145000 miles. Changed the timing chain tensioner when the new one came out. Always used full synthetic oil and a good oil filter. You'd be surprised at how much abuse an IC engine can take.

yeah i just swapped the thermostat on the wifes LSJ and it was a pain to bleed. it had one major air bubble, and then another one a month later.

mine bleeds itself. never been a problem