I've been looking around at a few mid to mid-high mileage LS1's with 6 speeds...from what I've gathered from a few people and my own knowledge, here's what I KNOW i need to look for...

Engine Idle when hot
Oil Pressure at idle when hot
how it sound when it first starts up
quality, color, and amount of oil. (good oil they're probably trying to hide something) color and amount indicative of wear?
ease of shifter (6 speed), does it grind when shifting quick
any noises from the rear end

anything else I should look for? thanks a ton in advance guys...

 

-make sure the shifter doesn't pop out of gear, especially in 3rd.
-check for obvious leaks, you can ignore the rearend b/c it WILL leak around the pinion, period.
-slipping clutch, maybe do a WOT run from a low speed start in 4th to test
-holes inside the car, dash, console, etc., that arent' supposed to be there.
-I personally went for a non-moded car, better chance of not being beat on.
-excessive rubber under the rear wheel wells

 

Mine doesn't leak.

Quote:

-check for obvious leaks, you can ignore the rearend b/c it WILL leak around the pinion, period.

 

Id do all of this and then the regualr crap you might look at before buying a car. Make sure you can listen to it during a cold start up. check the inside of the coolant tank to check for contamination. Id take a look at the shocks, if theyre orangeish reddish stock decarbons, they were bad after the first 20k miles. look and the throttle blade and see if theres oil on it or take the pcv valve out. Id autotap it too.

 

Ask if he has replaced the window motors (power windows) and if not, see how fast they go up when near the top of the track. These will also go bad

 

It will, just give it time

I forgot about the window motors.

 

It may seem to you that they all leak, but trust me they don't. I've got 3 and none of them leak at all.

 

i am lucky enough to have a 98z28 with 98k and i have no problems with it. doesnt burn oil doesnt leak fluids no piston slap, theres really good cars out there with high miles just gotta hope you get the good one. i say the only thing my car needs is a new pass. side power window motor its getting pretty weak is slow compared to my driver side one. I would get one thats stock and not modded.