donor motor questions
 

the auction donor i bought (230k) didnt seem like the previous owner kept up well at all, has lot of leaks it seems and the temp gets to about 235 (low coolant light comes on, although it seems full, no coolant in oil.) im definitely changing knock sensors, intake gasket, valve cover gaskets and o rings, thermostat and housing and water pump (because of hot temps its reading), rear main seal, spark plugs and wires.

i own 2 of these ls trucks (2002 avalanche and a 2002 sierra), my sierra has just hit 200k and always reads 60 psi at idle. my avalanche always reads 40 psi, as does my new donor truck. is this a concern or should i also add an oil pump to the list? i REALLY didnt plan to do all this, but i dont like these oil leaks so its a must. knock sensors is just prev. maintenance (changed them on my sierra not long ago), and obviously the thermo and water pump due to apparent over heating. so now this oil pump has come to mind, and i know the timing chain is right there too...........where should it end?? lol

Re: donor motor questions
 

Have you done a compression and leak down test?..

Re: donor motor questions
 

nope it runs pretty good though and doesnt smoke...i even drove it about 10 miles back to my house

Re: donor motor questions
 

I think you answered your own question. You said the motor wasn’t kept up well. You’re going through the motor and changing things, so an oil pump is good insurance plus easier to change with the motor out. You mentioned o-rings, so I’m assuming you mean the pick up tube o-ring. If that’s not what you meant, add it to your list.

Re: donor motor questions
 

meant the grommets in the valve covers, but i have a new pan with the swap that comes with new pickup tube and o ring, so thats already getting change. i don't mind changing the pump, but im unsure on the timing chain. they seem a little scary to mess with

Re: donor motor questions
 

Timing chain is no big deal. Just line up the timing marks, unbolt the cam sprocket and put the new chain on. Use loctite on the cam bolts.

Re: donor motor questions
 

To make it easier to change the timing chain, back off all the rockers to lesseb the load on the lifters/cam....

As mentioned, changing the chain is not a big job, especially when you have it apart to the extent you have listed.

While you have it apart, suggest you pull the rear seal housing and swap out the barbell ...its in a port in rear of engine and seals off the oil flow out of the filter into the engine....

See this video on youtube

https://www.youtube.com/watch?v=4Hi9XMQ1S_4

Remember to clearance the oil pump when installing it....

:chevy::chevy::chevy:

Re: donor motor questions
 

I 2ouldnt worry about oil pump my tahoe had 369k when trans went with the previous owner they gave it to me it still had 40 pounds of oil pressure at idle weekend though it leaked oil faster then u could pour in it got a 150k motor and trans put in

Re: donor motor questions
 

oil pump is another 60 bucks from rockauto. so far my total is 370 before shipping and taxes lol. wasnt planning on this at all :(

Re: donor motor questions
 

revisiting this! i sold my donor truck and drivetrain...it ended up having water in the oil...guessing blown head gasket. but i did pick up another truck. this one is a 2002 tahoe...dash says 211k. just rolled it in over the weekend and will be tearing it down this week. this one looks very well kept up with..the inside of this truck is immaculant. an older gentleman owned this one.

but anywho, im kind of in the same boat again! my parts list added up quickly..

Valve cover gaskets and grommets
Intake gasket
valley cover gasket
knock sensors and harness
Rear main seal
Rear cover gasket
Oil galley barbel
Timing chain
Front cover gasket and seal
Oil pump
water pump and gaskets
thermostat
spark plugs and wire set

Total from rockauto is 485 shipped (oreilley was about 740). this engine doesnt have near the grime the other one does. but i have to pull the intake to get my engine puller plate on. rear main is a given imo since its hard to get to in the truck. but the front stuff is what im not sure about. none of the front needs to come off unless i just want to change stuff out. already have headers and new oil pan so those are getting new gaskets as well.

i think i know the response on this....but what your opinions? im dead set on the rear seals, but is everything up front really needed to change?

Re: donor motor questions
 

This is what I would do, but it's only my personal opinion.

Valve cover gaskets and grommets If they're not leaking, leave them alone
Intake gasket Yes, especially if you're pulling the intake
valley cover gasket No
knock sensors and harness Only if they look bad or if the wiring looks bad
Rear main seal You're doing this anyway
Rear cover gasket Only if it's leaking
Oil galley barbel If the truck has good oil pressure, no
Timing chain This one's a crap shoot, ask yourself, honestly, how many miles do you think you will put on the truck when done? If just a cruiser for the weekend, then I wouldn't worry about it
Front cover gasket and seal If it's not leaking, then no, but do if you change the chain.
Oil pump If it has good oil pressure, then my response is the same as the chain.
water pump and gaskets Gaskets if you remove the pump for any reason. But if it isn't leaking, no. Odds are it isn't the original pump anyway, and they are easy to change later if need be.
thermostat Same as water pump
spark plugs and wire set Look at them and see their condition. Again, odds are they aren't original either, and are easy to change later too.

Re: donor motor questions
 

good points. I will know a little more when I get it out. someone has already changed the intake gasket, and I'm guessing knock sensors since there is a bead of RTV around to deflect the water. valve covers were only mentioned because I might paint them. spark plugs and wires were really just for tune up purposes. rear main...well that's obvious. sure as hell don't want to change that later down the road.

this truck will not be a daily, just a cruiser every now and then

Re: donor motor questions
 

I would replace the crank sensor only because its really a pain to get at once you bolt on the starter and right hand exhaust manifold.

Re: donor motor questions
 

My donor has 220000 on it and I thought the same as you Kev I resealed it and wanted to replace the oil pump and chain as it is very easy on the stand but I can tell you cost me a little more because then I figured might as well do a cam swap so a heads up it could wind up costing more then you figured. But I am happy I did

Re: donor motor questions
 

lol that's my fear. but I'm just ready to get this truck done. snowballing and dis interest has kept it from being finished a loooong time ago. right now I'm leaning towards the top stuff and of course the rear stuff. think I'm leaving the front components alone. hope to have it pulled tomorrow