Alright boys.  I need a little help thinking this through. I just picked up an 04 Chevy K1500.  The truck has been sitting 4-5 years.  According to the last owner who I know well and trust 100%, it was started a few times a year, driven almost none and was parked because of an overheating issue. The oil is dark but looks good (no chocolate milk here!) and doesn’t seem to have a drop of water in it.  So I am guessing it wasn’t parked with a busted head gasket or cracked head.  The truck starts fine, goes into gear and moves, but I don’t wanna push it.  The gauge cluster is out, except the engine light is on.  It is throwing the standard P0300 multiple cylinder misfire code like any of the newer stuff that sits tends to do.  Got some smoke on startup, but I can’t tell if it’s white or blue.

Please help me make a to-do list to get this girl brought back to life.  I just want to make sure I am doing a few things to start bringing her back easy.  Don’t want to jolt her awake.

Here is what I am thinking so far:

1) Change the oil.  For old cars in similar situations, I have always used 5W-40 diesel oil on account of the souped up dinosaur bones the put in the stuff
2) Run through the air intake and make sure Fievel and Papa aren’t home and their house doesn’t go into the manifold.  Prolly change the filter there too
3) Inspect the belts, replace if necessary
4) Brakes...something is locked up in the rear, causing the truck to hesitate when it moves...gonna have to look at the calipers and fluid.  Prolly flush the fluid
5) Check the ATF and rear differential lube levels
6) Inspect the plugs and replace...prolly
7) I haven’t seen any signs of mice chewing on wires, but I’ll look at the plug wires and the coil harness
8) I dumped the tank and gave her 10 gallons of ethanol free rec 90 and some Seafoam.  I’ll prolly clear the line too, but I haven’t done it yet.

What else am I missing?

here's a tip on overheating for no apparent reason...................

i had a similar issue on a '98 Chevy truck and finally in desperation removed the water pump.......found the damned impeller had come loose from the shaft!!
It was not pumping any water.

If the oil looks ok
I'd worry about figuring out the cooling system before wasting new oil.

Look at the hoses to/from the radiator . They could be soft and if so they tend to suck flat and not pass much water. also check the thermostat-remove the thing to test.


Which engine and how many miles?

Ive seen that on a ford truck. Owner did no maintenance. Never changed anti freeze. Pump impeller rusted the blade off. Had overheating issues and poor heat.
Whole cooling system was garbage.

Considering it is a random misfire codes, leaking no coolant, it could be a head gasket or a cracked block. Top it off with water and run it for a while and see where it is leaking. That sounds like the first thing that should be done.

How many miles? I may have missed that but didnt see it in your post.

Hoses could certainly stand to be changed, but they aren’t to the flattening out stage of life yet.

5.3 and 186k

I will borrow a pressure tester for the cooling system to test for leaks.  The fan clutch is good, so I can throw a thermostat at it while I’m farting around with the system.

Check the brake lines, that gen was common for them to rust thru. Happened to my wife and kids at a red light one day, blew right thru it.

Had to replace them complete, from master cylinder to wheels. Checked my truck and it was same condition, so I got to do it twice

Update:  pressure tested the system and it held 15psi (15psi cap) for over 10 minutes.  I don’t doubt my friend at all that it was overheating.  I guess I will pull the valve covers to see if I can find evidence of a cracked head in the oil drains as these motors are prone to have.  I still would’ve thought there would’ve been milky oil.  But if it was a slow enough leak, I guess not.