Oil and overheating
 

Hi guys :) Welps my 65 GMC 1000 V6 was running so fine and then ...
(stop me if you've heard this) it started using oil which it had not done much before.
Then I noticed the original bronze radiator had started leaking. Tried to fix it but also ordered a cheap chinese alluminium radiator, until I can braze better.

I ended up putting in the aluminium with a better metal drain plug with zinc anode. Thought all was good but then it lost water from possibly a leaky bottom hose clamp and over heated badly. Barely made it home.
Put a new clamp on and fresh antifreeze and checked for leaks seems to be good.
And now I have to figure out whats going on.

maybe thermostat or waterpump? But the oil use worries me too.

First question: Should I use 30W or regular 10-30 for my 302V6?
AND should it be detergent or non-detergent?
Thanks Roger

Re: Oil and overheating
 

Before we figure out what oil to use lets figure out where the oil is going. Where do you think the oil is going? Is the motor smoking out the exhaust - leaking puddles on the ground - leaking oil in the radiator? My first thought about your problem was - did it all start at once? This can't be your first experience of having engine problems - tell us more.

Re: Oil and overheating
 

Yeah that oil didn't just get swiped by mice or something. Are you seeing any oil in the water or vice versa? The reason you have no water is because of the bottom clamp so that's not a mystery. Fill it up again and watch the level. You can probably have the original repaired at any radiator shop for about $100

The oil though, that's trouble. No slick = no run.

Re: Oil and overheating
 

Fill up your radiator - start the truck and look in the radiator and see if you have any bubbles or oil film - if you do you will know where your oil is going and why your radiator suddenly is leaking along with the oil loss. If I remember correctly you stated the truck hadn't run for 5 years - if it wasn't put "to bed" correctly you may have a leaking head gasket - which in turn will cause overheating. Overheating causes bigger problems.

Re: Oil and overheating
 

I need oil NOW!
Should I use 30W or regular 10-30 for my 305V6?
AND should it be detergent or non-detergent?
Thanks Roger

No oil in the radiator system. Not even sure she's using much.
Not overheating now, was a slow leak bottom hose clamp replaced.
And won't know if she's still using oil until I get out and I can't do that because I'm down to 1 quart so...PLEASE answer my question.

Re: Oil and overheating
 

Here's the oil recommendation thread I made a while ago. I still use Shell Rotella 15w40 in Cecilia. She needs the zinc for those flat tappets.
https://6066gmcclub.com/showthread.php?t=47432

A quote that has all the goodies:
Shell Rotella has 1400 PPM of Zinc, Valvoline Racing Oil is 1700 PPM, and Chevron Delo all meet the minimum for use with Flat Tappet Cams, and are a cheap alternative for breaking in a motor.