350 Won't Stop Overheating

[5Tractorguy]

Originally Posted by cadillac_al

How hot is hot? boiling over? That is weird that the radiator is cool on one side.

Got hot enough to boil for a brief minute in the top hose once... I didn't run it as long thereafter so nothing would be damaged.

Originally Posted by hotsam

This may sound crazy but is your timing advancing correctly when the advance is hooked to vacuum? The radiator temp difference does seem strange though..

Originally Posted by hotsam

Also it's not sucking a hose flat when thermostat is in and cap on ??

Believe so, though I will double check tomorrow. It's currently set to 8deg, when I plugged the vacuum advance line back in there was a significant difference, but the mark stayed at 8 last I remember checking...

Negatory on the flat hose, maintains form.


So, I seemed to have licked it. Was a bad (brand new) thermostat of all things. Pulled it out of the truck and put it and another new thermo in a pot of water. (Both are 180's). The new one opened at 180+/-, the other from the truck didn't until the water began to boil heavily.

That's makes 4 brand new thermostats I went though this week until I got one that worked.

[kwmech]

What year is this and do you have a serpentine belt system or V belt. I'm thinking wrong water pump

[5Tractorguy]

Originally Posted by kwmech

What year is this and do you have a serpentine belt system or V belt. I'm thinking wrong water pump

It's an '88, still the square body style. Has a serpentine belt but not the setup like the GMT400's. Still turns in the same clockwise direction as the V-belt setups.

[Getter-Done]

Originally Posted by 5Tractorguy

So, I seemed to have licked it. Was a bad (brand new) thermostat of all things. Pulled it out of the truck and put it and another new thermo in a pot of water. (Both are 180's). The new one opened at 180+/-, the other from the truck didn't until the water began to boil heavily.

That's makes 4 brand new thermostats I went though this week until I got one that worked.

Glad you finally got a good (New) part.

Stuff like that just adds to the issue.

[5Tractorguy]

Originally Posted by Axle

I'd be very suspect of the water pump having the wrong impeller in it. Even with the wrong impeller it'll still look like its moving coolant, its just not able to move enough volume.

Same thought crossed my mind too... I originally put a new high volume pump on figuring it would only help. Ended up ordering a stock volume pump and changing it out thinking the high volume was too much or wrong impeller.

Originally Posted by Getter-Done

Glad you finally got a good (New) part.

Stuff like that just adds to the issue.

Thanks, me too!


One last thing... anyone have recommendations for a rebuilt engine break-in procedure? I went for a short 3 mile drive today. Planning on changing the oil before I go on a longer drive tomorrow afternoon.

General consensus online seems to be don't do anything but regular driving, no hauling for the first 500 miles. Maybe 1-2 more oil changes before then.

What do you guys think?

[Getter-Done]

After you (Think) the Cam is broke in

You can Drive it like you stole It.

Just vary RPM a whole lot.
Don't hold it at at certain RPM.

I would keep RPM's under 4 grand for a while

That's if you can keep your foot out of it.