Radiator, Thermostat, Water Pump Issue (78 C10/Big 10 w/Vortec 5.3)

[mbkairborne]

I have no coolant flow.

While at a drive thru, my truck started to overheat...Upon parking, I noticed a plastic T broke where the heatercore hoses (I belive) run together and had leaked out quite a bit of coolant out. Secure new t at auto zone across the street, added coolant and off I went...got about 1/2 a mile and strted to lose power, i noticed temp gauge rising quickly. I pulled off tthe road and towed her home.

After a diagnosis of radiator hose lines under idle, I noticed top and bottom hose was not warm and had no pressure. I bought a new thermostat and installed it, refilled radiator and started it up....after 15-20 minutes, neither the bottom or top hose came under pressure...only a very slight movement of water at radiator neck. There seems to be no flow from radiator bottom hose through water pump and no flow out of top end through top hose back into radiator. At idle, the temp never went above halfway mark...I drove truck a quarter mile down the street and temp satrted rising to 3/4 mark and by the time i got back to the house it was almost pegged out and engine had very little power.

A friend of mine helped me check play on fan and belts and look for leaks around water pump...it seems ok...no noises when running.

We also checked oil diptick for any signs of coolant that might indicate other issues and oil is fine.

I did have the truck serviced the day before including oil change, rotate balance and front end lube.

Short of changing the waterpump just cause, we are stumped.

Thoughts?

 

[Goldie Driver]

Clogged radiator, perhaps?
Or, bad water pump.

My .02.

Best of luck!

 

[fast 99]

Most overheating problems have multiple issues unless just out of coolant. Really sounds like it is air locked after dumping coolant. Bleed air out either by temporarily disconnecting a heater hose at top of intake or remove thermostat housing & stat. Fill up to the stat and re-install. Don't buy a economy stat they are junk.

 

[Hunter79764]

Make sure your air is out, going from warm to overtemp that quick sounds like air pockets to me. On the 5.3, do you have the crossover tube/steam vent line? Disconnect that, and fill the upper radiator hose until it comes out the steam line. Then reconnect the upper hose and top off the surge tank and/or overflow tank.
x2 on good thermostats, I've had aftermarket ones fail/open erratically, but haven't had an issue on an OEM one, even out to 200k+ miles. Not saying your old one didn't fail, but the new one might not be fixing problems like you would hope.

 

[fast 99]

Make sure your air is out, going from warm to overtemp that quick sounds like air pockets to me. On the 5.3, do you have the crossover tube/steam vent line? Disconnect that, and fill the upper radiator hose until it comes out the steam line. Then reconnect the upper hose and top off the surge tank and/or overflow tank.
x2 on good thermostats, I've had aftermarket ones fail/open erratically, but haven't had an issue on an OEM one, even out to 200k+ miles. Not saying your old one didn't fail, but the new one might not be fixing problems like you would hope.

Your bleed procedure is correct ignore mine. One I posted was for a small block. 5.3 of course is different.