Over heating due to air pockets

Best Deals · November 12, 2021

Trucks overheating. The needle stays right in the middle at first but then slowly goes up.

I opened the coolant reservoir and hit the accelerator until it started bubbling (pretty hard I might ad) attempting to burp the system. But it seemed to make things worst doing that because now it does not cooldown when before I did that it would heat up a little then cooldown (when the thermostat would open I assumed)

So far I replaced the thermostat and the water pump(broke the thermostat bolt in the water pump doh!) I also bypassed the heater core to rule it out.

Both top and bottom radiator hoses where very hot.

My gf thinks its the headgasket but they where fine before I messed with the coolant.

What should I do I'm about to have it towed to the stealership I'm thinking it needs to have the air bled out. Anyone know what the proper procedure is to purge the air from coolant? Its a 4.8 1500 Silverado 08

Also any point in the right direction would be greatly appreciated on what to do or what you think it is.

Edited November 12, 2021 by Best Deals

Sharpz · November 12, 2021

Your girlfriend might actually be right. When exaust gases bypass the head gasket they super heat the fluid as I am sure you know. You dont want to rev the engine to bleed the system. Things I have found that help remove air is to have the truck on a bit of an uphill angle either by jacking or ramp, with the front being higher. I have also found that squeezing the top hose pushing coolant toward the pump also aides. Also make sure your radiator is clean, and that your fan clutch is working. Steps for removing air pockets.

1) inspect all hoses making sure they are good condition.

2) if empty system or mostly empty system due to water pump replacement, fill the overflow about 1/3 higher then recommended fill cold line. Dont worry this will still not be enough.

3) with the overflow top off, start your truck and let the truck idle until it gets up to temperature. If the coolant starts coming out the reservoir top, turn the truck off, wait for a few minutes and try the procedure again.

4) continuing monitoring the temperature gauge and the coolant level making sure it never goes empty. Try to keep it at the fill line.

Do not be afraid to stop and start this procedure. If after the truck gets up to normal temperature and you dont see any more bubbles, you can put the reservoir top back on. You should be good to go from here, if your truck doesnt climb in temp, take it for a short test drive, if your temperature climbs again, you may try the procedure again, if that doesnt work you will want to get that head gasket looked at.

Best Deals · November 12, 2021

3 hours ago, Sharpz said:

Your girlfriend might actually be right. When exaust gases bypass the head gasket they super heat the fluid as I am sure you know. You dont want to rev the engine to bleed the system. Things I have found that help remove air is to have the truck on a bit of an uphill angle either by jacking or ramp, with the front being higher. I have also found that squeezing the top hose pushing coolant toward the pump also aides. Also make sure your radiator is clean, and that your fan clutch is working. Steps for removing air pockets.

1) inspect all hoses making sure they are good condition.

2) if empty system or mostly empty system due to water pump replacement, fill the overflow about 1/3 higher then recommended fill cold line. Dont worry this will still not be enough.

3) with the overflow top off, start your truck and let the truck idle until it gets up to temperature. If the coolant starts coming out the reservoir top, turn the truck off, wait for a few minutes and try the procedure again.

4) continuing monitoring the temperature gauge and the coolant level making sure it never goes empty. Try to keep it at the fill line.

Do not be afraid to stop and start this procedure. If after the truck gets up to normal temperature and you dont see any more bubbles, you can put the reservoir top back on. You should be good to go from here, if your truck doesnt climb in temp, take it for a short test drive, if your temperature climbs again, you may try the procedure again, if that doesnt work you will want to get that head gasket looked at.

Thank you for your response. I tried this morning your procedure.

After it heats up and the needle passes the middle it overheats and the coolant spills out the reservoir so i turn off the truck gonna try again later when the coolant level drops.

Is this normal? Sounds like the head gasket eh? Any chance its not? It seems pretty pricey to change them.

PS no milky substance in oil stick seems like oil

Edited November 12, 2021 by Best Deals

Sharpz · November 12, 2021

10 hours ago, Best Deals said:

Thank you for your response. I tried this morning your procedure.

After it heats up and the needle passes the middle it overheats and the coolant spills out the reservoir so i turn off the truck gonna try again later when the coolant level drops.

Is this normal? Sounds like the head gasket eh? Any chance its not? It seems pretty pricey to change them.

PS no milky substance in oil stick seems like oil

yeah there is a chance that nothing is wrong with the head gasket. You can try shutting the truck off before it gets up to temp. Do this after a decent cool down period. Are you observing bubbles in the overflow tank? If you want to see if the head gasket is leaking gases into your coolant just inspect your plugs, if coolant is getting into the cylinder the plug will look super clean, almost bleached free of oil.