Changing Anti Freeze

[Mike Wenrich]

I'm just completing a plenum rebuild and heater core replacement on my 2004. Drained all the coolant (4 gallons) to do this work and today after refilling just two gallons the radiator splashed over. Figured I needed to start the engine to warm the thermostat up enough to open and ran the engine for over 30 minutes before getting nervous and shutting down. Took a long time to get up to just below 200 degrees and the stat never opened. The housing was warm and the heater hoses but the radiator and upper hose remained cool.

It was 54 degrees out and the fan was turning the whole time which probably increased the warm up time but is it possible an air lock is preventing the thermostat from opening? Darkness overtook me so I had to shut down anyway but it was taking a looooong time to get up to heat just idling. Looking for suggestions on what might be going on. I should be able to get two more gallons in there.

I have drained and changed anti freeze before but never to this complete degree. Thermostat and water pump are relatively new. Prior to this work all was normal. Any suggestions? I don't want to blow something up out of ignorance.

 

[Darkbloodmon]

If you have ramps roll the front end up to tilt the coolant to the back of the block and fill it that way.

You can also opt to fill from the thermostat housing itself, 3 bolts and its off.

Trying to get the truck up to temp idling in any climate but the deserts will be a struggle, its better to just fill as much coolant as you can, top off the reservoir and drive it till it self bleeds the air pockets out and pulls from the reservoir.

 

[Ozymandias]

If you have a factory thermostat then it has a wiggle pin that let's the air through into the radiator. The Gen3 has no air locks, it bleeds itself completely.

For the warm up time, it takes forever to come up to temperature that way.

Fan turn always as soon as the engine runs, it isn't engaged, just drag that pulls it along.

My way to fill is; fill as much as possible into the radiator, leave cap of, start engine, top of coolant till it starts to overflow while the engine is running, give a couple kicks with the throttle to speed up the water pump, top of again, put radiator cap on and take the truck for a hard 30 minute drive to bring really up to temperature.
Check next morning for level.

 

[AH64ID]

What brand thermostat is in the motor?

Total system volume is just over 7 gallons, so take that into account if you’re adding concentrate.

 

[Mike Wenrich]

Not sure what brand the stat is but there were no issues before the build. If it takes 7 gallons in the system then likely driving it a bit will move the stuff around and not harm the engine. I was thinking with only being able to add two gallons might damage the engine doing that. I do feel some water pressure on the upper hose so fluid is there and just not moving. When I get the brake light situation figured out and working I will drive it around the neighborhood.

 

[AH64ID]

If the head is where the air bubble is then you can damage the head before the thermostat would open from the air temp, since it’s not in a coolant bath.

I would pull the thermostat housing and fill it that way before driving it.

 

[Mike Wenrich]

I took it for a drive today after replacing the brake switch and saw the temp fluctuating so I know coolant got past the stat. I will put more coolant in tomorrow and hope no damage was done. When I fist started the engine I felt heat in the heater core hoses and the one going to the head so I hope fluid got in there. Further to follow. I did think about pulling the stat housing but that was as far as I got with that thought.

 

[Mike Wenrich]

Put two more gallons of coolant in and all is good. Heater/defroster works well so the blend door work is satisfactory. Next will be the refill of freon. Good to have the truck back in service. I missed the simplicity of driving this truck over the new one. Loaded it with trash and recycles yesterday and made the run to the landfill. We do have trash haulers in the area but mostly for businesses. Most people haul their own trash here in the hills. TDR is a great forum for these trucks. Got me through the blend door repair and other issues. Now resting my body before doing the neighbors blend door repair. Think I got this! Thank you ALL!