Coolant/Thermostat Changeout

[03Explo20]

Just finished flushing my cooling system. I changed the t-stat, hoses, refilled, then started the truck to let it heat so the t-stat would open and purge any air that may be present.

I had the heat on high (idling) and the gauge would rise to the normal range but it would not throw any heat. I decided to take a small drive around the hood to see if that helped it heat and it sure did!

The temp reading in the truck went all the way up to high just 100 feet down the road, the check engine light came on, then the t-stat must have opened as the temp gauge went right back down into the normal position and the truck started throwing great heat!

I used a Motorad Fail Safe T-stat in the truck.

I'm thinking maybe a big air pocket possibly caused this and when it relieved itself everything went back to normal?

I did the distilled water multiple flush routine then filled the degas bottle with two and a half gallons of straight Zerex G05 AF. How long should I want until it would be mixed thoroughly with the water so I can check the freezing rate?

One additional thing, I put the new t-stat in the same direction as the one I removed. Does it matter the position it would be in? This Fail Safe had this little brass "valve" on it that I put facing towards the engine. I don't think this matters but want to be sure anyway!

 

[Number4]

The burp valve position doesn't matter in either the 4.0 or 4.6 due to its orientation. Which engine do you have?

 

[03Explo20]

I have the 4.0 engine.

 

[Number4]

Did you fill the thermostat housing completely before running it? When I replaced my housing, it took for ever to top that off.

If you didn't, then the sensor and the T-Stat would not have been submerged in coolant and only have been reading temp from air. Which means it would take a lot longer to get the tstat to open and could cause the engine to over heat. As fluid wouldn't be flowing.

There are coolant refill tools, cheap ones ranging from 50-100. They rely on an air compressor, but will evacuate and refill a system. I've yet to buy one, but should as I've worked on the cooling system of all my cars enough to warrant it.

 

[03Explo20]

I didn't specifically fill that area, no. I put the AF directly into the bottle after the distilled water flush then started the truck with the heater on full and let it warm up. When it still wasn't throwing any heat, I went for a short drive and that's when the t-stat must have opened and the heater started blowing hot air.

I'm going to go check things out again this morning to see if the AF level has dropped and if any leaks sprung up. I'll start it again and let it idle to see if it heats up at idle.

Thanks!

 

[03Explo20]

Guys, curious if anyone knows for sure. How much water does the block hold? After I did the distilled water flush a few times, I simply added straight coolant to the degas bottle until the system was full. I think it took two and a half gallons.

Would I be close to a 50/50 or 60/40 mix?