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Discussion Starter · #1 ·
89 12 valve. Had to replace the radiator, drained about 2 gallons out of the radiator, I put two gallons in, squeezed the upper rad hose and all the bubbles seemed to escape. Well I was reading a bunch of forums saying “put the funnel in and let it suck it down and fill it more as it gets low.” Well in attempting this, the coolant actually just raised, never went back down. This is after about 3 minutes of idling. Did I do anything wrong? Is this normal? Is the system bled of all the air now?
 

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Jack the front of the truck up a little and wait about a 1/2 hour then take the pipe plug out at the front of the cyl head and the air will bleed out. I put a radiator petcock there so that it's easier to do it and not waist alot of coolant.
 
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To actually burp the coolant fully you need to have it get warm enough to open the thermostat. Not sure about your truck, but mine takes way more than 3 minutes of idling to get that warm. You'll want to get it warm enough that the top rad hose starts having heat flow through it.

Are you having overheating issues? What makes you think that you have trapped air?

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Jack the front of the truck up a little and wait about a 1/2 hour then take the pipe plug out at the front of the cyl head and the air will bleed out. I put a radiator petcock there so that it's easier to do it and not waist alot of coolant.
Good idea on the petcock. For me, I pulled that plug, filled until it poured out, then put the plug back and topped off the rad and reservoir. Worked fine for me.

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Good idea on the petcock. For me, I pulled that plug, filled until it poured out, then put the plug back and topped off the rad and reservoir. Worked fine for me.

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It also doesn't need to be warm actually it's better to do it after it has sat for a while because it gives the air time to gather in one spot. I just crack it open and as soon as the bubbles quit close it, sometimes when I check my oil i'll crack it open just to see if any come out.
 

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Discussion Starter · #6 ·
It also doesn't need to be warm actually it's better to do it after it has sat for a while because it gives the air time to gather in one spot. I just crack it open and as soon as the bubbles quit close it, sometimes when I check my oil i'll crack it open just to see if any come out.
I’m waiting for the rad fluid to go down now. It’s parked on a slight inclined. I don’t think it’s overheating, but the radiator was leaking bad so I. Replaced it. I have to drive it 3 hours today and don’t want any overheating issues. I tried to crack that 3/8 square bolt and it’s not budging. Any ideas?
 

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Are you using a breaker bar on the plug?
 

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That's after the t-stat and wouldn't be much different then trying to get the air out through the radiator cap. I guess you could try it if you still can't get the plug out.

Do you have any crayons or candles, if so then heat the plug up a little and then put them on the threads of the plug. It will usually help the plug come out better.
 

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Discussion Starter · #11 ·
That's after the t-stat and wouldn't be much different then trying to get the air out through the radiator cap. I guess you could try it if you still can't get the plug out.

Do you have any crayons or candles, if so then heat the plug up a little and then put them on the threads of the plug. It will usually help the plug come out better.
Good thinking! If I get it off I will. I’m going on a test drive now to see if the temperature stabilizes normally. The sensor that I showed is hooked up to a trans temp gauge and that goes all the way to 300. What can I expect a normal operating temp for just cruising around? 210?
 

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Both of my 12v's run 180 to 190 and that's with using electric cooling fans. They very seldom come on either.

Could be that your fan clutch is bad.
 

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Discussion Starter · #13 ·
Oh sorry, its not reading 300 when I’m driving. That’s just what the gauge is capable of reading. I’ll check the gauges in about 30 min when I go for a drive
 

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Discussion Starter · #14 ·
Well ran the truck a mile down the road and barely made it back before pegging the gauge
 

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Sounds like coolant isn't moving. Have you replaced or checked the thermostat or water pump yet?

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Are you sure your gauge is good?
 

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Discussion Starter · #17 ·
Are you sure your gauge is good?
Oh I’m sure. I got home and opened the hood. I could see I tiny bit of steam from wd40 and it felt hot under the hood. Do I have to wait until it cools down to open the 3/8 bleed screw.
 

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Discussion Starter · #18 ·
I’m
Sounds like coolant isn't moving. Have you replaced or checked the thermostat or water pump yet?

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hoping it’s just a huge air pocket. I barely got 2 gallons of coolant in. Plus before all this it ran just fine without overheating
 

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Oh I’m sure. I got home and opened the hood. I could see I tiny bit of steam from wd40 and it felt hot under the hood. Do I have to wait until it cools down to open the 3/8 bleed screw.
If you don't want a hot coolant bath you need to wait for a while just jack the front of the truck up a little while your waiting for it to cool.
 

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Discussion Starter · #20 ·
If you don't want a hot coolant bath you need to wait for a while just jack the front of the truck up a little while your waiting for it to cool.
Well dang. I was supposed to leave in half hour… oh boy lol… so when I first filled the new radiator it took about 1.8 gallons after squeezing the upper rad hose and filling the coolant tank. Now 2 gallons isn’t a lot… when I started it and let it run, the coolant was rising into the spill proof funnel. Could that have been a big air bubble coming up?
 
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