Radiator air lock

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00pathySE
Posts: 155
Joined: Wed Aug 12, 2009 6:02 pm
Location: Ontario

Radiator air lock

Postby 00pathySE » Sun May 02, 2021 7:40 pm

Hello all, been awhile since my last post.

I recently drained and filled my radiator and am having trouble filling the radiator fully. My overflow is three quarters full but there is room at the top of the radiator. If I try to draw fluid out of overflow to put into the radiator it seems to drain right back into the overflow and never fill the top of the radiator (it is not flowing through the overflow at the top of the rad). Is there any trick to get the air out of top of the radiator? Thanks.


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palmerwmd
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Re: Radiator air lock

Postby palmerwmd » Tue May 04, 2021 5:42 pm

Our resident expert I am sure will answer you soon :)

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smj999smj
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Re: Radiator air lock

Postby smj999smj » Tue May 04, 2021 11:31 pm

Make sure you don't have the reservoir cap, which is the pressure cap in the system, mixed with the radiator cap, which will NOT have a plunger nor spring on the bottom of it. Top off the radiator and install the cap. Fill the coolant level in the reservoir to the "MAX" line on the side of it. Jack the front of the vehicle up as high as you safely can...or, drive the front wheels on a set of ramps or park on a steep hill (nose forward). Start the engine and set the front and, if applies, rear heater to the hottest temperature setting. Run the engine at 2500-3000 RPM for at least 10-minutes, or longer as necessary until hot (approx. 140 degrees F.) air comes out of the heater vents. When done, shut the engine off and lower the vehicle. Any air should be purged from the system. When the engine is cold, top off the radiator and reservoir as necessary.

00pathySE
Posts: 155
Joined: Wed Aug 12, 2009 6:02 pm
Location: Ontario

Re: Radiator air lock

Postby 00pathySE » Thu May 06, 2021 8:10 pm

Thank you smj once again.

Turns out my aftermarket radiator and cap has a spring and plunger on it. Will this cause an issue? I will follow your write up, thanks again.

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smj999smj
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Re: Radiator air lock

Postby smj999smj » Fri May 07, 2021 6:58 am

Yes, it will, because it impedes the coolant flow to the reservoir. Replace it with the correct cap. If the correct cap won't fit the new radiator, some have addressed the issue by cutting off the spring. The only cap that should have a spring on it is the one on top of the coolant reservoir in this type of coolant system.

00pathySE
Posts: 155
Joined: Wed Aug 12, 2009 6:02 pm
Location: Ontario

Re: Radiator air lock

Postby 00pathySE » Fri May 07, 2021 10:14 am

Awesome hack. I will clip the spring until I find a new one. Thank you!


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