Tuesday, June 2, 2015

Bleeding the coolant system on a gm 3.1 or 3.4 revised

alright this is a video i have had up for awhile but i didn't cover the expansion tank version , most of the same principles still apply . im going to explain how to bleed this one using the expansion tank . for now here is the radiator cap video (and yes i didnt have a spill free funnel during this film )
this video if following the instructions i give is a full proof way to bleed the system if there are no other restrictions and or issues with the cooling system.
To reiterate the steps i will list them here

 bleed the system by opening the radiator cap (when its cold) and top off coolant, if you have the expansion tank just remove the cap and set it aside but still have easy access to it .
 run the car at a accelerated idle about 1000-1400 rpm as the car heats up the antifreeze level will rise.
Some may spill and overflow a little bit but this is ok. If using the lisle spill free funnel you just need to leave it hooked up to the cap and or expansion tank . and when it gets to operating temperature or close shut the radiator cap if no bubbles. and only if then open the bleed valve(driver side above thermostat) small turn if it continues to run hot to get the stubborn air out. If you have the expansion tank then this bleeder is open to the tank and there is nothing to turn )

 when it runs in the normal range then wait for it ( engine off) to cool down then open the cap (COLD) and top off coolant , if you touch the other bleeder it could blow off so only and I repeat only open that if its below 100 degrees Fahrenheit

 this bleeder can be opened when the first initial fill is happening after a major service.

After these steps close all bleeders and cap and run car normally and check for proper operation

Repeat the process if the car overheats or runs hot

and i stress if any part of the coolant system was opened thermostat, water pump , intake gaskets and so on any hoses removed, anything besides simply opening up the cap you need ABSOLUTELY  need to perform this process 


7 comments:

  1. Awesome video, great instructions, just what I needed to fix my heat loss problem! Thanks!

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  2. Hi - I needed to just add a little coolant to the system so I opened the radiator cap and added it - do I need to bleed the system? From what I understand of the video and your instructions I don't think so, but I want to be sure. :) Thanks very much - very informative website, esp. for those of us who know just enuf to be dangerous. :)

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  3. What do you do when there's a bypass tube going from the thermostat housing over to the expansion tank? Just run run run it until it purges itself?

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  4. What do you do when there's a bypass tube going from the thermostat housing over to the expansion tank? Just run run run it until it purges itself?

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  5. There is no fluid coming out to bleed what's that mean?

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