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Radiator not pulling in coolant!

I have a 2006 Chevy Uplander. I just replaced the thermostat and water pump. And I’m trying to fill the radiator got 50/50 and it’s not taking the fluid. It’s just spilling out the top. I have the car running and bleeder valve open. Tried adding coolant through the resivior. Still not taking fluid. I’m stumped!

Try squeezing the upper/lower radiator hoses - it will “burp” the system eventually.
Also, check what repair manual on your car tells, it may require to vacuum the system and then fill it from the top, it is a special tool for that.

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Dexcool sludge my guess.

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Good ideas above. Be sure to turn the heater to max also, so the heater core is in the loop too.

It’s possible however that what you are trying to do can’t be done. The spec for example says your car holds 4 quarts. But it overflows after 3 quarts. This is b/c there’s one quart of the old coolant still in the engine.

What I’d do in that situation is fill and drain the system with plain water several times, idling the engine a few minutes each time in between. That should get most of the old coolant out. Now refill the system by first pouring in 2 quarts of full-strength 100% coolant. Then top it off with plain water. You’ll end up with a 50/50 mix. You need to make sure the coolant mixes with the water of course, otherwise the places where there is only water might freeze, so be sure to drive the car for 30-60 minutes or so with the heater on max. That usually mixes everything pretty good.

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We have several Uplanders in our fleet . . .

the most effective way to do this particular vehicle out is to drain it completely, draw a vacuum and then fill the system, as @thegreendrag0n already stated

otherwise, you’ll more than likely be battling air pockets, lack of heat and all sorts of other nastiness

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I’ve already done that and completely flushed it and drained everything. The manual didn’t state anything about a vacuum. I did a chemical flush prior to the pump and thermostat.

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I’m not sure which manual you’re talking about . . . owner manual?

As for our fleet’s Uplanders . . . the general motors factory service manual and technical information website does mention using the vacuum method for servicing the cooling system

Ok I was looking at an owner manual but I’ve also watched several videos online. How many gallons does my type of radiator usually take? I’ve read in several places it’s about 12 qts. Maybe I’ve missed something and it’s only about a gallon idk

Which engine, 3.5 or 3.9L?

It is a 3.5l

The cooling system approximate capacity is 11.3 qts. with front HVAC only, regardless of engine size. If the vehicle also has the rear HVAC unit, the capacity is about 12.8 qts.

The service manual gives both static and vacuum fill procedures. The vacuum method is not required, though it may work better. The engine should not be running when filling.

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Air is likely trapped and loosening the highest heater hose connection and with the hose disconnected pour coolant in the radiator and when full replace the cap, install the heater hose but leave the clamp loose and start the engine. As soon as coolant leaks at the hose connection tighten the clamp. If no coolant leaks there twist the rubber hose while the engine is running to give the air a better chance to escape.

You know this ain’t rocket science… And if the thermostat had a weep hole drilled in the base ring this would be so much quicker to accomplish.


Thanks will get back to you on this. Gotta wait for daylight. This sounds like a great idea

You have received good information from the folks thus far. Keep in mind “burping” the cooling system can sometimes take a couple days to purge all the air out of the system…without using specialized tools that are geared toward helping this process along.

You mentioned a bleed valve… this is good… when filling the system, be sure the cabin temp is set to its highest (warmest) so that the heater core or CORES are included in the system fill and burp (some vehicles have more than one heater core with these new confounded front and rear climate control systems in vehicles these days). Then fill the system as much as you possibly can and get the engine up to operating temp… see if you are able to add more coolant as the engine warms up… Get as much as you can in the system and then put the rad or reservoir cap on tightly… After that you must allow the engine to cool completely…and I mean completely… This can take many many hours for the system to get truly cold (cold as if you haven’t run the engine that day and or like on a cold morning without having run the engine prior) More than 3 hours easily… so keep this in mind there is no way to rush this process without special tools and equipment.

These Hot and Cold cycles are what does most of the heavy lifting when trying to purge air from a cooling system…and it take a long time to perform just one Hot Cold cycle as the system holds heat in for many hours as I’ve mentioned prior.

I would say that it can take about 2-3 TRUE Hot and Cold cycles to fully purge the system. So…try to do the last fill up in the evening… getting as much coolant in as possible…put the cap on… run engine until hot… and then let her sit overnight… next day…check level… add as much as you can…install cap tightly…run engine till hot… and then shut it down and let it cool for at least 4 hours… Rinse and Repeat till all air is out…

Should take no more than 3 real Hot and Cold cycles… if it does seem to need more attention after the 3rd cycle… you may indeed have another problem that needs addressing such as a leak in the system somewhere…you cannot have any kind of breach in the system anywhere as this will foil all the efforts to burp the system.


I guess this van is just going to take a few days to get it full of radiator fluid it just wont take much fluids. It started to once the can started getting hot but my uncle had the radiator cap on so we couldn’t put more in so now letting it cool

Oh my… I cannot believe i left this one detail out in that book I wrote above. When you are doing those hot and cold cycles… be sure that not only do you have the rad as full as you can get it… Make sure that the overflow container is topped off as well. When the system is cooling down…this is where it will pull the new coolant from to replace any air that was pushed up and out during the fluids expansion when hot… when the coolant cools and shrinks in mass…this will create a suction force…and it will suck up new coolant from the bottom of the overflow…to replace any air pocket that had been purged…

So it is vital to keep that overflow up to the full line during that procedure. I apologize for leaving that detail out… that was very silly, I shouldn’t have assumed that you knew to do this… perhaps you did know… but I didn’t include it so… my apologies. (I will bet you knew however)