I apologize if I missed information for this question during my search.

I replaced the thermostat in my 2007 Saturn Aura XE (3.5L) yesterday. When I tried refilling the system, following the exact instructions in the service manual, none of what I poured into the reservoir flowed down into the block. Finally, I decided to pour coolant into the top radiator hose until I couldn't put any more in. As soon as I removed the upper hose, all of the coolant flowed out of the reservoir into the block.

Any idea why the air is not burping out and is creating an air pocket when I fill the system? I know that there is a specific line to allow the air in the block to return to the reservoir, but mine doesn't seem to be operating correctly.

IDEAS?

 

Here is the factory procedure, I usually open a top hose and let the air escape like you did when you removed the top hose.

 

That's exactly what I tried to do. Any idea why that doesn't work and why we have to remove the hose?

 

No idea why the factory recommended procedure does not work on your car. That is also why as a professional mechanic I take a hose off to let the air out.

 

I remember seeing an illustration somewhere of all of the pipes/parts in the cooling system, but I can't locate it now. I think that one of the metal pipes had something to do with allowing the air in the system to make its way back to the reservoir. Could it be that this pipe is somehow blocked?

Also, can the system be bled by running the engine with the surge tank cap not being in place? Like when those large fill funnels are used?

 

You may consider vacuum filling the cooling system. I have an Audi A3. I naively tried to fill it the normal way. What I found out the hard and messy way is that when the configurations get complicated, and the engineers don't mind you doing a little extra work to get all the air out, they develop systems that simply can't be properly blended by the old standard methods. Pulling a vacuum on the cooling system not only checks for leaks but also leads to as little air in the system as possible. You'll never get it all but it is pretty damn close. The equipment to do so is not terribly expensive. The hardest part is probably finding a vacuum cap that fits your reservoir

 

I bought one of those to use on my old Dodge Intrepid. I had seen a video on YouTube of someone using one and really liked it. I pulled a vacuum and it held without leaking (I liked the way it collapsed the hoses). But, for some reason, it wouldn't pull in the coolant in. So I returned it. I've been toying with the idea of trying again with a different one, but I keep debating whether or not I will use it often enough to justify the price. Some day???

Thanks, everyone for replying.

 

I purchased a vacuum filler years ago when I had my retail repair shop. I used it a few times until I destroyed a radiator on a Jeep pickup. The top tank collapsed and I purchased my customer a new radiator. It has been in a drawer ever since. For the last 20+ years before I retired my guys have used one at the power company with great success. The newer rigs are designed to be vacuum filled.