TexRedC4S

I have a 2008 C4S. I installed a new low temp thermostat. Quite a bit of coolant recovered. I am guessing most of the coolant from the engine is what is in my clean bucket. Everything is buttoned up and I need to refill with coolant. I was hoping to start the engine and fill the coolant expansion tank as the engine sucked coolant from the expansion tank. I started the engine and the expansion tank didn’t empty. Nothing happened. I waited about 15 seconds, then shut the engine off worried it would quickly overheat without coolant in the engine / thermostat area.

I guess I am going to have to purchase a vacuum refilling kit? No other way to get coolant into the engine?

i installed a 3rd radiator recently and didn’t need the vacuum kit, was able to refill as the expansion tank emptied into the cooling circuit as I got the system up to operating temp a couple of times. I just kept the expansion tank topped off.

I was hoping I would be able to refill the same way...

ideas?

thx

TexRedC4S

Went back to see if anything changed and found the expansion tank had emptied about half of its volume! Refilled and started it up. Kept the valve open (wire valve on black cap behind the blue filler cap), and kept filling it up. Idled a bit, held revs at 2000 and kept filling. Shut it off. The water temp was at the normal 175. Oil temp had crept up to 120. Still about 1- 2 qts low on coolant...

I think I’ll take it for a short drive and see if it will drain some more from the reservoir. Will watch temp and see how it goes.

TexRedC4S

It worked. Water Temp at 175. Oil temp got to 200. Ambient is 95. AC was on. After the drive can see the expansion tank is only half full! That’s what I was hoping. The 3 front radiators were all at temps above 135.

Now, let it cool and refill the expansion tank. Repeat as needed. I think I got it.

Petza914

Sounds like your close. Much simpler to vacuum fill it as it's a one and done.

TexRedC4S

Petza914, thank you for the suggestion. I am sure I will need to replace my water pump at some point, so I need to get the proper equipment. Do you have a suggested make / model for the vacuum device? I will go ahead and purchase one and get familiar with the operation. It sounded like a complicated procedure when I reviewed the service manual!

thx again.

Petza914

​​​​​​I use the Airlift unit. You can buy it from Amazon.

Pete

Hatzenbach

After I added the 3rd radiator I refilled my coolant with a vacuum tool.
But I still had to add at least 1 quart of coolant after that.
But then again, I'm an idiot and probably had no idea what I was doing

ComradeStan

I used Maddox from Harbor Freight (https://www.harborfreight.com/coolin...kit-64985.html). Worked well but it needs an air compressor to set the vacuum. I also got the compressor from same place (https://www.harborfreight.com/2-gall...sor-64596.html). Just FYI.