Has anyone tried vacuum to fill cooling system

[Wageslave]

Just wondering if anyone has tried pulling a vacuum on the cooling system to get it to fill completely?
I'm changing out the upper coolant hose on the engine and was thinking it was worth a try.

Any suggestions?

[iblackwe]

After having many many issues with my cooling system, overheating, airlocks etc. This is the technique I will be using to fill the system. I would also highly recommend exchanging the corrugated tubing for some plain Jane aluminum tubing as the stock subaru water pump operates much better with less resistance.

[Sgt.Gator]

Just wondering if anyone has tried pulling a vacuum on the cooling system to get it to fill completely?
I'm changing out the upper coolant hose on the engine and was thinking it was worth a try.

Any suggestions?

It's been mentioned here before and on other Subaru forums, several of us use the UView 550000 Airlift Cooling System Leak Checker and Airlock Purge Tool Kit, works great. It creates a vacuum then you fill the system.

[Mitch Wright]

I use the Airlift Purge kit, gets the job done in no time.

[Wageslave]

I used the same device by another name and it didn't work for me. I pulled 24 inches of vacuum and held it for several minutes, then switched it over to draw the coolant in until the vacuum was gone. I still got an air pocket and almost overheated the engine. I wound up having to pull the upper rad mounts, lift the rad and burp the air out.

[Wayne Presley]

I just filled another 818 yesterday, filled up the first time with the VCP cooling system mod. And you do need to loop the heater hose for proper thermostat operation. This car had the heater hose and oil coolers lines plugged when it came in. I did a full fill and it would keep heating up and i shut it down at 217°. I put the heater loop back in, refilled the system and now it sits at 187°.

[Wageslave]

I just filled another 818 yesterday, filled up the first time with the VCP cooling system mod. And you do need to loop the heater hose for proper thermostat operation. This car had the heater hose and oil coolers lines plugged when it came in. I did a full fill and it would keep heating up and i shut it down at 217°. I put the heater loop back in, refilled the system and now it sits at 187°.

Wayne,
To qualify things, I bought my 818 from someone partially complete, it's becoming clear that some short cuts were taken in an effort to get the car running and sellable.
That being said I am woefully ignorant about what you said about the heater hose loop, my engine has the VCP mod done and it is tee'd into a line running into the fill tank on top of the engine. Unfortunately the builder failed to put a clamp on a line running into the bottom of the tank which results in a leak at temperature, that's what started my journey on all this. Is there a thread on the Forum that would educate me? My engine ran hot enough that I heard water boiling after I shut it down to cool, hopefully I didn't damage the engine. After cooling I burped it several time until I got it to cool. Even after burping and filling it would heat up when idling until I revved it up and it would cool down relatively quickly.

[Hindsight]

When looking at the engine from the rear of the car, just to the left of the starter there are two metal coolant pipes about 3/4" to 5/8" in diameter. The terminate one on top of the other with their ends facing the rear of the car, again, just to the left of the starter. There should be a U-shaped hose that connects the ends of these two pipes together.

[UnhipPopano]

This indicates that there might not be a vent from the top of the radiator to the burp tank, and answer why the car develops air pockets.

"I wound up having to pull the upper rad mounts, lift the rad and burp the air out."

[Wageslave]

When looking at the engine from the rear of the car, just to the left of the starter there are two metal coolant pipes about 3/4" to 5/8" in diameter. The terminate one on top of the other with their ends facing the rear of the car, again, just to the left of the starter. There should be a U-shaped hose that connects the ends of these two pipes together.

Hindsight,
What I found was a looped hose that runs from a metal tube that comes out over the top of the drivers side head to a metal tube that comes out from under the intake manifold at the center of the engine. Would that be the same as you described? I have a 2 liter turbocharged engine out of a 2003 WRX.
Thanks

[lclevert]

Wageslave, thats the same as my 02 WRX. The heater tubes are much farther apart than some other engines.

Skip

[Mitch Wright]

Yup that is the same as my 04 2.0 EJ 205 tubes about 12" apart.

[Wayne Presley]

EJ205, about 12" apart
EJ255 about 2" apart

[Wageslave]

Yes, found the loop.
Wish it solved my over heating problems. Found one, missing hose clamp on line going into the bottom of the fill tank on the engine. Hard to find only leaked when the engine is hot and was only able to see it leak with the firewall removed.

[STiPWRD]

This indicates that there might not be a vent from the top of the radiator to the burp tank, and answer why the car develops air pockets.
This is not needed, I capped my burp line from the radiator and my 818 runs just fine. I only have a burp line from the degas tank on top of the engine. I also did Wayne's cooling mod and used the air lift tool mentioned above - it worked like a charm.

Wageslave, how many times have you cycled the engine to try and get the air out of the cooling system? It can take a few cycles. If all else fails, I'd recommend that air lift tool.

https://www.amazon.com/UView-550000-Airlift-Cooling-Checker/dp/B0002SRH5G/ref=sr_1_1?ie=UTF8&qid=1443050002&sr=8-1&keywords=airlift

[Wageslave]

This is not needed, I capped my burp line from the radiator and my 818 runs just fine. I only have a burp line from the degas tank on top of the engine. I also did Wayne's cooling mod and used the air lift tool mentioned above - it worked like a charm.

Wageslave, how many times have you cycled the engine to try and get the air out of the cooling system? It can take a few cycles. If all else fails, I'd recommend that air lift tool.

https://www.amazon.com/UView-550000-Airlift-Cooling-Checker/dp/B0002SRH5G/ref=sr_1_1?ie=UTF8&qid=1443050002&sr=8-1&keywords=airlift

I have the burp line running from the rad to the degas tank. Waynes cooling mod was done and I did use the vacuum tool to fill the system. I cycled it several times to get all the air out and by the time I did and the engine warmed up I discovered the hose leak at the bottom of the degas tank. All this trouble over a missing hose clamp. Now I'm wondering what else was left half done. Found the fuel tank vent line wire tied half way up the filler neck with the end open. I'm adding a charcoal canister and moving it to the back of the engine bay.

[Wayne Presley]

I have the burp line running from the rad to the degas tank. Waynes cooling mod was done and I did use the vacuum tool to fill the system. I cycled it several times to get all the air out and by the time I did and the engine warmed up I discovered the hose leak at the bottom of the degas tank. All this trouble over a missing hose clamp. Now I'm wondering what else was left half done. Found the fuel tank vent line wire tied half way up the filler neck with the end open. I'm adding a charcoal canister and moving it to the back of the engine bay.

The motors idle a little warmer (6-9°F), hold 1500 rpm and they cool off to the thermostat temp. I would go over every nut and bolt on the car...

[Wageslave]

The motors idle a little warmer (6-9°F), hold 1500 rpm and they cool off to the thermostat temp. I would go over every nut and bolt on the car...

Thanks for the insight Wayne.
Every nut, bolt, hose, body panel.
I'm thinking I need to pull the intercooler to get a good look at the top of the engine to inspect all the lines.

[redfogo]

Call me crazy maybe I get lucky but I rented a coolant pressure tester filled my 818 and used it to open and close the thermostat tell the car was nice and full. I did the VCP mod as well.

I do this same process on my MR2 which is basically the same as the 818 and it also never has any bubble issues/overheating. Pressure tester I rent from any of the auto parts store.