Eaton's 818C Build - Power Window Modifications

[Mark Eaton]

What worked for me was a 137 kPa cap on the radiator and a 108 kPa cap on the expansion tank. I capped the tube next to the radiator cap and ran a 5/16" hose all the way back to the expansion tank from the radiator breather pipe that was on the right side top of the rad. At the front of the engine I used something like this:
https://www.amazon.com/Radiator-Atta...s%2C178&sr=8-9

in lieu of the Wayne mod. I ran a hose from that to the expansion tank with a tee in it to pick up the hose coming from the radiator. The plastic overflow tank I put in the engine bay and ran the overflow from the expansion tank to in the top and down to the bottom so it will suck the coolant back into the ex. tank as it cools.

When I filled it all, I put the back of the car up on jackstands so the filler neck of the expansion tank was the highest point after filling the radiator and the side pipes as much as possible level on the floor. I used one of those filler funnels you can also get on Amazon. It all worked out really well. Thanks for ideas MRG Motorsports and others. I did throw a code for coolant sensor voltage high, but that went away after 50 miles or so. I think that was because I also put in a heater under the dash and it took a while to run the bubbles out. It always runs right in the middle of the temp gauge. I got the fan to come on for about 15 seconds after idling for 22 minutes and the front coolant pipes get hot in just a few minutes.

Reading your post again, yeah, I think you're gonna need an expansion tank to make it work right. The key I think is the high pressure cap up front and the lower pressure cap at the rear tank. Make any expansion and bubbles happen back there instead of at the front which is lower.

Ed

Thanks Ed, I'm going to have to read this through a few more times. I don't have the radiator breather pipe on the right upper side of the radiator as my donor was NA and not turbo.

[Bicyclops]

Do without it then. If you fill the radiator with the car level or even with the front raised some and keep filling it until the side pipes are as full as you can get them, cap it and then lift the rear, and you shouldn't have any air in the rad. With an expansion tank the highest point, fill it until it bubbles no more and then start it up and keep filling it. With a bleed at the hot water exit from the engine (high point of the hot side), you should be able to get it all. The expansion tank is going to need a drain back to the water pump. The NA water pump might not have a fitting for that and you might have to tee into the "oil cooler" return or the heater loop return.

https://www.subaruparts.com/v-2002-s...and-components
There's the expansion tank. It shows 2 radiator caps, #13. The round one is for the rad and the one with ears is for the expansion tank.

Ed