Bleeding Green: Getting the air out of a EJ22 Subaru conversion

[dorje]

OK, this was really not easy, so I aim to save you, dear reader, much time, frustration, and swearing.

I have the Kennedy petcock on the radiator, and the Burley coolant pipe in the back comes with a bleeding petcock as well. To get air pressure I have a small tire inflator I got off Amazon that plugs in to the 12v cigarette lighter port, which I put up to the overflow port of the expansion tank cap and turn on.*

First off get as much coolant in there as you can. Open the front bleeder, pour coolant in. Push through with air pressure. Repeat until liquid comes out the front. Close the front, open the back petcock. Push more coolant through. I was on hills in various orientations, I jacked one side up, don't remember if it was front or back at that point. That was the easy part. The coolant return filled up pretty easily. It may help to have the van a little warmed up so the thermostat opens.

After getting coolant coming out the radiator pretty easily with a little air pressure, drive it on some hills, rev the engine, open the front. Turn the van off, wait a minute, more air pressure until air comes out the front. Repeat. Try with the heater on to get coolant through the heater line. You may have to open up the bleed screw under the rear seat, but usually this is self-bleeding so if you have hot air back there don't worry about it. Also try stopping the van with the passenger side a little higher than driver side, and then bleed that way.

Feel the coolant send pipe, the one that should be hot. Is the whole thing hot? Where is it hot, where does it stop being hot? For me, even after all this driving and revving and pressure, still there was a bubble in the first big dip of the SS coolant pipes after leaving the engine that it just couldn't pump past. Having the heater on in the back here in January mostly kept it from overheating, but the radiator and most of the send pipe was still dead cold.

So, taking Terry Kay's advice from another post, I parked on a hill with the nose up then jacked up the nose as far as I could. Turn on the engine, put the Bentley on the gas pedal, open the radiator bleeder until coolant comes out in a clear flow with no bubbles. Cut the engine and wait a minute! (When I waited, I watched the coolant geting sucked back into the expansion tank, and I watched a really big bubble get pulled out of the coolant pipe.) Then I pulled off the overflow tank hose, pushed my air compressor up to the expansion tank cap, pumped it up to 10 PSI, walked around to the front and bled out the radiator again.

Feel the radiator: hot? Coolant send pipe hot? If not, repeat.

For me, getting the bend of the coolant pipe where it dips down as close to horizontal as possible was the key. YMMV but hopefully this helps someone to spend less time than I did getting your system bubble-free.

Now to install a lower-temp thermo-sensor. My fan should be coming on way sooner than it is.


* Do not exceed 15 PSI! I went up to 30 PSI and cracked my coolant level sensor.

[supdude]

What is your coolant routing method? Reversed manifold? I'm running the Kennedy coolant routing with both of Burley's coolant pipes and pretty regularly bleeding the system due to faulty coolant pressure tank caps.
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['83 EJ22]
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[dorje]

Yeah, I had Tom Shiels reverse the manifold for me when he did the wiring harness. I must've gotten lucky with my coolant pressure cap, I've heard some stories of faulty ones. You sure the pressure cap is the way air is getting in / coolant is getting out? I didn't realize my coolant level sensor was cracked until I pulled it out and inspected it. I actually bought a new expansion tank, luckily I get to return it.

If you're overheating check if all heater hoses are hot, and if the radiator send hose is hot. Also if you've got a Kennedy conversion make sure you know where your coolant bypass is. The Subaru engine needs a coolant bypass so the coolant on the return side will warm up enough to open the thermostat and start actual coolant flow (this is a feature so the engine warms up faster in cold climates). By default Kennedy doesn't specify to plumb a separate bypass so you have to keep the footwell control lever open at all times (bottom lever?). Shiels sells a nice sandwich adapter that bolts onto the water pump and pipes a small output from the coolant manifold directly to it. (I have an almost-new one for sale if anyone needs one.) Buslab switched me to their method, where they splice 2 tees into the heater lines and connect them directly together. Not sure if it's near the front or the back.

[dorje]

If the radiator send line is warm all the way to the radiator, then check if the radiator is hot, then check the return line to see if it is warm (not hot, not cold). If the return line is too cold your radiator could be clogged.

My fan hasn't been turning on at all, so I thought it was a fan issue. Tested the fan by jumping the connections of the plug, the fan turned on great. So I figured the thermo-sensor wasn't switching properly. Bought a new thermo-sensor, but same issue. So either the temp sender is off or the radiator is clogged.

(Verified the original thermo-sensor in boiling water: it was working.)

[tates1882]

What do you all consider normal operating temp? Mine runs at about 186° the fan comes on at 205. I have reverse manifold and bypass. Haven't had any problems with air bubbles in the coolant system either.
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88 Vanaru, ej22, naht

[dorje]

'96 2.2L operating temp: 182°F (source: Somebody on the Yahoo Group)
Stock Vanagon operating temp: 188°F

My temp gauge stays far to the right, around 80% to the top. I shot the engine with an IR gun when idling: 204°F. Definitely higher than I like.

I'm using the original Vanagon temp sender rather than Subaru + resistor.

It's not overheating and the fan isn't coming on. It's like it's trying to stay at a higher temperature. I'd really like it at a lower temperature, partially because I just failed smog.. NO reading too high, which can be caused by high temps.

Here's my possible causes:
* Radiator partially blocked
* Thermostat not opening enough.

The fan isn't really coming on, except right after getting off the freeway. When I come to a stop at a traffic light, the coolant light starts to blink / overheat. When I rev the engine the fan kicks on and the temperature comes right down. Sounds like it's time to get the radiator flushed.

[edgood1]

I have a 97 ej22.. the single port exhaust one. Should be the same engine as yours. I run around 185. Going up hills I've seen it creep into the 190s and idling it gets up to 205 when the fan kicks in and brings it right down.

It took me a good day or two of driving after filling the coolant for the temps to stabilize but they've been steady Eddie since. That was 7 years ago.

I'm running the smallcar coolant setup with reversed manifold.
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