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Anyone have a copy of SB232024, covering coolant push troubleshooting? A good diagram of the cooling system's flow?

I'm working on an 04' AC330 that is pushing coolant.

Background: it's a customer's "new" yard-dog with 900k on the clock. It was losing coolant.

One of our mechs went and looked at it and found it pushing from the tank overflow. He tightened the coolant filter and it stopped. But it came back as losing coolant again.

Another of our mechs went and pressure tested the cooling system. Coolant bubbled out between the heads.

So, they drove it in and gave it to me to replace the head gaskets.

I did, and everything seemed fine. I opened the bay doors and let it idle while I cleaned up.

Bout shit myself when after a few more minutes fluid was pissing out near the back of the engine.

Jumped up and shut it off, found it coming from the overflow line.

Not sure if the level was where it needed to be, (one-piece tank) I let it idle some more to see if it would stop on it's own. Even though it was below the bottom of the filler neck.

Nope, just keeps going.

I've printed off SB215025 (Revisions) and I'm gonna run through that and see what's been done to the truck now. I do know that the inside of the water pipes wasn't pretty when I had them off. The manifold didn't look terrrible though.

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I went ahead and pulled the inlet screen out of the y-hose under the oil cooler. It was pretty well plugged up from the screened end to about 2/3 of the length down towards the flanged opening.

I cleaned it out thorouhly and re-installed it.
Put the fluid back in, less about a gallon, but enough to show in the sight glass and satisfy the low-coolant sensor.

Ran it at idle and after a couple minutes it was venting coolant overboard again.

Are there any other screens or spots like this that can get clogged and cause this problem?

Is there a spot to bleed the air out of the cooling system?

Asets water pumps can suck air and cause it to push coolant. Remove water pump belt and see if it stops pushing.

The Wabco/Meritor air compressors also caused it to push coolant. Bypass the air compressor coolant lines and run the truck.

These were the 2 most common reasons that I remember the Asets pushing coolant.

Ok, I pressure tested it and looked for leaks. Didn't find much, a couple hose dribbles that weren't sufficiently over-torqued.

I did re-test the cap and found it only holds up to 6-7 lbs.

Replaced that and (with the screen cleaned) no more venting.

Thanks gents!

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