Qsb-380 Coolant loss

[William Milanese]

I am on my second full year of ownership of a 390 sundancer. I’ve noticed a small loss of coolant on the expansion bottle with no visible leaks, oil clean without any moisture. I remember reading that it could be a problem with the turbo gaskets or cracks. I am ordering parts for my after coolers now and would like to address this issue now.
The after coolers were never serviced, one a total loss, one rebuildable

Topic

[William Walter]

Burping

I’ve been told to run engines with cap not fully locked down for a while to allow air to escape.

[Fireisland1]

I also been chasing a coolant loss [ 6 0z ] Turned out to be a hose connection at the hot water tank. I never thought to look there.

[David R Flamer]

Joe Monaco wrote:

After I serviced my heat xchangers it took several trips before my expansion bottles stayed fulll. I was sure there was a leak but there wasn’t. If you serviced those recently I bet it will settle down after a few more outings.

Happening to me right now. Pressure tested at 20 lbs all day. Zero leak down. Must take a while to burp out.
Is there any procedure to hasten getting the air out of the system, or do we just run it till it gets out?

[Joe Monaco]

I had the heat xchangers removed and cleaned. When I did that some if the coolant was removed then replaced when reassembled. The system took a while to “burp” all the air. While this was happening the overflow bottle had have antifreeze added several times before it finally stopped. I reread your post lookis like you ran barnacle buster so propably not the same as my situation.

1 user thanked author for this post.

William Milanese

[William Milanese]

You say you serviced the heat xchangers, you mean cleaned the tubes?

[Joe Monaco]

After I serviced my heat xchangers it took several trips before my expansion bottles stayed fulll. I was sure there was a leak but there wasn’t. If you serviced those recently I bet it will settle down after a few more outings.

1 user thanked author for this post.

David R Flamer

[William Milanese]

Hey Rob, thanks for the reply,
Yea the coolant looks clean as new, no signs of overheating and oil doesn’t show any signs of water. Aftercooler were only slightly discolored by the inlet. At the end of the season the temp would start to rise when running hard on this engine but no major overheats.
I decided to get into the coolers, pumps, major barnacle buster flush etc.
My hose from the main heat exchanger has a bad kink which could effect flow too

[Rob Schepis]

Is the coolant clean and clear or is it discolored at all? Any history of an overheat?

[Author]

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