If that fixes it then that was your problem. If not, then look into a pressure or chemical test on the coolant. Mine was always intermittent in the beginning, sometimes would hear the whoosing sound, lower heater output or erratic temp readings (all related to air/exhaust gas in the coolant - bubbles make the whooshing sound and the air bubbles reduce the heat transfer capability resulting in low heater output and erratic temp gauge readings). But then the problem would pop up more frequently until it basically did it all the time.

r.c.brown@ieee.org
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Project: 4Crawler
4Crawler OffRoad - 4x4Wire discount code