2004 Scion xA Overflow bottle

Tiny
EWARREN
  • MEMBER
  • 2004 SCION XA
  • 4 CYL
  • FWD
  • AUTOMATIC
  • 56,000 MILES
The overflow bottle constantly overfills and causes antifreeze to spray out through the cap on the overflor bottle. I recently replaced the water pump and the radiator cap with Scion certified parts. I also noticed that the overheat temp light on the instrument cluster illuminates for a brief moment and then truns off. When this occured the cooling fan started up but never shut itself down like it's supose to. I was thinking that the thermostat had failed, but if it fail open the the engine would never reach ooperating tem, but if it fail closed the engine would over heat. What am I missing? Thanks much.
Saturday, March 13th, 2010 AT 12:38 AM

1 Reply

Tiny
CARADIODOC
  • MECHANIC
  • 34,415 POSTS
Sounds like a leaking head gasket, especially if you see bubbling in the reservoir, with no steam, before the engine is warmed up.

Your mechanic can verify this by performing the "sniffer" test. Air from the reservoir or radiator is drawn through a glass tube with dark blue liguid inside. If combustion gases are present in the cooling system, the liquid will turn bright yellow. That test should be done before spending any more money on parts.

Caradiodoc
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Saturday, March 13th, 2010 AT 1:23 AM

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