the car uses no coolant ,replaced t stat water pump ,bled system when driving on 1995 BMW 325is

temp gauge goes to red ,no boiling fluid ,no fluid lose,no white exhaust or water in oil,but does lose heat in car ,and will go back to half way on gauge at the blink of the eye and have heat again ,could it be the temp sensor for the gauge

by in Potwin, KS on February 13, 2013
2 answers 9 comments
ANSWER by on February 14, 2013
Sounds like an air pocket in cooling system. Get a shop GOOD with BMWs to purge the system and check further for cause.
COMMENT by on February 14, 2013
went to red on last drive and let off the gas and went back to half on temp gauge ,does computer hold gauge in half position? doesnt appear to be overheating coolant just on gauge
ANSWER by on February 14, 2013
poss air pocket or bad temp sending unit or wiring for that sender
COMMENT by on February 14, 2013
went to red last drive and let of the gas and went back to half and continue on,does computer hold temp gauge in half position?
COMMENT by on February 14, 2013
no sounds like air pocket or no circulation thru radiator. have you double ck'd the coolant level since driving?
COMMENT by on February 14, 2013
yes its good.temp sending unit is on the left side of intake manifold?
COMMENT by on February 14, 2013
did you have this issue b4 you repl water pump? if so ck for blockage in radiator
COMMENT by on February 14, 2013
yes just started out of the blue ,so i replaced the t stat ,and water pump and bled the system and still does it ,but the coolant doesnt appear to be overheating just the gauge
COMMENT by on February 14, 2013
Air pockets will cause many funny symptoms , do you have an infrared thermometer? Does the radiator cooling fan cycle properly?
COMMENT by on February 16, 2013
idles fine temp stays in middle ,going 50 or 55 mph will shot up to red take your foot off the accelarator and drops back to middle
COMMENT by on February 16, 2013
Radiator is clogged. After it is fully warmed up , shut it off and check for 'cool' spots in the rad. core.Is the T-stat you used aftermarket or factory? The more you narrow down the symptoms timing, it's sounding more like a circulation problem to me.I think globalhelper is right.(Go Greg!)