BMW 5-Series E39 (1996 - 2003) - 97 2.5 rad pressurising, is it a w/p problem?

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Wed 21 Oct 2009 17:38
97 2.5 rad pressurising, is it a w/p problem? - carnut1980
my rad boils over and spews from the top, it isnt damaged and the cap is on fine. Should i bleed it first before worrying about the water pump? does this happen a lot on this E39 model? it had been driving fine, lots of history and a recent new head, 145k, help!
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Wed 21 Oct 2009 21:59
97 2.5 rad pressurising, is it a w/p problem? - Andrew Moorey (Tune-Up)
These engines run a high pressure system and condition of the rad cap is of paramount importance. If its weak it will let the system boil up as yours is doing. First port of call then bleed the system. As you rev the engine you will notice the big hoses can be felt to actually swell slightly with the pressure, if not the pump may have lost its impeller but you will not have much of a heater either.
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