Cooling System Pressure 34#s ??? | Forums BMWauto.net || BMW AUTO - cars, motorcycles, tuning, ads, photos  
 

  Home    |    BMW website    |    BMW History    |    Contact us    |
  FORUMSbmwauto.net BMW Disscussion forums || www.bmwauto.net/forums
   Menu
   General BMW
    BMW 3-Series
    BMW 5-Series
    BMW Z-Series
    BMW European Delivery
    BMW FORUMS - home page

  What's Going On?
There are 39 guests on-line

  BMW Forums » BMW discussion forums » General BMW
  Cooling System Pressure 34#s ???

 Cooling System Pressure 34#s ???



What is the max pressure in a 1990 535i cooling system?

My cap lets off pressure at 34#s. That seemed excessive so I dismantled the thermostat and cut off some of the spring to reduce max pressure to 14#s.

Well, that was a mistake . "The Boss" called from the interstate when the car boiled off the coolant and the temp went up.

This is a HIGH milage car (270,000) and I am sure there are head gasket issues. Car normally does not overheat but hoses get very firm. I am also having coolant seeping problems around the hose connections (Orange lifetime antifreeze)

THANKS!
   Reply » Cooling System Pressure 34#s ???

I've got to ask. Why would you assume that the engineers at BMW would arbitrarily put a cap on that allowed excessive pressure?

What makes you sure that there are head gasket issues? Is the oil milky, are you losing coolant with no visible leaks, are you blowing steam out the exhaust...?

   Reply » Cooling System Pressure 34#s ???

Tangent
I have no idea why the 535i's cap does not release pressure untill it reaches 34#s, seems like a lot of pressure for a rubber radiator hose. My original cap and the new one released at the same pressure so I assume they are good caps???? I do know 14#s reduces the boiling point too much
That is why my original question asked what the max coolant pressure should be on a 535i.

I was leaning toward a blown head gasket because of the excess cooling system pressure. No milky oil or coolant smell in exhaust. As far as I can tell, no coolant loss except from the leaky hose connections (due to what I consider too much coolant pressure)

Engine has now developed a cold start miss at idle (for about 1 minute). After further checking I found a coolant fouled #4 plug with slightly less compression on that cylinder.

Head is comming off this week.

Expecting the worst (cracked head)and hoping for the best (blown head gasket)


BTW: BMW had a recall on early 325e (not sure if your 88 325is was recalled) to replace resevoir caps because excess pressure caused some heater cores to rupture.

My Ford diesel cap is rated at 13 lbs, the Vette's 17 lbs. Excess coolant is released into a resevoir.


Page 1 of 1

1



  BMW Forums » BMW discussion forums » General BMW

 

Forums BMWauto.net (c) 2001-2007