BMW Cooling

Important Information about Cooling

Over the years we've seen many cars unnecessarily damaged thanks to cooling problems. In a lot of cases it has been something simple which has caused a lot of damage because the owner of the car has not kept an eye on what is going on under the bonnet.

In one case a 7 Series came to our workshop with an owner diagnosed problem of a faulty coolant level sensor. In fact, he hadn't read his handbook and had been topping up the power steering fluid with water. Of course, by this point the car had a cracked cylinder head because of the heat.

It is very very important to check coolant levels (and oil!) before going on trips. However, if you are experiencing cooling problems or have replaced some parts of the cooling system it is advised that you check the following items:

  • Age hardening
  • Split ends & cracks
  • Cracks in plastic water elbows
  • Jubille clip crushing
Fan & Fan Clutch
  • The fan should have all of its blades
  • The fan clutch should cut in at the correct temperature to ensure correct cooling
  • The fan should not free-wheel when the engine is hot
  • The radiator should be 100% intact without corrosion or damage
  • Check cooling capacity with a flow test (any competent radiator reconditioner will do this for you)
  • The inside of the radiator should not be furred up (note if you are in a hard water area this is more likely
Header Tank
  • Check nylon tanks for splits due to pressurising or old age and check soldered joints/mountings on metal tanks
Radiator Cap
  • Check that it has the correct pressure release (if plastic type)
  • Check the rubber seal is not split/perished
Heater Valve & Core/Matrix
  • These often leak unknown to the driver. Check for wet carpeting around the centre console
  • It is essential to use a good quality antifreeze with a corrosion inhibitor

All engines, when filled with water/antifreeze require bleeding to allow trapped air to escape. The bleed screw is often on the thermostat housing. If air is trapped the coolant cannot come into contact with the metal surface to dissipate heat, this is where problems can begin!

If you have to add water to your engine check why.
Do not add cold water to a hot engine.
Do not attempt to drive the car if the engine is over heating.

If you're having problems, our section contains lots of useful literature to help and our parts department can supply most of the parts that you could require to do any job! If you get in a real mess... our workshop can sort out most problems! We have customers who bring their cars to us from Southern Ireland and France!