dvg said:
Well...no one performed any pressure tests whilst trying to diagnose the
fault. One mech tested fan motor and something else electrical, others
only were checking condition of the cooling system (i.e. opening the
coolant reservoir).
Hope its al scheduled in repair procedure.
Thanks
All valid, but heres what you do:
starrt engine-if it will start. does it run on all 4 (3,5,8 etc)
if 2 are down then it could be blowing between adjacent cylinders.
remove water cap while still cold(for safety), and bring engine up to at
least 80 deg.
look for bubbling in the water, as combustion gases find their way into the
waterways.
if possible, get a frient to blip the engine while you look at the water, to
look for a sudden burst of bubbles.
You may also find that air will fill some high point then start forcing
water back, with the result that it overflows from the expansion bottle.
you can also look for these last 2 when the engine is hot, do NOT emove the
pressure cap, but stop the engine and listen carefully to the cap, it will
fizz gently if things are blown, as it does its job and releases extra
pressure. might also be weeping water. do not attempt to tighten in the
mistaken belief that this will cure it as these days they are only plastic
and theres a good chance you might break something. If you are the
optimistic type then you can buy a new cap. the only thing this will damage
is your wallet.
also look for water/oil sludge under the oil filler cap.this is pretty much
self explanatory.
I might add that all the above are things that you should check when buying
a car anyhow, as they are simple checks that only take a few minutes.
I dont know the details of pressure teting a head, as thats a specialist
job, but I know it involves cleaning the head, thenlamping it down to a big,
machined flat plate
then pressurizing probably through injector/spark plug holes. Maybe with
air, but a liquid (paraffin?) would make more sense. I too would be
interested to know the details.
Unfortunately, the symptoms of a blown head gasket are also those of a
cracked head. Lets face it, the heads coming off.
Mike