anyone ever had this problem????

[MUSKIE]

my rangie 3.5 efi expansion tank always seems pressureised, even after not using the truck for a few days and whenever i stop and turn the ignition off it spits water/coolant from the expansion tank overflow pipe.
the coolant is relativly new and of the correct mix, the temp never gets above half way and she runs lovely. sometimes the expansion tank water level light comes on saying it needs coolant but can go out again and not come back on, even though i havent topped it up. the water tank switch is new as i thought this was the prob, the radiator is in excellent order.
could this indicate a thermostat problem or air lock, also when i rev the engine i can hear bubbleing water rushing about behind the dash, oh and the heater works very well.
any ideas guys :?  :?

[SPIKEY]

Hi Muskie.
              Drain the cooling system from the bottom hose.

Take the top hose off the rad and "reverse flush the rad " i.e. insert a hose pipe into the bottom pipe of the rad and watch all the muck flow out the top.
Test the thermostat by removing it and dropping it in to a kettle of boiling water. If it opens, it's working.
The hose can be used for flushing your heater matrix.
Remove the pipes that go through the bulkhead and again watch the muddy water flow out.
Finally, top the system up with water and bleed so there is no air in it and you should be o.k.

If the symptoms are still there, your head gasket is kapputt !!


Cheers,

SPIKEY.

[nzrover]

I'd be replacing the rad cap to start with - the gurgling may be boiling in the cooling system due to too low a pressure..

[diesel_boy]

all so  take out all ya spark plugs and see if one is very clean youcould have a loose liner in your block allso    all so if you need any v8 bits  i got load  got 2 compleat engines  3 sets of heads loads of carbs  no su's tho

[MUSKIE]

thanks guys, i really dont like the head gasket theory  :shock:  i know radiator is clear as it has only just been flushed both ways, didnt do matrix so that is a consideration, i wll try the thermostat and rad cap first.

[Range Rover Blues]

Better a head gasket than a loose liner!  Start, as suggested, with the easy stuff and make sure you fill the engine through that little bung in the pipe to the heater matrix, nice and fast, to drive out any airlocks.
If you have got a clean plug then one cylinder is using water.

On the plus side if it's holding pressure for a few days then it doesn't leak!

Don't worry about the level warning light, ours goes on when going round corners, it uses a magnetic proximety switch so it's not that accurate.

Also remember an engine will heat up once stopped, for about half an hour, so it's not uncommon to see some expansion when you park up, could just be coolant that's splashed onto the rad cap or too much coolant in the system, nearly all the air is driven out of the expansion tank when the engine's hot.
Like I said, do the obvious and try not to think the worst just yet.