Gurgling behind dashboard

This doesn't happen constantly, but sometimes when driving along, usually under acceleration, there is a "gurgling" noise that seems to come from behind the centre of the dashboard of our '95 3.9 V8.

The heater is working fine, but, my only thought as to what it can be is air in the coolant pipes??? If it is this, is there any way of easily bleeding the air out?? Or any other idea of what it could be???

Many Thanks

it may be low pressure in yer A/C if its fitted

Nope - no air con fitted

air lock in the heater matrix then.

That's what I thought it was. My next question is how to bleed the air out? Are there any bleed points anywhere?

make sure the heater is on the hot setting, then let the engine tick over till very hot, with no rad cap on.
(say 10 minutes or so)
then replace the cap. any airlock should be then gone.

Many Thanks . . .

will give that a go over the weekend

I would bleed ASAP. Air locks in other petrol engines can indicate loss of coolant, leak, faulty cap even due to head gasket failure.

If bled properly and air lock comes back then time to look at pressure checks etc

Makes sense as just had to replace expansion tank cap as that was faulty - suspect that has what has caused air lock