We have a problem .. having found oil in the water tank in our Scenic.
We had the head gasket replaced last September. The car runs fine and there have been no problems since the repair. The oil in the water was discovered when doing routine maintenance. The garage who replaced the gasket do not accept that the oil problem relates to the gasket - however this conflicts with the advice I am being given by an independent mechanic - who is very experienced. Could you please give me any pointers? The car is S reg - 1998. Thank you.
If the original problem was oil in the water when you had the head gasket replaced, then this could be just residue remaining from the original fault and collecting in the water tank due to the circulation of the coolant. You could try flushing the system with one of the flushing agent available from any motor accessory shop.
Oil in coolant usually indicates a leaking head gasket.However many vehicles will run for quite a while without any adverse effects (I've had a few myself over the years).
What many garages do is replace the gasket without having the head skimmed flat, or don't bother to tell you it needs re-torquing after say 100 miles (only applies to some engines)
Would be hard to prove after several months though.
Try some stop leak in the coolant for a tempoary repair
Why would they want to put Stop Leak in an engine that "run's fine with no problems"?
If it's not leaking that could make the circulation of coolant worse.
When you change a head gasket after oil/coolant mixing it's really hard to get all the residual creamy oil/water mix out of the system. You can get a coolant flush that cleans the system as reward4615 suggests and see how it goes.