MGJohn wrote:
A full service history means little if that servicing has not been done correctly, particulrly where coolant change or draining is involved..
Many so called cylinder head gasket 'failures' on K-series engined cars follow soon after dealership servicing. If the coolant is changed as recommended by all manufacturers, if then the system is not bled correctly in the sophisticated little K-series, particularly on cars asked to frequently punch above their weight, then a 'failure' can occur soon afterwards.
It is no coincidence that many failures occur soon after a professional service. Here I speak from experience, not of my own K-series cars, but some of those owned by other drivers I know.....
I've changed the coolant on a few K-series and noticed one thing recurring. The little valve in the inlet manifold with the tiny ball bearing blocks up. It doesn't become a problem until the coolant is disturbed and the system needs bleeding.
With it blocked it can be a pain to bleed and even when it seems to be bled properly it might not be, but there could be an air bubble at the top of the head cavity, ready to cause problems the first time the car really gets warmed up or the air moves and causes an air lock.
I'd go as far as saying that the symptoms of this valve being blocked are more likely to be taken as HGF by a lazy mechanic, thats if the air bubble in the head hasn't already caused HGF by this point.
When I've cleared out these valves and re-filled the coolant I've never had one that hasn't bled perfectly straight off.
Why do these valves block up? Simple, the cheap steel radiators Rover used until the turn of the millenium were crap and rotted, this valve is the most vulnerable place on the engine.