Questioncar starts fine runs for a bit then just randomly stalls when i slow down for junctions only ever happens when revs drop, driving along with revs runs fine dipping clutch can cause this problem ,small deposits of gunk oil on cap creamy but no lose of water or oil been using it for a year since spotted could this be some sort of condensation
AnswerCheck for oil sheen on the water in the expansion tank.
That would indicate headgasket on it's way out.
[any water in the engine is bad, it leads to corrosion and reduces the effectiveness of the oil]
Condensation can accumulate in the engine, especially if the engine breather hoses are blocked - exhaust blow-by from the cylinders contains some water, if it cant escape it will eventually condense.
This slight pressure in the block caused by blocked breather hoses can affect the vacuum sensed by the ignition and result in incorrect timing which in turn can stall the engine.
Check the breather hoses are all clear.
{IF THEY ARE FULL OF YELLOW SLIMY GUNK}
wash all hoses/connectors (maybe even the rocker cover) in paraffin or some other good degreaser.
Once this is done I'd use an engine flushing fluid as directed on the tin and then change the oil and filter.
Quick motorway dash - 10 miles@70mph
All should now be well -
{If the breather hoses are clear} - post a follow up question.}
