I was recently looking at a GTV Twin Spark which looked to be in decent shape until I unscrewed the oil cap and found some milky looking oil around the grooves of the screw cap.
I am aware that this generally means that the car has a blown head gasket - but I wanted to know if it could be caused by something else and if there are any other ways of verifying that a head gasket is indeed blown?
The car had full service history and I would have expected that a problem of this magnitude would have normally be detected by a technician.
If the car is driven infrequently, (or just on short trips), and the engine not allowed to reach operating temperature, the milky oil could just be from condensation.
Check for oil in the cooling system, too.
Is that cause for concern?
I'd say oil in the radiator would confirm a blown head gasket.
Re the condensation thing: if you could check the oil cap after the engine has fully warmed up, and the milky residue is still present, that would also confirm the HG is on the way out.
Either way, tread carefully.
Check for tell tail signs of other problems that is likely to cause the HG failure. e.g. recent water pump replacement, new radiator or radiator hose etc. Head gaskets don't let go on their own. As what fuel they use.
Of course check for oil in the coolant and then do a hydrocarbon test.
If the car does normal mileage it very likely to have a blown HG,
It does have the typical amount of k's for its age. If the seller did agree to repair it, would I have to worry about other long term effects that may have been caused by a potentially blown head gasket?
Did anyone have an answer for this question?
No, but only if the job was done thoroughly. i.e. everything that was damaged is replaced or repaired. Also you need to find the reason for the head gasket failure in the first place.
With service history, you have to remember that a stamp in a servioxce book is a good sign, but it is what other work is actually done that is important - or more precisely what is not done.
The service report should details what was fixed and what is recommended to fix. Some people will show the book but not the receipts with outstanding faults not fixed.