Volvo Owners Club Forum - View Single Post - Engine: T5:

Penguinistics · Jun 18th, 2009, 21:03

Easier way to check this - Have a look at the top of the piston - you can just about do this without taking the engine apart - If the surface looks almost crystaline all is well, if it looks almost smooth / semi-polished this is generally an indication of water getting into the cylinder - just like the momentary rough idle when starting from cold. Another thing to look at is the burn colour on the spark plug electrode. The cylinder that is "different" definitely stands out. If the rough idle clears up after a second or two then the water leak is not very significant (yet).

FYI, whilst this sort of failure eventually erodes the cylinder head sufficiently to cause a head gasket failure and significant coolant loss before that you will find the coolant system being pressurised just like with any head gasket failure. Is there evidence of this?

Incidentally if your water pump is leaking it would be very difficult to see it being driven, as it is, by the cambelt and also being hidden down at the bottom of the engine. Pretty much everything is in the way. A water pump leak coiuld easily loose as much water as you describe, but it is also something you don;t want to fail as it will probably bugger the cambelt and therefore the engine at the same time. Are you due a cambelt soon?

Jun 18th, 2009, 21:03	#3
Penguinistics VOC Member Last Online: Nov 20th, 2021 22:30 Join Date: Apr 2009 Location: Preston	Easier way to check this - Have a look at the top of the piston - you can just about do this without taking the engine apart - If the surface looks almost crystaline all is well, if it looks almost smooth / semi-polished this is generally an indication of water getting into the cylinder - just like the momentary rough idle when starting from cold. Another thing to look at is the burn colour on the spark plug electrode. The cylinder that is "different" definitely stands out. If the rough idle clears up after a second or two then the water leak is not very significant (yet). FYI, whilst this sort of failure eventually erodes the cylinder head sufficiently to cause a head gasket failure and significant coolant loss before that you will find the coolant system being pressurised just like with any head gasket failure. Is there evidence of this? Incidentally if your water pump is leaking it would be very difficult to see it being driven, as it is, by the cambelt and also being hidden down at the bottom of the engine. Pretty much everything is in the way. A water pump leak coiuld easily loose as much water as you describe, but it is also something you don;t want to fail as it will probably bugger the cambelt and therefore the engine at the same time. Are you due a cambelt soon? Last edited by Penguinistics; Jun 18th, 2009 at 21:07.