[GrahamBrown1]

Originally Posted by mcfe

The only reason I form it, is because it is true. I have communicated with many volvo owners of the P2 era, who had this kind of problem. And moreso when I myself had issues and contacted multiple shops who did not want to touch a volvo with a ten foot pole, because of head gasket issues, cracked blocks and depression of the headgasket unto the block because of overheating(aluminum is malleable).

When I had my radiator literally explode because of overpressure I took off the head sent it to get machined, 0.14mm were taken off the head. The block measured 0.05-0.07mm warpage, it should be closer to 0. I did not machine the block.

After reassembling I drove nearly 8 or so months before the next thing that went was the heater core matrix which exploded whilst idling. My hoses are once more becoming stiff. I plan to replace the cap with a Volvo original one and replace the oil cooler and thermostat(again) and if they still become stiff or I notice more oddities, I will know it's the block.

The R blocks are the same as the 140/170hp blocks. The difference is crank and pistons and possibly conrods(the NA 170hp versions share the same conrods as 4T3). Everything else is identical, down to the bore size which is where the problem lies. At 300hp it is guaranteed to crack. At 250 you will get cracks after some time but may last longer if you don't WOT. At 210 it is less likely, but not impossible.
The reason is simple, open deck design with thin cylinder walls.

Were are you from? Perhaps this is a local issue to you, as this is mainly a UK forum it’s not something we see regular over here I’m sure of it. Usage, fuels, environment may well be a factor who knows. Certainly strange.