After a few weeks of low-grade coolant loss (no puddles ever visible under the car), both cylinder heads cracked. Coolant reservoir never emptied and engine never overheated. Does anyone have any suggestions what might have caused this disaster? 1995 model, at 130,000 Km [less than 80,000 miles].
i would have to ask you where on the heads the cracks are? is the vehicle disassembled? the heads are at a machine shop? slow coolant loss, then? you could not find a leak so you pulled the spark plugs and pressure tested the cooling system to find coolant filling a(or many ?) combustion chamber(s)? or what?
NEVER heard of a cracked head (esp both) on ANY 928 from 1989 on (even race modified)...the year they beefed em up...much thicker and better material from 89 models onward.
Did you actually, see or find yourself, these "cracks"? ...if not, you may have been handed a line of BS(?).