These engines are suspectible to overheating so its imperitive to keep the cooling system in A1 condition. Let em overheat to many times and your head gasket blows.
The dreaded 'dancing temp gauge' is a problem too, usually caused by an incorrect thermostat, these donks need a dual acting thermo with a small hole that allows water to seap past when the thermo is closed. What happens during warmup with incorrect thermo is -
cold engine, thermo closed, coolant warms up, thermo opens, cool coolant comes thru and thermo closes, engine temp momentarily gies thru the roof, thermo opens again - this cycle continues a few times until stable - this isn't good for the head as it is constantly being heated/cooled.
A common reason for multiple head gasket failures on the one engine is skimping on the job, this donk uses Torque To Yield head bolts that are designed to stretch, in practise they are good for use once and throw away so if you get a head job enusre new head bolts are used.