As some of you know, I’ve worked for 3 Subaru dealers over the years starting back in the late 70s. Subaru was having head gasket issues starting in the early 70s.
I’ve done more Subaru head gasket replacements that I can even begin to remember and have never had one come back on me for a failure. OEM gaskets, aftermarket, whatever; I’ve used them all.
Just my humble opinion, but I blame the problem on lack of a head bolt retorque and the elimination of 2 head bolts by going to 6 total.
Anytime I did a head gasket job I allowed the engine to sit all night. The next day the head bolts could be cranked down a bit more due to loosening slightly from gasket crush.
Something to keep in mind. The only time Subaru did not have a HG issue (excluding overheating…) was between 1977 and the mid/late 80s.
Why? Because Subaru recommended a head bolt retorque after a run-in period.
In the mid 80s Subaru said that the hydraulic lifter engines no longer needed to be retorqued BUT the mechanical lifter engines did require this.
So what happened during this period? The hydraulic engines started leaking whereas the mechanical ones did not. Subaru’s fix was to retorque the hydraulic engine head bolts also.
The engines back in this era also used 8 head bolts instead of 6 and some models actually had 10; 8 large and 2 small.
Just some trivia for what it’s worth… 