I bought the compression tester from Harbor Freight last year...it said it was good for the 6.5. well, it's not; the adapter for the 6 5 doesn't fit into the opening. Can I just buy the adapter that fit into the glow plug hole somewhere. what works for you guys? BTW diesel is at 3.79 all over the greater Seattle area right now. Ouch. the 3.44 b99 I can get seems like a bargain

There are decent testers out there for less. I bought a set with a bunch of adapters for different vehicles years ago and it was under $50 at that time. I know they haven't gone up much, even with the increase in diesel popularity.

I used the harbor freight compression tester, it worked fine on my 6.5. adapter # 11.

In the big kit, there are three 10mm adapters, #11, #12 and #14. # 11 is 2 1/2" long, the #12 is longer and courser threads, #14 has the long hex.

The intsructions do not match the adapter placement in the case and is no correct on the applications. The instructions show #12 as the 6.5 adapter and that adapter only fits in the # 14 slot in the plastic case.

I did have to clearance the manifold on a couple glow plug ports to get the coupler on the adapter.

The long Hex one (#14 in the case) would have solved the manifold clearance issue, but the tip is too short and does not seat fully in the glow plug hole. Cutting back the hex a 1/4" on a lathe would probably fix it.