Greetings everyone,
Going through a hefty program of new owner maintenance on my 1992 XJS (fluids, all coolant hoses, water pump, water rails, etc). Here is a picture of the thermostats that the previous owner put in place.
I have heard of people drilling one hole and placing it at the 12 o'clock position when the thermostats are replaced, but two (at 12 and 6 presumably)? Has anyone done this or seen it before? Just curious.
Charles

 

Those holes are way too big. The purpose is to let air out from behind the thermostat, so it goes at the top, as air rises through coolant. Hole diameter should be in the 1.5-2mm range.

Also make sure the "foot" that blocks off the bypass is deep enough. The Waxstat ones you buy at a Jaguar dealer are deep enough and don't block off the bypass. That means a large amount of coolant simply circulates in the block and never goes through the radiator. Grant has done a writeup in the stickies of the depth you need. which is at least 42mm, I used Gates 33188S

 

Jagboi meant to include the word "NOT"!

 

Good catch Greg, that's is indeed what I meant.

 

Understood! I read Grant's report on thermostats.

Still can't figure out why previous owner drilled two holes in the thermostat.

Charles

 

Charles,

Simple Aussie shade tree stuff from the 1960's etc. "If its running hot take the stat out, or drill holes for more flow"

Clearly they were/are chasing a clogged radiator, and YES, in those days, and car technology, you could do that to get you home, GUILTY is me.

Later stuff, NAH, the EFI system would have issues, as would many other things, but to some people, old habits never die.

Your catch up is addressing what they patched up, well done to you again.