Varied driving, does see boost a fair bit.

Well if it's a bhg, the load @ idle may not be enough for it to overheat. Best way 2 really know is to drive it & give it some boost.

As for sitting, mine was dead on 85C for 1.5hrs on idle even with a cracked block & bhg. Stock gauge won't move till over 100C anyway.

As for him saying to use green, I'm honestly shocked such a Toyota enthusiast would say such a thing. Should be red. Green won't cause immediate problems, mainly in the long term. Green coolant isn't the problem, but it's not right.

Unfortunately for you Id be leaning towards a blown head gasket or cracked block with what you've described

I'd agree. It's known to happen with Gen2's. Doubt it's a cracked block since I don't think you're pushing a large amount of power.

I also highly doubt that green will cause an issue. But thats pretty dumb if he knows MR's :(
 
But did you change the engine oil at all or get it flushed ?
Let me share this with you Toyota Corolla > 600,000 kms no issue in its life except for 2 alternators 3 batteries one starter.
Service says oil sludge in the sump, recommend total flush . 1 hr latter dead engine head gasket. He killed her

BHG or cracked block even though it had a comp test and pressure test?
Well that's just peachy. No one would happen to have a gen 2 long block for sale?

I'm having one of those top gear Jeremy clarkson pre challenge moments. "changing a blown head gasket? How hard can it be?"

Rizo has already named the mechanic involved (on page 3).
There are clearly no guarantees on 20 year old (complex) cars.
If the mechanic has done the best he can, that may be all that is required, however irritating that may be.
I suggest he describes the problem he is now facing and an outline of what he has paid for so far.
 
 

it's also possible the head is lifting under boost, hence why your not seeing issues at idle etc, but after giving a bit of a hard drive?

No guarantees? I didn't ask for any gaurantees. I asked for an honest effort not the piss poor one i got. I asked for specific parts to be replaced not for him to replace anything he damn well pleased. I asked for a specific issue to be resolved and I got more problems with the car now than before I took it to him in the first place. I asked to be treated like a human bieng not like a piece of s**t. Tell you what let's do a little experiment. Come to my house, give me $2000 and I'll laugh in your face and call you a bitch. Because essentially that's what happened to me. Then we will see what tune you will sing. Or better yet PM md and get the whole story before you make your judgement.