Your mechanic does not know what he'* talking about. There have to stretch and clamp in a specific way. If it were OK to do it in two turns they would say go 90 then 50 or what ever. That is a different application.
No wonder he has nothing but problems. He doesn't do it right and refuses to change his ways. He will continue to have problems and so will YOU.
Get another mechanic.

One motion. There should be nothing in the way. If there is something in the way, a high-quality impact extension that is no longer than the necessary length to clear reasonable obstructions can be used.

​​​​​​​Yup. Agree.

​​​​​​​He insists a lot of things. Then your engine is bad again each time.

The harm is that he'* spitballing alternatives to the procedure. What is his reason for 90 then 65? Is this the magic 58.0645% then 100% combination that is the perfect answer for torquing everything? I doubt it. Why not 85 then 70?? . . . or 80 then 75??? . . . or 75 then 80???? . . . or 25 then 50 then 40 then 30 then 10????? . . . or 10 then 72.5 then 72.5??????

I can make up random combinations of numbers that add up to 155 without ever looking at a service manual too!

​​​​​​​Yup. Agree.

. . . or here'* an alternative answer that might be more palatable to him: Tell him to do whatever the heck he wants as long as it never leaks again until the end of time, and as long as it is repairable by the next mechanic through standard parts and procedures, and as long as it runs properly for at least another 50,000 miles. Since this is his big experiment, wholly funded by you, to research what improper procedure might have a chance of working because that'* what the world needs, then maybe after 500 more tries he'll stumble upon a better answer than the one proper procedure that he refuses to try. I just checked at RockAuto.com, head bolts are $73.79 each but they only have 181 sets in stock. My my calculations, that will keep him busy until early 2025 when they might get the other 319 in stock. The web site says they don't discount on orders of even 181, but I bet if you called them you could get a bulk discount of some sort.

He'* likely damaged the block, head, pistons, valves, bearings, timing chain, starter, and battery by now anyways. I have a hard time imagining that it will work right no matter what he does . . . until he replaces all the damaged parts and then reassembles them properly.

Yup. Agree. And get a refund. And get compensated for all of the other parts/tows/coolant/time/etc. you've had to endure.

The 90 +65 was an example only. I was there and he would use different combinations to add to 155 depending on what position his wrench is at. I spent money on high quality parts repeatedly hoping to have a good product that I can use for many years but this may be overly optimistic as I can see the engine deteriorating.
Just as importantly, I have promised a vehicle to my son that really needs it for his practicum and work but I have let him down several times already.
If it doesn't get resolved this time, it is time to move on. Not only is this not good for me, but is also discouraging to him and a waste of his hard work.

I agree. Not good for anyone.

Please let us know how it comes out!

Yesterday he told me cylinder head was warped and was going to take it to machine shop likely at my expense. But today he tells me that there is a hairline fracture in one of the cylinders. I am tired with this and was thinking of using Rislon Head seal and Gasket repair. Anyone use this before with any success? Is there a sleeve in the cylinders that can be replaced to stop the leak?

Your expense because you bought it new and he ruined it?

Not surprising.

No magic juice will fix this engine. It'* too far gone. Especially with a cracked cylinder.

Might be able to re-sleeve it, but it'* probably cost prohibitive. Either way, I see zero evidence that this "mechanic" could put it together correctly if you did get it re-sleeved.

There'* likely other damage that nobody has diagnosed also.

Do yourself a favor and either sell the vehicle or get a different mechanic to install another engine.

CathedralCub wht is hairline fracture not surprising.

I called the manufacturer Rislone and the tech thought that their product "Head seal and head gasket repair" would likely seal the fracture but you don't think so..have you had any experience with this type of product. The tech didn't think the product would clog heater core as the engine is new .

After the mechanic had "fixed" the engine, it was working nicely except the water getting into cylinder..If this can be resolved then maybe...

Comming up with cash and for another engine and install is challenging. Trading car in gets $500 if not working.

I can get 2010 equinox engine at good price but I think my engine is newer and some small differences may exist.

They sell that stuff and make claims that will not hold up under scrutiny. A head gasket that'* starting to fail may get a short term relief from some sealers but you are not going to fix a crack with it at all. Cracks need to be repaired.

A local mechanic said to use Irontite, he said that truckers use it. (I know you guys don't think these sort of things will work) ..This mechanic seemed to think it might if done correctly.. I just need my car to work for a while so I can trade in.