Well, looks like coolant was lost again. I understand there could be 3 reasons for coolant loss.
a) leaking hose (not the case as you can't see it on the floor)
b) Leaking head gasket seal
c) hairline fracture in the block (head is new)

How do you differentiate "b" from "c"

Thanks.

sorry, forgot to mention that most of the time, some coolant accumulates in cylinder 3 (3rd from passenger side)

You need to pull that head and see what you got.

Blocks almost never leak like this, especially if the leak puts coolant in the cylinder above the piston. Your mechanic has never put the head and head gasket on properly. It'* likely leaking at the head gasket. It could also be that the head is cracked. It will react to being out of coolant way before the block because it it on top and the coolant wants to go down. The head is also on top of the combustion process, so it gets hot a lot more quickly than the block when low on coolant.

I would do a head gasket test. When it comes out positive, I'd take the head off, straight-edge the block and head. If either are warped, machine work might fix it, but there are very narrow limits to this. Once everything is confirmed straight by a qualified mechanic or a machine shop, I'd do this:

1. buy new head bolts, keep them in their package
2. clean all of the oil out of the head bolt holes in the block
3. Have a qualified mechanic or machine shop put it back together with a head gasket from FelPro and the new bolts with dry threads, being certain they adhere to the factory procedure

Even with this, I see no guarantees. This block and head have been tortured by all of these shenanigans. There might be other problems lurking.

"New"?

Never been out of the box and never been put on an engine and never been tightened down on an engine?

. . . or . . . very recently purchased then improperly torqued several times and ran low on coolant several times?

There are more than three.

Carefully remove the head. Check for damage on the head gasket, especially around cylinder 3. If none is found, disassemble the whole engine. Check it with the dye procedure by Magnaflux. May as well check the head while you're at it. You'll have to take it apart as well.

Magnaflux video said it doesn't work on aluminum

I can order the fel-pro brand
He has agreed to install for free.

Gm says not to oil the bolts (use dry) but fel-pro video says to oil the threads and the head of bolt ??

When you are using bolts and gasket from a manufacturer other than gm, do you follow GM instalation procedure and torque requirements?

The mechanic tested a few times (by running the engine then letting it cool) and it held the coolant for a day then again it started leaking. He says that the bolt threads seem to stretch after a day or so then leaks. Hopefully, will not happen with fel-pro (maybe?) Also, he said that cylinder head may be soft and that'* why this happens.

Here is the page of fel-pro bolt installation and this person says to oil the bolts?

​​​​​​https://www.rockauto.com/en/moreinfo...t=5308&jsn=486

Do it whatever way you want. I hold no hope for you..

Magnaflux dye procedure created by the Magnaflux folks for aluminum engines. Not their procedure for ferrous engines.

I told you what I would do here as a reference for a way to do this properly. If all that you got from this is [[color=#f39c12]order up a FelPro head gasket then do the same thing as you've been doing] then you didn't get the point. This so-called "mechanic" that you are using clearly will not be able to install any manufacturer of head gasket on this engine for you properly. I base this prediction on the history of what this so-called "mechanic" has done so far. The stories he has told you of other successes are not this repair, and this repair has gone so far South that the penguins in Antarctica can't even see it.

The video is generic, and mentioned no particular make or model of vehicle nor engine. Since the FelPro video we've both watched does not specify anything like a make or model of vehicle nor engine, it is, by default, overly generic in nature.

While we're here, I have to ask: Has it occurred to you that you wouldn't even be talking about oiling head bolt threads (yet again) if this so-called "mechanic" knew how to properly fix your engine? It is not normal for a non-mechanic customer to put in so much effort researching procedures for any mechanic, specially one with three decades of experience.

I'd follow GM'* recommendation, unless the aftermarket manufacturer notes why they use the alternate procedure. The overly generic FelPro video does not note a reason for an alternate procedure for your vehicle nor engine as it notes no distinction about any vehicle or engine, so follow the GM procedure for your specific video and engine.

Doesn't surprise me. I've lost track of which set of head bolts, what head gasket, and what torquing procedure he is using, but I haven't heard of it being done correctly even once.

Sounds like a bunch of hooey to me. If the threads stretch, then they strip. Threads don't stretch without stripping. He still hasn't torqued it down properly

I hope it won't, but I'm sure it will. FelPro is not another word for "magic". This "mechanic" appears unable and/or unwilling to torque this engine down properly, and has likely damaged things so much that it is impossible to assemble it properly now.

It'* soft, eh? Like softer than the other heads out there? I thought this one was brand new . . . ? How soft is it? What measurement is he using for this dubious speculation?

While we're here, I never saw an answer to this question about the [new head]:


While we're reading stuff over at FelPro.com, Here are a couple of quotes:

Sound familiar?

Sound familiar?

Sound familiar?

Rubber head bolts. I can't stop laughing. Thanks man.

I have bought new GM bolts each time. The head was new and when the coolant leaked and mechanic said that head may be warped, we had taken it to machine shop and had it tested and was determined to be fine. I have asked him to check that head and block is flat using straight edge and feeler before installing new fel-pro gasket and bolts.
I have also advised him to clean bolt holes of oil and should be dry before installing the head and bolts. I hope the threads in the block were not damaged when he had overtorqued bolts to stop coolant leak. I don't have more funds for this car so hope it works. He has the sequence of bolt tightening pattern and torque requirements. I have also given him Cathedralclub'* instruction part as a guide.