I agree wholeheartedly. At this stage, this "mechanic" is a scam artist at best. If it wasn't so sad it would be comical how this "mechanic" has you under his spell going in circles while he damages your engine worse and worse over and over and then makes you pay for it and take all of the risks.

Is this "mechanic" a real mechanic with a shop advertising and a receptionist and everything? . . . or is this "mechanic" a friend'* cousin'* aunt'* dog'* former owner that was recommended by the dog or something? I'm trying to not be offensive etc. I've been wanting to ask this for a long time.

The bolt and head gasket are brand new. He has torqued the bolts to 22 lbs then 160 degrees instead of 22lbs + 155 so pretty close to spec.
The amount of oil used was minimal this time after clearing the oil thread holes with air compressor. I had suggested not using oil but he said that you are suppose to use some oil ( I am not a mechanic so I had to accept what he said as he should be taking responsibility for the outcome)
The ambient temperature was between 5 and 8 degrees celcius not between 5 and 100 degrees.
We had the cylinder head checked (after the bolt had broken) and it was determined flat before his current install where he torqued to 22lbs and 160 degrees. What he suggested is not undoing the bolts and reinstalling but just turning the bolts a further 10 or 20 degrees in sequence that they are suppose to be torqued in.

The mechanic I am using says he has had formal schooling and about 30 years of experience. He has rebuilt a terrain engine and was advertising it for sale so I thought he knows my engine which is the same so I went with him. The engine of the terrain sounded good. He says that this issue has never happened to him as he has built this type of engine that worked out fine. He usually works out of his garage.

With oil on the threads this is not "close to spec".

Minimal oil is not [clean and dry] which IS the "spec".

That'* unfortunate.

Actually, you didn't.

. . . but he doesn't. He does things wrong, breaks stuff, blames everything except himself, then makes his customer pay for parts so he can do the same thing over again. This is carved in the annals of history.

I did not say the ambient temperature went to 100 degrees. Your coolant wasn't lost while floating in the air. It was lost between the head, the head gasket, and the block. You asked "Why did I lose so much coolant in the second half of the trip (mixed highway and city) . The first half of the trip was at outside temperature of about 8 degrees celcius while the second haft was at about 5 degrees."

My answer to your question was: "Those are pretty wide temperature swings, between 5 and ~100 degrees Celsius. That could have contributed."

The engine temperature ranges from ambient temperature for a low to the highest operating temperature for a high. The low is the ambient temperature of 5 degrees Celsius. The high is the engine operating temperature, which ranges between 82 degrees Celsius and 100 degrees Celsius coolant temperature. The head, head gasket, and top of the block experience higher temperatures than the coolant temperature as they directly face the combustion process, so 100 degrees Celsius is a good rough number that is easy to use as a general reference in a conversation like this.

Back to your original question: Why did you lose so much coolant? Because the head gasket and surrounding metals are experiencing temperature swings between 5 and ~100 degrees Celsius. This causes heat expansion and contraction as a normal part of thermodynamics and physics. With an improperly torqued head and gasket, these wide temperature swings can allow gaps that allow coolant to pass across the gasket where it wouldn't if this engine were put together properly. Are we on the same page now?

Okay.

. . . with oiled threads.

Which is an improper installation, not remotely close to proper, therefore prone to failure.

When? 30+ years ago? He says a lot of things that I don't believe. His practices on your fairly-modern engine are glaringly poor. Maybe he'* great at rebuilding all iron V-8'* from the `70s and `80s. That'* a different animal than modern engines that are designed with very little margin for poor assembly.

Then he should know what a torque-to-yield bolt is and how it works, and also should know to read the service manual and re-assemble how it says to reassemble. Since he does not appear to understand either of these, the "30 years of experience" part is irrelevant to this repair.

The way he has handled your issue, I am led to believe that he rebuilt that engine, didn't test it, and when he sells it and the buyer calls to complain of coolant loss, he will tell them that he'* not worried about it, and just keep adding coolant.

Cool! Then he can yank that engine out of the Terrain and put it in your car and do right by his customer that is placing a lot of trust and patience in him.

Then he'* done well as a mechanic for about 30 years and can afford to eat some repair costs to do right by you, right?

LOL

Not a real shop? No business to keep him accountable, back up his work, provide him with proper tools and documentation to do the job, and provide him with honest and knowledgeable oversight to make sure he does his job well in general? I'm all for good mechanics going independent when they're ready, but he'* shown so many signs of poor practice, poor knowledge, and poor understanding of basics, that he shouldn't be allowed to fix a lawnmower, let alone a motor vehicle.

Do you have documentation that specifies that the bolts should be dry so I can show to him as that is perhaps the only way he will accept this.

When the engine is being driven, usually no or minimal coolant is lost. When the car is parked, that is when it looses coolant. I think diring the drive, the pressure in combustion chamber keeps too much coolant from entering, but after stopping for a while coolant starts to enter and fill the combustion chamber. I guess temp would have something to do with it.

He said that on another car he torqued the bolts a bit more and it stopped leaking so he tried this yesterday and will test today. I am frustrated asking him to not oil the bolts and I don't want to be rude to convince him of this.. I don't know why he insists this. maybe that is what he was told in college based on a particular type of engine.

If anyone has documentation that bolts should not be oiled would be helpful without offending him..He is a more mature person who appears to take pride in his work and client satisfaction... He is a good person so I have been patient but this has caused havoc for my family considering our work locations and shifts.

Thanks

You may find it'* OK for motor oil on the threads of the bolt but it'* very lightly brushed on so there'* no drips or such.
The Way it should be done without oil is the run the bolts in and out of their respective holes so they go easily.
This used to be the only way we did a head.

Sorry to butt in but these guys are EXPERT mechanics. You came here for their advice but then don't take it.
They have helped me numerous times in fixing my cars. They know what they are talking about.
I have been working on cars for over 40 years and have NEVER EVER heard of putting oil on head bolts. It'* just not done.
I don't mean to pile on, I wish you the best and hope you get your car fixed.

I got written instructions from local GM foreman and forwarded to the mechanic that the bolts need to be dry.. He said that oil was always recomended (he worked for GM) and that he doesn't know why they would have changed that. Looks like he oiled the bolts on 2 other engines that worked out fine.

I will admit it when I'm wrong, or maybe wrong, or don't know what I'm talking about!
I just googled "do you put oil on head bolts" and there are many debates as to pro or con on the issue. I had no idea!
But I will still defer to CC and carfixer007.

Service manual. The "mechanic" should have it. At this stage it doesn't matter anyways as he'* doing so many bad things together. It would be impossible to document a clear case to retrain this "mechanic" from the far side of the Internet when he already breaks things over and over and then has you buy more parts so he can break them again.

None should ever be lost. When that car was first built, it had 5 year/150,000 mile coolant and was expected to last at least that long with no consumption. The way he'* building it, this engine can't go 5 days/150 miles without losing a bunch of coolant.

Yup, when it cools from 100 degrees Celsius to 8 degrees Celsius etc. It loses some while driving as well, but only a little it seems.

That and while driving, heat expansion seals the head gasket a little better.

What car? A 1927 Ford Model A? Maybe a 1968 Chevy Impala? This can work in some cases, but not on your car.

Crossing fingers.

Factory service manual has the proper procedure. He seems easily offended while breaking your engine over and over.

I just watched four different YouTube videos of factory assembly of GM 2.4L engines. This part of the assembly goes like this:

1. Robot acquires assembled short block
2. Robot acquires a head gasket
3. Robot places head gasket on short block
4. Robot acquires an assembled head
5. Robot brushes the mating surface of the new head
6. Robot places head on head gasket
7. Robot inserts dry head bolts
8. Robot tightens head bolts

The only reputable place I've seen anything about lubricating threads in all of this searching is when you convert to ARP head studs. They ship the right lubricant for their studs with the kit, and instructions on how much to use etc. You are not converting to studs so this doesn't apply to you.

Appears to want to, maybe some of the time. The overall picture here tells me otherwise. If he took pride in his work, he wouldn't hand you back a car that hasn't been thoroughly repaired and tested.

Yes, you have been patient. About 127 times more patient than I would be with these shenanigans.

There is a part of me that thinks that maybe this rebuild going so very differently than his 30 years of other engine overhauls because he has the customer over his shoulder . . . but then I remember the terrible practices and procedures he is using (not just oiled head bolts) and I know that this isn't the cause.

Why would GM change anything without telling him? They should never innovate, just in case a situation like this might come up, right? LOL. Part of being a mechanic for a long period of time is keeping up on the practices and procedures for different generation of engines etc., and/or at least knowing to look for this kind of thing.