Probably head gasket leak - tough questions

[kamyk155]

Hi guys. I'm driving my car from last oil/filter year service in may with somekind of oil leak.
Hyundai service said it is small leak probably from head gasket. They cleaned it and after three weeks I returned to them and leak is still there.
After that I checked it again in my friends workshop and he found this leak again - he said it is head gasket....
Here is the low quality picture from inspection camera:

This leak location is.....if you go under the car, remove engine plastic undertray, then looking towards the front of the car - side of the engine from driver and pasenger seats.
For now I'm driving like that and I'm checking oil and coolant every time.
What is weird - no problems with power, oil level still good, coolant level still good, no weird engine sounds or feeling.
Oil and coolant have good color, oil cap is clear, no traces of mixing. No weird exhaust smoke. Temperatures of oil and coolant are ok (OBD screen).
Because leak is a leak I need to repair it. I waited from may to collect some cash and maybe reinforce the whole engine (pistons, rods, gasket, studs and so on) but I can't found a proper workshops so for now I want to do only gasket and maybe stronger studs.

Quick reminder - my car is 400BHP, about 500Nm and max 1,62bar boost.
So here are my tough questions:
1- what kind of head gasket ? Athena (cut rings) / Cosmetic MLX / OEM - other ?
2 - ARP studs - normal black or CA625+

Some shops offer a choice of thickness - I saw Athena 0,81mm - 1mm and 1,12mm. In most shops 1mm.
Cosmetic is typical 1mm but I saw other thickness too in other shops. OEM is 1mm.
Next thing is bore size. I don't know that until engine will be opened....most gaskets are 87mm.

For now I don't like athena cut ring - I read that those rings cut into the head of the engine.....soooo if you do it wrong or need to replace gasket in the future again you need to deeper head resurfacing next time.

For now I have problem with choice of gasket - thickness, bore size and which one.
Or maybe new OEM gasket plus ARP studs will be enough ?

 

[p_b82]

No experience of the i30N engine, but on a previous diesel car I had been getting headlift (the TLDR version hybrid turbo was too small on the exhaust side and generating so much back pressure the gasket was failing exhaust gas -> waterway => boiling coolant when giving it the beans).

I tried just ARP's to solve the issue and it held for longer but it did eventually also fail - we hadn't worked out the root cause so hoped the studs would do the job.
We considered wire-ringing the block, but there wasn't enough clearances for us to be confident that wouldn't cause another problem.
the gasket was a standard MLS type (different thickness options depending on original build tolerances 1-3 "hole").

Not sure how much diagnostic / troubleshooting you're able to do as part of the replacement process - but if you can see the nature of the failure it might be easier to decide on how to look at solving it - if it's a minute failure in one place, Studs/bolts with a little extra clamping pressure may well be all you need. (the first failure we got some standard bolts and gave an extra tiny part rotation on doing it up)
If it's failing in multiple places then you might need to be more drastic.

Personally I'd steer away from deviating from the standard gasket style initially - so that if the bolt/stud solution doesn't work, you don't have a more troublesome repair - EG rings forcing a head/block skim etc.

One thing the mechanic that was working on my car did say to me at the time - if the headgasket remains the weakest link, then at least you can spot the problem before it causes something else more serious to fail