History of overheating, do I have a bad head gasket now?

Replacing head gasket and ignoring cleaning of the EGR system (and intake mainifold) might well be why the replacement gaskets are promptly blowing.

Just my 2 cents: the clogged EGR is the cause of head gasket failures: miles pile on, EGR clogs, head gasket blows. And almost invariably it fails at cyl 1 or 2, which is the end of the intake manifold whose EGR passages clog first.

 

Are you thinking to replace head gasket yourself, have mechanic do Exhaust Gas Recirculation cleaning? If so, I’d be inclined to do the opposite: the head gasket replacement is a big job, and egr cleaning relatively easy, but time con$uming. More info on the latter in my signature.

 

Do both, a lot of money NOT spent....

 

Easy, since there’s no budget constraint mentioned, not a diy’er and no alternative travel work around listed, just sell the car as a project and buy an entirely new 2021 prime. No down time to anything and will last for many years.

 

Yeah... that would definitely explain what the mechanic had a problem with in previous efforts and probably offering that info to 'em will make them more willing to do another head gasket the right way this time!

 

In terms of a long term plan for regular maintenance of the EGR, you could but a new EGR and have the mechanic install that and then keep your old EGR and clean it yourself and then when it's time have your mechanic swap EGRs again. I know some mechanics don't like cleaning stuff and over-charge for that kind of work.

 

Bent piston rod is possible and can mostly be checked by putting each piston at top dead center with head off and making sure pistons are in exact same spot on all four of them.

 

EGR “replacement” is overkill, typically. Unless it’s a hopeless lump of carbon. And just moderately difficult DIY. More info in my signature.

 

Pressure washer gets the job done.

Of the dozen I have done, the pressure washer has gotten them all clean every time.

And there have been some seriously clogged coolers.

Something to consider .

 

Does it mess up the coolant system for sure? My idiot mechanic didn't ask me, he just put some block sealant in my cooling system.

 

Never a better time for locking up your car than when a shop mechanic is around.

 

With at least one of the sealants, a 50/50 mix of water and (regular household white) vinegar will dissolve the goop. If you can extract some coolant, get some with evidence of goop, you could test it with this mix.

 

He did something you didn't approve, and it can cause damage ot other parts.

 

Depends what he used and how much he used. Old school sealer only works with a flushed system filled with distilled water and flushed again after a period of time. Both flushes requires multiple passes and several hours of time before adding the approved antifreeze concentrate. These are pretty safe but most mechanics and owners go for the easier antifreeze "compatible" sealer and just leave it in. Sometimes adding two or three times the sealer when it does not work. Those guys plug heaters, pumps, thermostats and or radiators.

No matter what type, the sealers all fail in a few weeks to a few months. Just enough run time for scammed owners to report good results and help sell more. Flush it out. Several times.