Crushing at 225kph on the autobahn sustained for 20 minutes and I lost compression in a cylinder, instantly I thought it was the head gasket when we pulled over, google said you can run on three just keep it low in the revs, the oil was good no mixing, no overheating but we still had a while driving to get back to Prague from Munich where it blew but get back we did.

I lifted the head and dropped to the machine shop for a skim, on first inspection they said I had blown a piston due to the aluminium residue on cylinder 1 valves. So I dropped the pan today and pushed out the piston but looks identical to the secondhand replacement that arrived today.

So I’m just trying to understand where this residue came from and if it’s safe to put back together? The plug was missing 4mm off the anode but this is too little material to account for the residue on the valves + plug aren’t aluminium.

It’s on 151km/100,000 miles so doing a big service to hopefully stop what ever happened,Spark plugs

Injector service

Belt

Chain tensioner + bolt

Piston + rings + rod bolts

Cylinder hone

Head gasket + sprocket bolt + head bolts

Cam cover gasket + bolts & o rings

Head skim + valve stem seals

Oil pan gasket

Dipstick o ring

Oil pressure sensor

Water temperature sensor

Airflow sensor

Inlet sensor

Cam position sensor

Crank position sensor

Fan relay circuit

Thermostat
Finally, the top speed should be 222kph and we had 225, and my foot wasn’t quite down! So a tune or tailwind or a mix of faulty sensors eventually blowing my head gasket!?

Also on the 1500km trip I topped up 2l of extra oil:/

I’ll do a compression test on Saturday to see if all is well but the metal residue is a mystery!?

Any advice would be greatly appreciate I’m a chef and the last head gasket I did was on my r5 gt turbo 20 years ago! Cheers