My latest project. Mack comes in with Low to no oil pressure, then its suspected high compression on one cylinder and no start now. Long story short and 5 hours of diag labor later, I get the cylinder head off.

One exhaust valve is broken and the intake valve is skewed. All the dings in the head is caused by the broken valve bouncing around.


If you look here, you can see where the piece of valve punctured the cylinder head. It actually put a small hole in the water jacket.



One the cylinder filled with coolant, it hydrolocked the engine and caused the #6 cylinder to crack the liner. I'll have pictures of those once we get approval to do the work.

Right now, the parts lists consist of:
Cylinder head
Piston/liner kit
Turbo
EGR cooler
Oil pump
OIl filter housing
Oil cooler
Injectors

All because a little valve broke.

Total estimate, $32,000 parts/labor.

Just seen a note in our Asist system, quote for in-frame engine rebuild. Total is at $40,000 right now.

Ouch...

Wow, it'* amazing that there weren't more punctures. Not much room in there at TDC.

What kind of engine?

Any idea what caused the valve to fracture in the first place?

I figured there would be more damage to the piston too.

This is a Mack MP8 13L diesel engine. In a Volvo truck, its the same engine, but its designation is the D13. These engines are used mostly in highway Mack and Volvo trucks. Macks use them a lot in the vocational/municipal industries.

As far as the valve goes, this unfortunately happens often.

#6 injector was changed out recently, only thing I can deduce at, is when they change the injector, a lot of coolant and fuel fell into the cylinder and they didn't suck the cylinder out. Maybe a partial hydro-lock caused a hairline crack in the valve. Who knows.

That makes sense. I wouldn't have thought of that.

Wow, ouch is right. How many miles on that one?

2016- 170,000 miles

They opted for a premium Mack rebuild, which comes with a 2 year, unlimited miles warranty on the engine.

So at the rate they're going 85,000 miles. That'* a cool warranty!

Kept forgetting I took pics once I got the piston out. Here is a new one sitting next to the one that got destroyed. I tried to take pics of the cracks in the liner, but they didn't turn out well.