As I mentioned in another thread, I had to have my car towed to the dealer. Their mechanic determined that one of the valve seats had come loose. There was zero compression on that cylinder, and the seat, which is basically a steel ring that's pressed into the aluminum head, was bouncing up and down with the valve, preventing the valve from getting a good seal when it was closed.

The dealer wanted FOURTEEN THOUSAND DOLLARS just for the labor to do the repair. I decided to do it myself. I'm making videos as I disassemble the engine, and I'll hopefully be posting the first video in this thread later this evening. However, I wanted to go ahead and get started to show everyone what I've found so far. I expect this repair is going to take me a month or more. I'm super-busy at work and I can really only work on the car on weekends.

I removed the intercooler from the top of the supercharger, which allowed me to see the valves. The picture below shows the two intake valves on the #6 cylinder. The one on the right is the one with the dislodged seat. The valve is closed, but the seat is preventing the right valve from closing completely.

BUT... look at the one on the left. It is caked with carbon deposits. All of the valves are like that. That's what you get with a direct injection engine that also recirculates oily gasses from the crankcase back through the intake. There is no fuel to wash the oil off of the valves, and they get caked with carbon.

About a year ago I got a couple of cans of CRC intake valve cleaner for GDI engines. I drilled a tiny hole in the intake pipe right at the Y where it meets the throttle body. I put one can through the engine, and then a month or so later I did the other one. Looking at the valves as they are today, I don't know if it did any good at all.

 

I've always thought that to remove caked on carbon like that the valves would need soaking in the stuff, it's not going to work just flowing over the valve with the engine running.
Anyway, good luck with the rebuild Sam, looking forward to reading about it.

 

I believe the best way is walnut blasting . Common solution in the Audi world.

 

+1 on the walnut shell blasting. Machine shop will be able to clean the head and valves during the valve seat repair. I’m sure it’s not their first DI rodeo

 

Also normal maintenace in the DI BMW world. Every 40-50 kmiles.

Also, Sam, good luck with the repair. Any possibility that the carbon buildup contributed to the valve seat problem?

 

Might have missed it in your other thread, but how many miles on this engine?

 

It's hard to say. I doubt it, but I'm not an engineer.

Although now that I think about it, if the oil was able to seep into the microscopic crack between the aluminum head and the steel valve seat, I could see how it could gradually force the seat out as the carbon built up. And if you look at the seat in the picture I posted, you can see a thin ring of something dark on the seat. Maybe that's carbon buildup. Or maybe it's some sort of sealant they used to prevent oil from seeping into the microscopic crack.

 

105,000.

It has been my daily driver for the past two years.

 

Carbon buildup, while not pretty, does not look catastrophic. What oil do you use and what is your change interval?

 

So, how does that work then, could you describe the process please?

 

It's the same as sand blasting only using crushed walnut shells. You remove the intake and have to do it 1 cylinder at a time. Bring the cam up so both valves are closed. Then they walnut blast the head of that cylinder while also vacuuming it to contain the dust. It will clean the chamber like new. Then do the next cylinder the same way until all are done. Replace the intake and drive away. It's all labor.

 

This type of failure is not normal but does happen. Usually the cause is due to the valve "pounding" on the seat. That coupled with the heat cycle and the expansion/contraction of the 2 different materials tend to loosen the seat. As it gets lose the hole starts to distort and the seat falls out as yours did. The seats are pressed in using the heat cold method where the head is heated to expand and the seat are frozen to shrink them. Then they are pressed into the head. I would not be surprised that there are others starting to get loose. When you take it to a machine shop they can check but normal practice would be to replace them all after they verify that the head is rebuildable. Good luck and keep us posted. I had to do my XJS V12 heads back in the day . Thought it would be simple but ended up doing both heads .

 

OK, here's the first video of my engine repair saga. The video editing is turning out to be more difficult than working on the car, but at least my hands don't get dirty.

 

Yea, my garage is a mess. But I know where everything is. LOL

 

What's the secret for getting the supercharger off? The bolts are out. The belt is off. I can jiggle it and it moves slightly, but I can't lift it off the top of the engine.

 

It was way heavier than I thought it was going to be. I'm guessing that your air intake is already out of the way, but that and your coolant manifold are the obstacles. Service manual says it's a 2-person job, and that's how I remember it, too. (edit) I just realized you are in a 5.0 and I have a 4.2, so this may not be totally accurate for your 2010.

 

If it's a two person job I'm screwed because my wife is 5'2" and she weighs about 120 pounds. Between the two of us there is only one and a half of us.

 

If you haven't an extra set of hands, one of these might help.


https://www.harborfreight.com/1000-l...bar-96524.html

 

I was considering one of those engine hoists. The bar thing is interesting.

 

The bar is usually used while replacing engine mounts and such, and mostly holds the engine in place without lifting anything. In your situation I'd probably use a come-along attached at the ceiling. With sufficient support mechanisms in place, of course.