LR4 Low Compression

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dedbird

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I have had great luck with my 4 previous Land Rovers but looks like my luck has run out. 2013 LR4 has low compression in the #7 cylinder, 85psi, and a burned or stuck open valve. When the independent mechanic introduces smoke into the engine or cylinder it comes out the exhaust. Now the dilemma, what to do with this car? Cost to repair is about what it is worth. It has 112k on the clock and told it needs a new head. Probably worth nothing at this point. Any ideas?
 

Quijote

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Sorry to hear about this. I imagine these cars are actually worth quite a bit in parts. I'd investigate that possibility.

Out of curiosity, and because I think it will help all of us, what was the maintenance history of your LR4?
 

dedbird

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I like to think I take pretty good care of my cars. The mechanic I take it to is excellent. I bough it new and do regular oil changes. I had a check engine light on a month ago and had to take it to the local mechanic rather than taking it to Denver to the Land Rover indy. They said the error code showed it needed a tune up and put new plugs in it. Other than that it has been pretty solid.
 

mpinco

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........ It has 112k on the clock and told it needs a new head. ........

** does the mechanic know it needs a new head vs a rebuild? Or are 5.0 heads not rebuildable? Hmmmm .............
 

Keanan

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I hope I'm not too late to the discussion, it could be carbon buildup on the back of the valve. With direct injection carbon can build up on the back of the valves and eventually prevent the valves from closing all the way.
Pull the intake manifold and inspect the valves. It doesn't take very long and it's a good way to see what's going on in there.

Look up direct injection carbon buildup on youtube, with a walnut blasting it can be corrected.

If it's carbon buildup you can fix it easily for a few hundred dollars. If it's a burnt or bent valve then you will have to spend a bit more to get it fixed.
 

BeemerNut

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If it were my engine i'd remove the spark plug, enter the engine with an endoscope and look around the valve head for normal equal tan carbon color deposits around the perimeter of the exhaust valves. Also look for a overheated valve condition having a burnt white with possibly a slit from being torched and eroded away condition. If even tan you might have a chunk of carbon holding the valve open (fat chance!), possibly a warped valve. Check valve stem tip of having extra not wanted clearance, valve hanging open?
Investigation with a cheap ebay endoscope and laptop a quick easy and cheap DIY process. If you didn't drive the snot out of it or a lot of miles in this condition you didn't damage (torch) the valve seat possibly only requiring a light seat dressing plus replacing one bad valve. Add your (free labor) plus gaskets your up and running again and not too costly unless it's a high mileage about near death engine to begin with?
I would rather remove and replace ten pairs of 4.0 and 4.6 litre push rod engine heads than do another 5.0 litre engine AGAIN! Got suckered into replacing a pair of them on a LR4 a friend paid $750 for a LR4, a nice really clean looking low mileage LR4 with bad heads. Located two good used heads dirt cheap, new tyres, brakes including gaskets and fluids, he's into his LR4 at almost $1,800 total investment. A future wash when parting it out next expensive failure, a not if but when?
BTW, sure hope no anti freeze or burning oil were emitted out the exhaust possibly coating and destroying both those expensive Cats?.......~~=o&o>......
 
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gsxr

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I hope I'm not too late to the discussion, it could be carbon buildup on the back of the valve. With direct injection carbon can build up on the back of the valves and eventually prevent the valves from closing all the way.
Pull the intake manifold and inspect the valves. It doesn't take very long and it's a good way to see what's going on in there.

Look up direct injection carbon buildup on youtube, with a walnut blasting it can be corrected.

If it's carbon buildup you can fix it easily for a few hundred dollars. If it's a burnt or bent valve then you will have to spend a bit more to get it fixed.
All of the above is 100% correct.

It's a pretty likely to be a deposit preventing the valve from closing; not a failure of the engine / head / valve. Worst case it may require pulling the head to fix it, but there should be other ways to get it cleaned out. Note you can't inspect the exhaust valves by pulling the intake manifold. I'd consider trying some Italian tune-up first since that's free.

If you decide to sell... what color combo and how much do you want? ;)
 

MDJ2015

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I’ve got a 2012 LR4 also with low compression- in my #5 cylinder. Based on the difference between the wet and dry compression tests, we think it is the rings. Ive changed oil at half the recommended intervals so it wasn’t caused by that. I suspect it is a bad batch of rings.

Surprisingly, aside from a slightly rough idle the economy is unaffected and the power is not noticeably off. I continue to drive it. I am researching options to address it for the long run.
 

BeemerNut

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I'd remove the cam cover and check for excessive valve clearance by first rotating the engine at that bad valve's cam lobe placed on base circle first. Check for a broken valve spring.
Valve hanging open by a piece of carbon you should be able to thump the valve with a brass drift and hammer letting the spring tension slam the valve to seat crushing any carbon deposits. (If your lucky). If not carbon a hanging valve may have been hit by the piston, now you have a bent valve not seating properly. Last bad news a burnt valve looking like a narrow slice missing due to hot gases torching away the valve. An Endoscope is your best friend allowing a lookie inside unless you would rather strip the engine down removing the head. Get a factory service manual, take plenty of pictures, keeping all hardware nuts and bolts in tagged zip lock bags and parts layed out in big metal trays if it were my engine.
......~~=o&o>.......
 
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BeemerNut

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I’ve got a 2012 LR4 also with low compression- in my #5 cylinder. I suspect it is a bad batch of rings.

If it were a bad set of rings all other cylinders would have equally low compression.
......~~=o&o>.......
 
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