Head gaskets?

[Geoff Owens]

Just purchased a 2010 5.0 LR4
Codes:
P0300 random misfires
P0302 misfire cylinder2
P0304 misfire cylinder4
P0316 multiple misfires detected (1000rev)
P0354 coil circuit
P0100 MAF circuit
P0128 coolant thermostat
Plus a major oil leak.
My findings: swapping plugs and coil packs with the other side, clearing codes and starting produced the same codes. The oil leak is difficult to locate but is coming from the drivers side (bank 2) of engine. Thinking it’s either some oil line I can’t see or the oil cooler gasket leaking which is located under the intake. While running it smells sweet coming from exhaust. Pressure tested cooling system, pressure dropped maybe 2 psi but coolant level in bottle decreased by half . I’m leaning bad injectors which in turn failed head gasket on that side. But the ignition coil circuit code and the MAF code I haven’t completely diagnosed. The coil code stayed with the cylinder and didn’t follow the coil pack when swapped to the other side. I mean what’s the chance the wiring is bad or the the ECM? Or is it a result of the dead misfire on that cylinder? Maybe the MAF code has a part to play as well. But it could just be since the head gasket has failed and the injectors are bad it’s messing with the whole system therefore it’s throwing these other codes. This is a direct injection system and I used to be a master certified mechanic 10 years ago. But I’ve never done work on these systems or this engine platform. I have done my research and if I can 100% confirm the head gasket I’m purchasing the proper tools and parts from Atlantic British. Any thoughts folks? Has any one had gaskets fail? What’s the chances a head is cracked? How about the wiring or ECM having been the root cause? Or was it the Injectors which are a known issue? I appreciate your feedback and I’m just trying to get all my ducks in a row before I tackle this beast of a project. I’m completely confident in my ability to do it. I’m just looking for some more information before I order $5000 plus in parts and tools. Thanks

 

[jlglr4]

Those on the forum far more knowledgable than me will give you better advice, but from all my reading on these forums, the most common cause of a head gasket failure on the LR4 seems to be overheating. And that usually as the result of the plastic coolant crossover pipes bursting. If that’s what happened to your engine, then I’d guess there is a good chance the heads are warped.

I guess injector failure blows a head gasket by spitting a ton of liquid fuel into the cylinder - piston comes up and blows the gaskets? I just haven’t read of it in these cars. Plenty of people have had injectors fail, but haven’t heard of them taking out the head gaskets.

 

[Geoff Owens]

I think I’m going to at least tear down enough to locate the oil leak and replace the injectors and fully inspect the cooling system components. Probably change the plugs. I’m not 100% convinced it’s the head gasket. Probably still do full timing job.

 

[jlglr4]

If you’ve got coolant smell in the exhaust, not sure what else that could be other than a head gasket. And it sounds like you’re losing a lot of coolant - 1/2 the reservoir during pressure test. Seems like it would have to be burning it or it’d be spilling onto the ground at that rate. Did you check the compression yet?

As for the oil leak, the valve covers are known to leak oil on these as well, but not sure what kind of volume you’re seeing.

Anyway - sounds like an adventure. Good luck with it. Let us know how it goes.

 

[jlglr4]

One other thing - on the “other” lr4 forum, I had noticed this thread on a head gasket repair that might be useful to you. https://landroverforums.com/forum/lr4-38/2011-lr4-5-0-head-gasket-replacement-documentation-98876/

I’m sure there are threads on this forum as well, just can’t remember off the top of my

 

[Geoff Owens]

It has a coolant drip visible on the ground...but not the couple of fl oz missing from the reservoir. The cooling system was pressurized for 30 min. The oil leak was a constant drip ending mostly on top of the front differential driveshaft joint. Not sure if the smell wasn’t the unburned fuel.

 

[Geoff Owens]

I’ll keep this thread informed as I tear into it. I’ve seen that other “thread” and hope I don’t get that far and if I do I hope I don’t have compromised threads or worse yet a broken bolt....which I seen some dude extract on a tube video

 

[Michael Gain]

Oil leak is most likely your driver side valve cover gasket. There are no other oil lines above the front driveshaft.

I would recommend a compression test prior to tearing into the engine. It could save you a lot of unneeded work. Definitely verify what you are smelling from the exhaust.

Also, I would start with the MAF over the injectors (cheapest repair first). It may be reporting incorrect air flow, thus calling for more fuel to be injected into the driver side bank and causing the misfires. I am not saying that it is not the injectors (their replacement was the only thing that solved my misfire), but start small.

If moving the coil does not affect the code, I would be inclined to test the wiring. Check the connector first for debris and bent pins, and then follow the wire back through the loom.

Finally, if you are smelling unburned fuel, you will most likely have damage to the passenger side catalytic converter. Just something to keep an eye on.

 

[Michael Gain]

It has a coolant drip visible on the ground...but not the couple of fl oz missing from the reservoir. The cooling system was pressurized for 30 min. The oil leak was a constant drip ending mostly on top of the front differential driveshaft joint. Not sure if the smell wasn’t the unburned fuel.

Where exactly is the coolant landing on the ground? It will help us pinpoint where it is leaking on the engine.

 

[Geoff Owens]

Close to same spot as oil leak....drivers side close to the front side of engine....I bought an OE thermostat I plan on putting in also due to the code....
Compression test is a good next step....
Checking the wiring loom for cylinder 4 ignition coil and diagnosing the MAF are also on my top priority list. I have access to Alldata platform so I’ll follow the diagnostic procedures on those and get back to y’all. I’m gonna buy a tester to see if exhaust gas is present in the cooling system.