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Discussion Starter #1
The vehicle is a 2011 L322 full size with the NA 5.0 engine. It's got around 80k miles on the clock. I've got it all stripped down and the right head removed to replace the head gasket. I'm looking for some thoughts about what I should replace while it's all apart as it's many hours of work to get down to the basic engine long block to do this work. The source of the head gasket problem appears to have been water loss from leaks at the plastic water "manifolds" at the front and rear of the intake manifold. These water manifolds are both assembled of two plastic pieces that are solvent or heat welded together, and they both show signs of leaking at the joint, particularly the piece at the front of the engine. So these water distribution pieces are going to be replaced with new ones, and here are some of my other thoughts:
  • Replace the head gaskets on both heads, even though only the right head had the leak.
  • Replace the timing chain tensioners with the latest version upgraded tensioners, and replace the plastic ramps.
  • Put a new water pump and thermostat on it. Put all new water hoses on.
  • Have the injectors ultrasonically cleaned and install with new teflon seals.
  • New spark plugs.
  • Replace the heated oxygen sensor in the right exhaust manifold. The other O2 sensors look to be replaceable from the bottom.
What have I missed? (Thanks in advance!)
 

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2010-2012 Range Rover MkIII / L322
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You’ve come this far...I’d do both heads, including a valve job* if necessary. Use genuine JLR gaskets and ten new JLR head bolts per head. You’ll need to check whether you have 10mm or 11mm head bolts installed once you remove them.


On the direct injection (DI) systems carbon build up cannot be reduced with simple fuel system cleaning solvents etc as in indirect fuel injection systems (into the intake vs DI into the combustion chamber).

*There are services/devices that can “de-carbon valves” using walnut shell media.

Definitely have the injectors checked, cleaned and flow tested (before and after). Order new Teflon seals for the injector tips. Ensure the injectors are fully seated when you reinstall/seat them by gently tamping them down until you hear a solid metallic response to tapping on them with the injector removal tool’s slide hammer. No need to go all Thor on them, though. You’ll need to locate a vendor who’s set up to service DI injectors.

Replace the timing chain tensioners and guides. The chain will likely be just fine.

Replace the front plastic water channel, water pump and the plastic coolant channel bridging the rear of the heads.

Replace the coolant temp sensor in that rear “bridge” fitting. Far, far easier to replace it while it’s all apart ;)

CAUTION: when you re-connect the rear temp sensor make sure you don’t inadvertently swap that connector with the intake flap position connector on the rear surface of the intake manifold. The plugs look alike except one’s gray and the other’s black plastic.

Replace the thermostat and serpentine belts - the cooling fan belt is a stretch belt.

Once you remove the cam(s) MAKE SURE you keep the cam buckets in order of removal so they can be reinstalled on their original valve’s placement.

It’s also worth creating a grid (simple spreadsheet) and writing down the etched number inside each bucket to its corresponding cylinder/valve. When you put it all back together and check the initial valve clearance you’ll already know what size shimmed bucket you’re working with if you need to make any “adjustments” by substituting a different (thicker or thinner) shimmed bucket.

If you do go ahead and refresh the timing chain area DON’T FORGET to reinstall the upper half of the engine’s oil pan vacuum drain tube once you’ve set the valve timing.

That’ll keep you busy for now:)

Rob
 

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My only addition would be the cam sprockets. It's a hard choice because the sprockets alone will bump your budget drastically. However, if there's a time to do them...it's now that you have it all pulled apart. Pix and your feedback is very much welcome after you put everything back together!

It looks like more and more folks with the 5.0L are doing their own work. The more info we have the better.... especially for folks like me who are yet to do the job :). Best of luck!
 
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I've been told that those coolant pipes have been now upgraded to a one piece design as opposed to the two halves welded together. Make sure you get the upgraded one
 

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I've been told that those coolant pipes have been now upgraded to a one piece design as opposed to the two halves welded together. Make sure you get the upgraded one
Yeah they sure have. The original design on MY10s were aluminum but 2 pieces with a joint midway (not that kind of joint!). Then they went composite with a joint and now they're 1 piece, so to speak.

OP I second the "Do all your cooling pipes and hoses" while you're in there. The JLR manual says every 60k miles or 7 years whichever comes first. Either way, most will break when you try to remove them so you end up replacing them anyway.
 
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On the NA 5.0 it's not a 2 part coolant pipe and has not seen any updates yet. The the S/C that has the upper and lower pipes.
The only thing I would add is to change out the plastic coolant pipes to your list.

If you need any further information I did a series with a youtuber Samcrac, where he bought a range rover 5.0 that needed a head job. So there's a ton of info in that video series and also torque specs and instructions and things to watch out for while doing the job.
 

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On the NA 5.0 it's not a 2 part coolant pipe and has not seen any updates yet. The the S/C that has the upper and lower pipes.
The only thing I would add is to change out the plastic coolant pipes to your list.

If you need any further information I did a series with a youtuber Samcrac, where he bought a range rover 5.0 that needed a head job. So there's a ton of info in that video series and also torque specs and instructions and things to watch out for while doing the job.
Did he ever get that thing running? Last vid I saw he said the timing was still off and needed to do the whole thing over again (something to that extent).
 

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Did he ever get that thing running? Last vid I saw he said the timing was still off and needed to do the whole thing over again (something to that extent).
It's in my garage now. And yes it runs. But if I say more I spoil the next video on it.
 

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Discussion Starter #9
Thank you all for your helpful responses, I have ordered all new coolant pipes and hoses and they are crazy expensive, but this is the time to do it. The plastic piece that directs water from the front of the "valley" on either side to the thermostat is what I believe caused my problems. The seam in this piece has split open for quite a distance and I can actually see where hot steam sprayed onto the bottom of the intake manifold! The plastic water pipe that bolts to each head in the rear also was made of two pieces that were "welded" together and it was also starting to leak, so a new one has been ordered as well. I am still considering whether to replace the variable timing sprockets. I wish there was a sure-fire way to assess them. This rig has less than 80k miles on it, so normally I would expect chain-driven timing parts to be just fine, but maybe not?.
 

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That's a pretty common point of failure on these 5.0 NA motors (as fitted to both Jag and LR vehicles) - even worse is that when a car has a serious overheat the plastic can begin to degrade and shed. Once any plastic suspended within the cooling system cools again it can lodge within the internal block/head cooling channels. Once that occurs the engine will have incurable overheating issues due to blocked/partially blocked waterways :(

It's worth replacing the front and rear plastic water channels whenever you have to remove them as a step process during another repair [as in your case for removing the head(s)] even if they appear be OK. Less expensive to replace them while they're off than have to replace a cooked motor.

Put a little silicon grease on the o-rings when you insert/push in the two water connections to the block. Don't over tighten the two torx bolts. Replace the o-rings on the oil cooler's coolant channel too. Some folks just replace the small plastic pipe there but so long as you have new o-rings it should be just fine.

Rob
 

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Discussion Starter #12
Again, Rob, thanks for the sage advice. WrenchMonger, I'll look for the videos. Although the Rover project is taking my time, attention and money away from a couple of other projects that I really want to get going on, I also want to take my time to get it right. I haven't done any serious work on this engine before, so the help and tips from people who have done it before is a huge help.
 

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Update. I removed the left head along with the right. I found a terrible mess in the left side combustion chambers from coolant getting in, but after some cleaning, the cylinders and pistons crowns look okay. BUT, bad news! I checked both heads with a straight edge and both are quite warped (.015" to .020"). And, worse yet, when I put the cams in and torque the bolts, they are all bound up as one would expect with heads warped that much. At first check with my aluminum straightedge, the block deck doesn't appear to be warped on either side, but I have ordered a new Starrett machinist's straight edge to give it a really close examination. In any event, the heads have to either be straightened or replaced. If I find a reputable shop to straighten the heads, I may go that way, as it may be difficult to find good used heads for this engine. If you have thoughts on this, I'd love to hear them!
 

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On other aluminium headed motors which have warped, whenever I’ve had the choice of simple skimming or having the machine shop carry out an intensive heat up and “press” the head against the warp prior to being skimmed method, I’ve favoured the latter. Thus far I’ve had very good luck.

One particular warped head on a Honda I rebuilt at around 60,000 miles many years ago was “repaired” using the press method and it still runs just fine with now over 180,000 miles on the odometer.

The secondary advantage of the more involved heat application/press process is that the cam journals will also require less machining back towards their correct alignment.

You might want to call around the machine shops in your local area to inquire whether they offer such a service.

I used a machine shop in the Ft Worth area, fwiw.

Rob
 

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Discussion Starter #15
I agree. I did some searching yesterday and think I've located a shop in the Phoenix area (not too far away from me) that does the "straightening". All four cams can't be turned when they are replaced in the heads, so a simple resurfacing of the head won't do. I'll report back when I've contacted them.
 

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Wow, I've never heard of this technice. It's called "straightening?" I was only aware of milling the heads straight (and block if necessary).
 

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Yes, It's pretty amazing. The head is bolted a massive surface plate and then put in an oven and heated up to pull it back to shape. When the heads are warped as much as mine are, it's really the only option other than replacement.
 

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Well, this morning I drove to Phoenix and visited the shop that offers head straightening for aluminum heads. The bad news is after considerable investigation, the shop foreman determined that my heads were not good candidates for their head straightening process. For one thing, the amount of warpage on the top of the head, as measured on the valve cover sealing areas, the flat machined area where the injectors go and across the camshaft journals, was noticeably less than on the combustion chamber side of the head. This indicated that the heads didn't bend uniformly and the shop guy said that it could result in internal cracking when straightened. He mentioned that they had cracking problems with a couple of other late model DOHC Ford heads that they tried to straighten, and they didn't measure as bad as mine when they came in to the shop. So, it looks as though I'm shopping for either used heads or a used engine. So far, all I've found are entire used engines. And, frankly, they scare me knowing what I now know about the problems that can occur from overheating.
 

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Well, $2,133 is a whole lot of money, but actually a better deal than $1,950 each for used heads, which I was quoted by one Rover dismantler. They didn't have a pair anyway, so the point is moot. I've decided to go ahead and remove the rest of the engine and put it on the engine stand. That way I can assess the bottom end and make sure that it is in good shape. If I use the original engine, it needs to be dismantled anyway so the block can be milled about .008" on each bank to make it totally flat again to properly mate with new or reconditioned heads. But, if the crank has any scoring or the cylinders are out of round, I'm not going to go any further with this engine and just start a concerted search to find a used engine in good condition.
 
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