2016 LR4 Coolant Crossover, Water Pump, Thermostat Replacement

jlglr4

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Thought I’d share (yet another) report on the coolant crossover issue. I have a 2016 Landmark Edition (service date was April 2016 I believe) with just over 50K miles. Took it to the dealer three times (two different dealers) prior to warranty expiration for coolant odor, but no leaks were found on the pressure test. The head mechanic at one dealer admitted the coolant smell, but couldn’t find any leak and there was no significant coolant loss, so they wouldn’t do anything more.

With the shelter-in-place going on, I decided to replace the coolant crossovers (front and rear), water pump, and thermostat, both as a preventative measure and to see if I could locate the source of the coolant smell. Also replaced the supercharger isolator (which was starting to rattle a bit) since I had it off (separate post).

With the supercharger off, I didn’t find any leak in the valley or on the back of the motor - no coolant anywhere, dried or wet. But the “Y” shaped pipe of the front crossover that goes under the supercharger was just barely holding on. The pipe has its ends buried in the block with some o-rings. The pipe had degraded in the channel that retains the o-rings, so that the pipe lifted off the block leaving the o-rings and pipe ends in the block. See attached pics. The pipe was simply eaten away above the o-rings with just a tiny lip left in the block. Once that lip is gone, the coolant would have come spilling out. This is at 50,100 miles, and I’d been smelling coolant since about 45K miles.

I’ve read similar reports on these forums, and at similar mileage from my recollection. So it seems that by 50K or so, these cross-over pipes become a liability.

I didn’t see any leaks or other problems around the rear coolant crossover, nor around water pump or thermostat. But I replaced all these items as a preventative measure. Everything went back together and I haven’t noticed the coolant odor after driving it for about 1000 miles or so, including a couple longer road trips. I can only guess some vapor was escaping from the front crossover.

A parts list is included below. I’m certainly no expert mechanic, but if anyone is thinking about DIY’ing this like I did and has any questions about the procedure, happy to give any help I can. I started trying to record a video with the intention of posting it, but failed miserably. However, there are several posts over at the Jaguar forum on supercharger removal that were helpful.

Parts List
LR090630 - Redesigned “water manifold” part of front crossover
LR092992 - Redesigned “water pipe” (Y-pipe) part of front crossover that goes into the block
LR109401 - Manifold - Heater (Rear crossover pipe)
LR097165 - Water pump assembly
LR028136 - Oil cooler tube (goes on the back of water pump)
LR095895 - Thermostat Kit

Other parts if you want to replace more hoses connected to t-stat/crossover, belts
LR050855.- Lower radiator hose (includes T-stat to hose adapter and coolant temp sensor)
LR033994 - Outlet tube
LR049990 - Inlet tube
LR071040 - Supercharger drive belt (note - there appear to be two sizes with different lengths - make sure you get the correct size for your model year)
LR051263 - Serpentine belt
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Michael Gain

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Yep. Mine looked the same. Good catch! What method did you use to get the supercharger off? I saw a couple in the jag forums, but would like to know what worked best for you.
 

TrinidadLR4

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Yeah, the necks are a problem. Often though, it starts leaking through the seam that separates the top and bottom halves of the y pipe. Apparently there is newer design that is one piece and supposed to be better. Either way, it's a 50-60k routine maintenance item.
 
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jlglr4

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Michael - the charge air cooler needed just a very gentle pry to pop off. The supercharger itself was on pretty good due to two dowel pins that the folks on the jag forums described - glad I knew about those ahead of time. I just started wiggling it up and down (see-saw motion) from the snout until I got it moving, then a gentle pry up from underneath. Can’t remember now whether I used the pry bar or put a little block under the front edge of the charger and pressed down to get it levered up off those dowels. I think I tried both but can’t remember which worked.

I won’t say my method was the best. The dowel pegs sit right next to the knock sensors on the block (which I did not know at the time). When it popped free, that dowel peg just barely bumped the knock sensor and cracked the housing on the electrical connection. Easy fix, but if it jumped the wrong direction, it could have done some damage to the knock sensor. If I had to do it again, I might buy one of those engine support bars they showed on the Jag forums, or maybe just rigged up something similar on my own. It doesn’t require a lot of force, but rather a straight-up pulling force, which is difficult to do when you’re bent over the engine.

The other thing that helped was using guide pins for reassembly to get the supercharger back in while keeping the manifold gasket in place. Land Rover charges around $100 for the pins, but I made guide pins by cutting the heads off 8mmx1.25/80mm partially threaded bolts from home depot and grinding them smooth. Worked great.

Overall, not too difficult. Working at the back of the charger to get to the connections and get that rear crossover replaced was probably the toughest part.
 

Michael Gain

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Great insight, and thank you for the quick response. The knock sensors were never mentioned in the jag forums. So, I'm happy you brought it up here. I was also thinking about the metal bar setup, but it seems like you had success without. I too am just trying to get better access to the rear of the sc to replace the rear crossover.

Thanks again!

Michael - the charge air cooler needed just a very gentle pry to pop off.
Overall, not too difficult. Working at the back of the charger to get to the connections and get that rear crossover replaced was probably the toughest part.
 

jlglr4

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I regret that I my attempt at a video on the repair was thwarted (it shut off early in the process and I hadn’t noticed). But, in case anyone is looking for pics, this thread in the jag forums has some great shots. Even shows the knock sensors I mentioned (though I hadn’t noticed this before I removed mine).

https://www.jaguarforums.com/forum/xj-x351-53/supercharger-removal-188511/
 

Frank8

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I thought the coolant pipe was a V8 problem.
Does the six have the same issues?
 

jlglr4

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Absolutely. There have been many reports on the forums, and at least one person on this forum (maybe a couple now - can’t recall) lost their SCV6 engine due to this problem. The time from coolant loss to overheating is apparently very short. Not sure if the supercharged V6 might even be more susceptible to overheating than the V8.
 

ScottK

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Just had to replace the rear coolant manifold on my 16 SCV6 with 87K on it. Caught it just in time.

I'm no mechanic so can I assume that the "rear coolant manifold" my shop noted is in fact the rear crossover pipe? they do mostly Porsche and BMW work. But I have limited resources due to the fact that I live in the Detroit area.
 

jlglr4

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Hey ScottK - I know the area well - grew up in West Bloomfield. In the SF area now, but still have family out there.

I think its a good assumption they changed the rear crossover. The part is actually called the “heater manifold” - its the coolant leaving the block hot and distributed to the heater core. So that seems to fit. Can’t imagine what else they would have replaced that would fit that description. But, you could call them and ask for the part number they ordered and check it against the list above (or just repost it here). No one else makes the part (that I know of), so it had to be from land rover.

Gotta say though - do the front crossover as well if it hasn’t been done yet. Its a PITA because you need to pull the supercharger, but its a real liability.
 

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