Rear Crossover (Heater Manifold) failure mode?

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Lgibson

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That high point seems perfect for bleeding air out. I was thinking one might also be able to refill the manifold from there as well.
 

greiswig

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I would be sure to use all 4 of the bleed ports. If you only use the highest one, you risk missing a pocket of air in one of the other loops. They put in more than one for a reason.
 

blake aiken

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I would be sure to use all 4 of the bleed ports. If you only use the highest one, you risk missing a pocket of air in one of the other loops. They put in more than one for a reason.
Where are the other two? I’ve only seen the reservoir and heater core ones.
 

jlglr4

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Again - might be different on the V8, but on the V6, there are indeed 4 bleeders: (1) reservoir, (2) front crossover (plug rather than screw-type), (3) passenger side towards back of the engine, (4) hose leaving upper radiator on the drivers side.
 

Stuart Barnes

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Just changed my rear crossover, heater manifold, and it was in as new condition after 67k miles on a 2015 scv6.

The front however was a different story, my knuckles definitely jumped on a grenade for the engine :)
 

Justin Mann

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Working on the front and rear crossover replacement now. Front was definitely the issue for me. Back looks fine but I'm going to replace it as long as I can reach the screws with a flexible extension(yet to ship). Not too worried about any issues bleeding the air out of the system. Noticed when I removed the intake someone never replaced the gaskets so I'm waiting on those to ship also. Noticed also their seemed to be a slight mist of oil in the intake.
 

greiswig

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Oil in the intake seems to be pretty normal, and given the PCV issues caused in some other vehicles, it actually seemed pretty light to me on my 47k engine.
 

Stuart Barnes

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Oil in the intake seems to be pretty normal, and given the PCV issues caused in some other vehicles, it actually seemed pretty light to me on my 47k engine.


I found it much easier to use a set of these

6D088D7B-CB0F-4C7B-86F3-C3F239D4BDD9.jpeg

You’ll curse that the lower bolts have to come out a couple of degrees at a time. But it was easier than using extension bars and u joints for me.
 

timc930

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The front however was a different story, my knuckles definitely jumped on a grenade for the engine :)

If you are talking about it coming apart at the ends, that is normal for composite cooling pipes (at least on BMW's) as every coolant pipe that I've replaced on all of the M54 engines that I've worked on came apart when I pulled them out of the block and they were not leaking prior to being replaced. Now, having said that, I have not (yet) replaced the coolant pipes on my wife's LR4, I have all of the parts, just have not had time.

I too have a very small (several ounces a year) leak in my my rear pipe, that's been "weeping" coolant for the past two years. I am taking the car to Boston next week (fingers crossed) and will replace everything when I get back.
 

Stuart Barnes

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If you are talking about it coming apart at the ends, that is normal for composite cooling pipes (at least on BMW's) as every coolant pipe that I've replaced on all of the M54 engines that I've worked on came apart when I pulled them out of the block and they were not leaking prior to being replaced. Now, having said that, I have not (yet) replaced the coolant pipes on my wife's LR4, I have all of the parts, just have not had time.

I too have a very small (several ounces a year) leak in my my rear pipe, that's been "weeping" coolant for the past two years. I am taking the car to Boston next week (fingers crossed) and will replace everything when I get back.


The front pipe where it enters the block was totally degraded. The only sealing was from the pressure of the upper pipe and the 2 securing bolts and the crusted coolant mix. The o rings had totally deformed and started to degrade with respects to their compressibility aka squishiness.

The rear manifold/crossover pipe was in a visually good state apart from the sealing o rings which were again degraded but not as much as the front pipe, oh and by the end there was a convincing smear of the red stuff to show it out up a fight.

The surprise item was the small capillary hose from the water pump. This was quite eroded, or batteries from the coolant pump job last done by Santa Monica Land Rover, who knows, but it’s replaced now so all good.

All this on a 2015 with 67k probably mostly city driving in la. So it’s been cooking for quite a time.
 

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