The 75 and ZT Owners Club Forums - View Single Post - KV6 coolant bleeding

StewartIngram · 29th November 2021, 15:47

Lets start with a few "I know's...."

I know we have plenty of threads on KV6 bleeding
I know R75 & KV6 pretty well (since 2008)
I know of the official Rover method & have used it a number of times, (BUT... see later)
I know of the vacuum fill method & have used it a number of times (another BUT...)
I know of the correct level mark on the header tank.
I know how to successfully bleed a central heating system (Is that relevant you ask - wait & see!
I also know that I learn something every day! Regardless of all the above, I am not a Know-All.....

This problem really started with the heater going cold on the passenger side, a couple of weeks ago; I decided to buy a new matrix, knowing that I would be starting with a known good one, rather than cleaning the old one & refitting it, with the possibility of it not being fully cleaned. However, there is a possibility of a precursor to all this in that I have been regularly topping up for ages. Not a large amount but I keep an eye on it. I have checked around, and found trace of a leak from the front inlet manifold, so will be changing the gasket there in the near future.
However, I am wondering if anyone has ever modified the system to make bleeding easier? I'm interested, because my system is modified, as I have installed lpg, and the hoses have been extended to a vapouriser for the lpg, which puts the highest point of the system higher than normal. This in turn makes the Rover method just about impossible, as the header tank cammot be raised quite enough.
I've now changed the heater matrix, with all that entails with the clips - I had to modify one with hose and jubilee clips , as expected. I've since had trouble bleeding it. My Pela vacuum pump refuses to create enough vacuum to collapse the top hose - though it has previously managed. So I may have a fault with that - or something else in the system.
I've tried the Rover method - can't get rid of the air (I assume) as it is still cold. In desperation, I've tried the Rover system again, then removed the hose from the vapouriser and slowly poured (plenty of) water into the hose. This has given me some heat, though I feel it should be hotter. The hose is actually one from the heater (not sure whether In/Out) which goes back to the heater hose after the vapouriser (so basically extends that hose). It was working before - I managed to bleed it when I fitted lpg, and it is identical to the previous car, which I also converted and bled ok. Even back then, I wondered if a mod to give a better bleed valve position could be done. In fact I recall someone's pic with a tall vertical pipe at the back of the engine somewhere. No idea of components needed (if it can be done), but I'm sure that c/h valves etc could be adapted.

29th November 2021, 15:47	#1
StewartIngram Gets stuck in Rover 75 Connoisseur 2.5 V6 auto Join Date: Jan 2008 Location: Chatteris, Cambridgeshire Posts: 906 Thanks: 320 Thanked 159 Times in 127 Posts	KV6 coolant bleeding - modifications? Lets start with a few "I know's...." I know we have plenty of threads on KV6 bleeding I know R75 & KV6 pretty well (since 2008) I know of the official Rover method & have used it a number of times, (BUT... see later) I know of the vacuum fill method & have used it a number of times (another BUT...) I know of the correct level mark on the header tank. I know how to successfully bleed a central heating system (Is that relevant you ask - wait & see! I also know that I learn something every day! Regardless of all the above, I am not a Know-All..... This problem really started with the heater going cold on the passenger side, a couple of weeks ago; I decided to buy a new matrix, knowing that I would be starting with a known good one, rather than cleaning the old one & refitting it, with the possibility of it not being fully cleaned. However, there is a possibility of a precursor to all this in that I have been regularly topping up for ages. Not a large amount but I keep an eye on it. I have checked around, and found trace of a leak from the front inlet manifold, so will be changing the gasket there in the near future. However, I am wondering if anyone has ever modified the system to make bleeding easier? I'm interested, because my system is modified, as I have installed lpg, and the hoses have been extended to a vapouriser for the lpg, which puts the highest point of the system higher than normal. This in turn makes the Rover method just about impossible, as the header tank cammot be raised quite enough. I've now changed the heater matrix, with all that entails with the clips - I had to modify one with hose and jubilee clips , as expected. I've since had trouble bleeding it. My Pela vacuum pump refuses to create enough vacuum to collapse the top hose - though it has previously managed. So I may have a fault with that - or something else in the system. I've tried the Rover method - can't get rid of the air (I assume) as it is still cold. In desperation, I've tried the Rover system again, then removed the hose from the vapouriser and slowly poured (plenty of) water into the hose. This has given me some heat, though I feel it should be hotter. The hose is actually one from the heater (not sure whether In/Out) which goes back to the heater hose after the vapouriser (so basically extends that hose). It was working before - I managed to bleed it when I fitted lpg, and it is identical to the previous car, which I also converted and bled ok. Even back then, I wondered if a mod to give a better bleed valve position could be done. In fact I recall someone's pic with a tall vertical pipe at the back of the engine somewhere. No idea of components needed (if it can be done), but I'm sure that c/h valves etc could be adapted.