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Dear All,
Not so much oily as odd. I've noticed for a long long time that the heating air gets noticeably hotter when going round right hand turns and cooler to the left. i'd imagined this was some sort of surge in the cooling system but all my levels are up, no leaks and "burped" free of air, that i know of.
Has anyone else observed this, anyone got an explanation?

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I'd wonder if you have a flap in the cooling system not working how it should? Can't see much chance of fluid levels being affected by turning the car, but a loose flap maybe?

No dreaded cheque book symbol is there?

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Looking at post 554 here https://rangerovers.pub/topic/1620?page=28, yes there is.......

I've actually heard of someone else mentioning this problem in the past but no idea if he ever found the cause.

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Well spotted. Well first thing would be to see why thats on with Nano or similar diagnostics then?

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So, are you positive the temperature of the air coming from the vents changes?
If so.....That's a good one!
If not, it is just possible that you are experiencing a bit of fluid dynamics.
If you have for instance a large Gin & Tonic, with ice.....and you rotate the glass, you would note that the ice and liquid
lag behind the container.
The same thing happens to the air mass inside a vehicle. If there is a warm pocket and a cold pocket, when you turn, the air will shift at a different rate than the container...in this case, a P-38.
I have not noted this on mine, however, in my large Ford work van in Hawaii, it was very noticeable as the smaller
air mass up front was cool, and the large air mass in the back was warm and humid. Turn either way, and things would be warmer or cooler.....
Try the experiment I mentioned. If it does not seem to work, drink that one, and make a bigger G&T.
Repeat till it works, or you forget what you were trying to prove!
Cheers,
Tom

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Bolt wrote:

Try the experiment I mentioned. If it does not seem to work, drink that one, and make a bigger G&T.
Repeat till it works, or you forget what you were trying to prove!
Cheers,
Tom

Whether you are wrong or right, I love the thinking! 😄

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Well, as they say, big theories require bigger proofs!

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My first thoughts were along the lines of flaps like Brian said in post #2. I'm not familiar with heater box design on P38's but if flaps move sideways and have become free to swing (actuator broke or something) it would be easy to imagine turning causing them to swing sideways.

I have known heaters get hotter/colder when turning, going uphill/downhill or with changing engine rpm due to water flow aspects but usually when there's a problem with water flow or just not enough water in the system.

It runs on LPG so will have an LPG pressure reducer plumbed into the heater system. I've known cases where reducers have been plumbed in parallel and most water has gone through the reducer at the expense of flow through the matrix in some conditions but centrifugal force during turning can change the dynamics and pushed more hot water through the matrix. Or plumbed in series and overall flow has been restricted but centrifugal force has caused more overall water flow perhaps by seeing the reducer (if fitted at a high point) is more fully bled up.

Although the problem is described as occurring when the heater is being used, if AC is on it could be due to something that causes the AC clutch to disengage when turning right.

Cornering might imply body roll and/or a change in engine rpm.

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BrianH wrote:

Well spotted. Well first thing would be to see why thats on with Nano or similar diagnostics then?

Dear Richard, Simon and "I can't tell from the site",
Yes its definitely the temperature of the hot air coming out of the vents. The HEVAC work book relates to other issues. When i think it may have come form when i first installed a non sequential system in 2006. Do you think if i plumbed the vaporiser in series rather than in parallel this might not be an issue? All the instructions for all the systems I have seen have a parallel installation but i can see that might result in differential coolant flows. I installed a flow restriction ball valve in mine to allow for this but perhaps i should have gone for series from the start?
So question that follows:
how do you plumb in your vapouriser for LPG, series or parallel?

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Definitely. They always suggest plumbing in parallel in case the particular vehicle controls the heater temperature by shutting off the flow to the heater matrix. Most modern cars, including the P38, have a full flow system where the heater temperature is controlled by directly the airflow through or around the heater matrix. In parallel the coolant will take the path of least resistance so may flow more through the vaporiser or the heater depending on which has the least resistance. When I bought my Classic it was plumbed in parallel and, as it was a single point system, would run on LPG from stone cold. Only problem was, in the winter after 300-400 yards it would die as the vaporiser turned into a block of ice. Obviously the heater was the path of least resistance, so I re-plumbed it in series and that cured that one. My P38 was also in parallel when I got it and when idling in traffic in winter the heater output would drop to vaguely lukewarm suggesting the vaporiser was the least resistive. Re-plumbed that one too and no problems with the heater or vaporiser.

The pipework on a GEMS is also much neater. My vaporiser is on the LHS next to the EAS box and my pipes are output from the inlet manifold to a 19-16mm reducer then 16mm pipe run under the ignition coils to the vaporiser. Output of the vaporiser is 16mm pipe run between the back of the inlet manifold and ignition coils to a 16-19mm adapter and a 90 degree bent hose to the inlet of the heater matrix. Outlet of the heater matrix then runs to the header tank as it should. Some have questioned whether this will reduce the heater output as the vaporiser will cool down the flow before it gets to it. It does but only by a few degrees so when the coolant temperature is at normal running (93 degrees in my case) the heater core temperature sensor reports around 80-85, so still plenty hot enough to heat the car on a frosty morning. On every car I've owned (or worked on) I've re-plumbed like this and never had any problems. There's also a lot less joints to leak.