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2000 4.6 Consuming Too Much Oil (no leakage & No burn & no overheating)

I have a 2000 P38 4.6 with 150k miles on it, and it consumes 1lt of engine oil per 1250 miles. I know this machine can consume oil but this is more than I expected. I left the car on a flat surface and checked under it but there was no sign of leakage. I use it daily in city traffic but it is not overheating, the temp gaug. is always on the middle. I also checked the exhaust and there is no blue or black smoke coming out. My car is in the shop now and they are suspecting the piston ring is gone and I may need an engine rebuild costing a fortune.. My idle rev was low (around 500-600rpms), and car was shaking on N or P idling. I do not what to do and do not have enough resources to rebuild the engine, does anyone here had an experience like this?
 

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Re: 2000 4.6 Consuming Too Much Oil (no leakage & No burn & no overheating)

Oil can only go two places. It can leak out or can be burned out. I really can not think of any options. At 160K miles my rig never lost any measureable amount of oil between 3K mile oil changes. I have a buddy with over 200K on his P38 with no oil loss.

Depending on how it's been maintained it could be oil seals, rings.... Rings can be narrowed down with a compression test.
 

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Re: 2000 4.6 Consuming Too Much Oil (no leakage & No burn & no overheating)

I will learn what they found on monday, but want to be prepared for a negotiation. Hope they find a leakage, rebuild is impossible for now. I will also ask for a compression test, thanks for reminding.
 
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Re: 2000 4.6 Consuming Too Much Oil (no leakage & No burn & no overheating)

Also consider a stuck PCV valve.
 

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Re: 2000 4.6 Consuming Too Much Oil (no leakage & No burn & no overheating)

Do you know more symptoms of a stuck pcv valve?
 

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Re: 2000 4.6 Consuming Too Much Oil (no leakage & No burn & no overheating)

i don't know of a PCV valve as such, there is a oil separator that should be nice and clear (as the pipes too) if these are crud-ed up the pressure will find the next easiest path of escape and that usually is out the rubber rocker gaskets also pushing oil out to lesser or greater extent depending on its location.
 
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Re: 2000 4.6 Consuming Too Much Oil (no leakage & No burn & no overheating)

Larry S: Yes, I am just using the 'generic' terminology 'PCV valve' which manifests itself as the oil separator on a P38, which essentially serves the same purpose of course (and can stick shut, too) and is there to relieve 'excess' pan pressure [as you implied.]

eek55: One of the symptoms of a stuck (open) PCV valve is that there are no obvious leaks etc (and no compression problem either) but you loose ~ ml/mile with a hot engine..... since the oil [vapours] are thus sucked continously 'up and out' !
 

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Re: 2000 4.6 Consuming Too Much Oil (no leakage & No burn & no overheating)

it can crud up, but it doesn't move does it?
 

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Re: 2000 4.6 Consuming Too Much Oil (no leakage & No burn & no overheating)

The shop is a one I trust, but I unfortunately believe they will skip controlling the oil seperator and blame inside, offering a rebuild. I believe it is too early for this engine to rebuild in addittion (assuming proper maintenance).

I will tell them to check oil seperator, maybe they think I am an expert and put me in the "not robbable" category. The only thing now is to find its name in Turkish :)
 
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Re: 2000 4.6 Consuming Too Much Oil (no leakage & No burn & no overheating)

Larry S: I must say I have always assumed it must move or else it is just a flimsy piece of plastic with a zig-zag path through it in a steel tube (?!)... and how would that work (!?) but it is more likely to get full of crud than anything else, that's a fact !

eek55: Just find the Turkish phrase for 'Valve cover Spiral Oil Separator' first !! (and then maybe they will charge you less..?)
 

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Re: 2000 4.6 Consuming Too Much Oil (no leakage & No burn & no overheating)

Thanks for that, I am also looking for it in Rave, in case they do not get the name I can show the part :) I feel better now, looking forward to hear the news tomorrow and missed it..
 

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Re: 2000 4.6 Consuming Too Much Oil (no leakage & No burn & no overheating)

fair enough, but where's it going to move to and what difference would it make anyway, its in an enclosed tube.

It's an oil separator and is indeed just a bit of plastic that i guess as the oil mist makes its way through the zig zag path it gets taken out of suspension and dribbles back into the RHD rocker leaving largely clean air for combustion.
 
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Re: 2000 4.6 Consuming Too Much Oil (no leakage & No burn & no overheating)

You may be right (that it does not close) but then there does not appear to be enough of a path for the hot oil vapour to condense.... ?

What I do know though is that if it is removed the oil consumption increases.

[As I am sure you are aware a 'conventional' PCV valve is usually a spring-loaded device...]

What I also know is it is a 50c piece of plastic for $5 !!
 

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Re: 2000 4.6 Consuming Too Much Oil (no leakage & No burn & no overheating)

Just wondering, when you know that you need a rebuild? Noise, performance, faults?

Btw, I searched the part on some online stores and could not find it, is it something you replace or just clean?
 

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Re: 2000 4.6 Consuming Too Much Oil (no leakage & No burn & no overheating)

If necessary [its broken, missing, brittle] google search part No.
LLJ000010


but you can just clean it and the rocker tube (to manifold) and the other side (to throttle body) but this side doesn't have an oil separator, if its been well maintained these will not be crud-ed up.

It may just be a piece of £3.20ish plastic but it's a designed bit of plastic and its for that your paying.

You said it Davewp38, you know oil consumption goes up with it removed in which case the oil separator does its job (funnily enough) and the LR engineers (funnily enough) more or less know what their doing and your assumption the vapour path is not long enough is wrong, not to mention a contradiction.
 
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Re: 2000 4.6 Consuming Too Much Oil (no leakage & No burn & no overheating)

'Funnily enough' you maybe missed the point Larry S. ! - If you take out this (cheap/nasty) ‘plastic baffles’ oil separator entirely it just makes a bigger hole, ~ 10 times the diameter of the (usual) zig-zag path…. And that causes the (extra) oil to be lost, not the length of the path - as the oil ‘collected’ by this device (mainly by being slowed down and hitting the baffles) is actually in the form of small droplets suspended in ‘air’ rather than actual oil vapour of course. To that end it 'does its job' - but 'less rather than more' as there are much better ways !.

I am exactly not sure how a lengthy diatribe on 'fluid dynamics' and/or 'the relative effectiveness of different designs of oil separators' will help eek55, in fact it basically won't, but based on your comments and also for the sake/hell of it:-

- If LR really knew what they were doing they would not have used such a cheap piece of plastic which blocks, gets stuck in situ and often breaks on removal…. And does not even get replaced during servicing ?

- If LR really knew what they were doing then a different device would have been used: For example the 'cyclone' type of separator and/or a proper larger-bore (and metal) PCV valve (and preferably on both banks) represent ‘real engineering’ techniques ?


Anyway, if anyone was actually ‘wrong’ here it was those famous LR 'engineering practices' – again !

LR please note... a 'proper', unblockable, long-life 'cyclone oil separator' design ! (and yes - its a cross-section !)
 

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Re: 2000 4.6 Consuming Too Much Oil (no leakage & No burn & no overheating)

Wait a minute - it seems that LR must already have known about these cyclone types.... but obviously 'proper' ones cost more than the £3.20 P38 variants !?!
 

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Discussion Starter #18
Re: 2000 4.6 Consuming Too Much Oil (no leakage & No burn & no overheating)

So I will take the day off from work and go to the shop and check the oil pipes and the inside to see the seperator, and let you know what they tell. Maybe they find a sign of leakage or that common coolant fluid mix issue. If it needs a rebuild, I will have to do it sooner or later because I love this car and a brand new one costs nearly 10 times I paid.
 
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Re: 2000 4.6 Consuming Too Much Oil (no leakage & No burn & no overheating)

(Ah, good, we're back on topic !); That's a good plan, eek55, but note that these plastic items are very brittle. If it is within your capabilities consider a compression tester also (which is basically a pressure gauge you fit in place of the spark plugs in turn) - although your oil loss is still quite slight and so you may not actually see any 'big' problems with (or differences between) pistons/rings... ? If you do this yourself and you tell your garage about it you are even less likely to be overcharged by them !!
 

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Re: 2000 4.6 Consuming Too Much Oil (no leakage & No burn & no overheating)

well it's not going to help anything but the burden of proof is with you (or me) not LR engineers, you only just found out the PCV system isn't based on a spring valve, everything else is assumption including my theory on how the oil separator actually works.
 
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