Changing the engine oil and filter.

[GBMUD]

On the subject of hot or cold oil, I have understood the following. If the oil is hot and the car recently run then all the sludge and nasties are suspended in the oil and therefor come out with the oil rather than remaining in the engine to contaminate the new oil. Any oil around the top end of the engine will be nice and thin and will soon run down into the sump. The alternative being that all the sludge will have all settled out in the sump. It does not take long for oil, even cold, to do this as otherwise all the oil would be at the top end after a few minutes of driving...

I guess that there may be a case for keeping the oil cold and thick in the hope that it will pick up the sludge on the way out. I am no expert in fluid dynamics but changing it hot seems to make sense to me.

Chris

[muddyplugger]

Good simple basic information is all some readers are looking to find, others are into technical threads, personally I believe informative threads like this oil change & the fuel filter change are what the tech archive needs to encourage those completely new to the LR scene.

so come on guys, please don't slap each other down, we're all here to learn & help -- at least I am

Hear hear, in fact I wish some one had done a similar thread on replacing the Front Output Shaft on the transfer box before I did mine. The nice Mr White90 described to me how to do it!

Can someone do a 'How to Replace a UJ' for simpletons like me?

[Les Henson]

Can someone do a 'How to Replace a UJ' for simpletons like me?

Now there's one hell of a coincidence! I just happen to have a certain Dr Goons 'red shed' (300TDi CSW),

outside my house at this minute - failed the MOT as well!! A few more techy threads will be forthcoming.

The front propshaft UJ's have gone to the cleaners, so how to bod -erm professionally replace one will be forthcoming

Les.

[unclebill]

here, here. I'd like to see more posts like these, starting at the basics and building up to the more technical stuff. I know there are plenty of young 'uns who frequent this site who would benefit from such basic info. I'll be emailing them to my 17 year old and hopefully he'll have a bash at it himself instead of running to me every time his poxy Corsa misses a beat. I for one am looking forward to the next instalment of Les' "mini series" and c'mon guys, lets have a little more input with tricks of the trade etc. etc.

Keep up the good work Les.

Ade

Good simple basic information is all some readers are looking to find, others are into technical threads, personally I believe informative threads like this oil change & the fuel filter change are what the tech archive needs to encourage those completely new to the LR scene.

so come on guys, please don't slap each other down, we're all here to learn & help --

Six pennies worth, totally agree, thanks Les, personally and i'm into engineering for a living, when i got my rangy found this forum very helpful, especially with the air suspension, that modern eletrickery is damned baffling stuff.

[Dr Goon]

What did it fail on Les - anything unexpected?

Now there's one hell of a coincidence! I just happen to have a certain Dr Goons 'red shed' (300TDi CSW),

outside my house at this minute - failed the MOT as well!! A few more techy threads will be forthcoming.

The front propshaft UJ's have gone to the cleaners, so how to bod -erm professionally replace one will be forthcoming

Les.

[Gromit]

If you take a look at the topics on this forum, they are about radical and non standard modifiction to trucks, namely suspension, winches, roll cage etc: stuff that is well beyond the Haynes manual one spanneer level and that is what make the forum worthwhile. So a post about something basic like this is almost taking the mick.

It was the fact that this forum (and its previous incarnation) wasn't soley radical stuff that allowed me to get started maintaining my own truck.

I can now do all the basic stuff which gives me the confidence to launch my self into the most daunting tasks and I try to enrourage and help anyone else starting off to do the same. I feel it is part and parcel of land rover ownership. It's not a mode of transport, it's an education.

Looking at Les' simpler posts, while I know how to do the jobs, I'll still read them. It's always interresting to see how other people do things and you might even learn something new.

Look at the replies. Not everyone on here is running a truck they scratch built with 2 LR axles and a welder.

[isuzurover]

I always change my engine oil when hot. As mentioned above there is no guarantee you will get everything (sludge, etc) out when the engine is cold. If you use good oil and change the oil regularly, it shouldn't matter, but to be on the safe side, why not, it only takes a few minutes extra.

I have pulled down a couple of engines (not previously serviced by me) for rebuilds or parts, which have had deposity of semi-solid sludge in parts of the engine. I don't know if this was oil sludge or if the owners had put engine stop leak in, but either way, why take the chance.

Incidentally, filters (oil and air) become more efficient the more dust they collect (at the expense of increasing pressure drop). So leaving an oil filter on a bit longer will not do any extra harm, as long as it doesn't collect too many particles and the pressure drop across it becomes too high.

[MarkieB]

I'll just say that although I knew V8s' oil pumps needed special care, it's news to me that you shouldn't change oil+filter at one time, so there's Mileage in even the most basic posts, cheers Les

what happened to Hillbilly + Minivin then?

[BogMonster]

The V8 rule only goes up to a certain age of engine, newer ones like wot is nestling gently in the engine bay of my DiscofairyTwo have no problems as the oil pump is a different type, one is gears and the other is rotors but I can't remember which is which I'm pretty sure that my last (1996 model) V8 had the later type of pump though, so it may be all the engines with a serpentine belt arrangement or perhaps even all 3.9s onwards.

I think the way to tell is the suffix letter on the engine number, up to so-and-so suffix has one sort of oil pump and you need to be careful about it not draining out, so-and-so suffix onwards has the later pump so no problems. But as I don't have the so-and-so bit of information this post is only faintly useful really isn't it

Edited to say that RAVE says the 94-98 age Discoverys have a gear oil pump so the old one that you need to be careful with must be the rotor type pump, but I can't find any info on the changeover point at the moment

[Cal]

I for one am well chuffed that Les has taken the time to make this post - I'm absolutely rubbish at most things mechanical but am well keen to do more bits and bobs around the Disco myself - did my first fuel filter the other day and am gonna to do the next oil change myself as well - so thanks Les.

Not wishing to add fuel to any potential arguments, but I find it really helpful to have posts like this, as well as all the really techy stuff - mainly cos I can actually understand this post! ;-)

[Les Henson]

What did it fail on Les - anything unexpected?

O/S/F wheel bearing feels rough. No play, so new bearing (and another tech post)(I should be paying you! ) Steering linkage (uj) are fine. Wobble might be a wobble monster!

Les.

[geoffbeaumont]

The V8 rule only goes up to a certain age of engine, newer ones like wot is nestling gently in the engine bay of my DiscofairyTwo have no problems as the oil pump is a different type, one is gears and the other is rotors but I can't remember which is which I'm pretty sure that my last (1996 model) V8 had the later type of pump though, so it may be all the engines with a serpentine belt arrangement or perhaps even all 3.9s onwards.

I think the way to tell is the suffix letter on the engine number, up to so-and-so suffix has one sort of oil pump and you need to be careful about it not draining out, so-and-so suffix onwards has the later pump so no problems. But as I don't have the so-and-so bit of information this post is only faintly useful really isn't it

Edited to say that RAVE says the 94-98 age Discoverys have a gear oil pump so the old one that you need to be careful with must be the rotor type pump, but I can't find any info on the changeover point at the moment

Serpentine/distributorless engines have an oil pump driven off the crankshaft, which is supposed to be a vast improvement on the older gear ones driven off the distributor. I'm not sure how the newer one's constructed.

I didn't know you weren't supposed to drain the sump and remove the oil filter at the same time on the old V8s - I always have and never had a problem (I do prefill the oil filter). I can't actually figure out why the sump being empty would make any difference?

[Diff]

I didn't know you weren't supposed to drain the sump and remove the oil filter at the same time on the old V8s - I always have and never had a problem (I do prefill the oil filter). I can't actually figure out why the sump being empty would make any difference?

I believe the theory is that you should drain the engine oil first, so that the filter, pump and associated galleries is/are still full of oil, this will prevent/restrict oil from draining out of the oil pump and pick up pipe when the sump oil is drained(rather like turning a container full of oil with a very small hole in the top, upside down).

You then refill the sump with new oil before removing the filter. This will raise the oil level within the oil pump pick up pipe and slow/prevent any more oil from draining out of the pump when the filter is removed(which will allow air into the system which if the sump was empty would cause faster/more complete draining

of the pump and pick up pipe).

Regards,

Diff

[Bull Bar Cowboy]

Diff has the answer ( well, that’s the way I have always understood it)……………. this was the theory and I believe has happened to some unfortunate souls ……………. the pump is OK when its full of oil, but does not suck air very well at all

Geoff is also correct that the later crank driven pumps on the dizzyless engines do not suffer from this problem. This is a much better pump and these engine are built a little better to take advantage of modern oils

These pictures may help to show the situation a little clearer……………

Here is a pic of the oil flow on the older engine....... pump on the side of the front cover

And here is the newer engine........................ crank driven pump in the front cover

Sorry for the thread Hi-Jack Les

HTH

Ian

[Dr Goon]

(and another tech post)(I should be paying you! ) Les.

Sounds good to me - I am sure we can agree a price

[02GF74]

early v8 with cam driven oil pumps had rotor type gears, two flavours as shown here

the later ones have like a toothed cog running inside another cog of larger diameter but fewer teeth, not sure what that arrangement is called.