To oil change or not to oil change

Submitted: Wednesday, Jul 06, 2005 at 18:21
ThreadID: 24499 Views:2820 Replies:17 FollowUps:6
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Interested to know of the benefits of changing the oil every 5000k's when the logbook reccomends 10,000k's. It says 5000 if in trying conditions, but around town driving in Adelaide isn't really that.

I have been doing changes every 5000, but am starting to wonder their worth.

At $60/11litres of Penrite, and $30/oilfilter, the cost/100,000ks is $900 more! Is it really worth it?

Fanks Everyone
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Reply By: Exploder - Wednesday, Jul 06, 2005 at 18:33

Wednesday, Jul 06, 2005 at 18:33
In the long term I would say yes otherwise not really.
With today’s modern oil’s 10,000k’s in adequate most car company’s now recommend 15,000 and up to 20,000k’s I personally think that is too long for the same oil to be in an engine.

On mine I started doing 5000k’s changers at 100,000k’s just for some added protection but less than 100,000 I wouldn’t worry about it.

10,000k changers are adequate for most except on Japanese Diesels
AnswerID: 119148

Follow Up By: WheelTravel - Wednesday, Jul 06, 2005 at 18:36

Wednesday, Jul 06, 2005 at 18:36
Japanese Deisels huh? Like maybe a 1HZ in my cruiser. Why, they are one of the best engines around.
FollowupID: 374308

Follow Up By: Exploder - Wednesday, Jul 06, 2005 at 19:01

Wednesday, Jul 06, 2005 at 19:01
The oil turn’s black and sooty real fast as they get some k’s on them. They are also known for sludgging up internally are they not? Just about all the posts I have read on hear and the people I know with Toyota/ Nissan diesels change their oil every 5000k’s and this is one of their reasons.

I am not nocking the engines they are solid.
I remember striping a 1HZ diesel once and my hands were stained black nothing like from a petrol engine.

Doesn’t Toyota recommend 5000k changers on the Hilux?

If you do it every 10,000k’s it won’t be a problem I am sure, the oil will just be a little more dirty, If I had one and it was getting up over 100,000k’s I would be doing it every 5000 just to keep it that little bit cleaner and the oil fresher. If it gets done at 10,000k’s it is not going to suffer a major mechanical meltdown anytime soon.
FollowupID: 374312

Follow Up By: Member - Davoe (Widgiemooltha) - Wednesday, Jul 06, 2005 at 20:49

Wednesday, Jul 06, 2005 at 20:49
Wheel travel perhaps try different oil. with 5k changes the most expensive oil doesnt get you much benifit. I have been using shell Helix for about 20 bucks less than you say also try 10l of oil in your 1hz. That has done me fine in my 2h and 1hz filling to the f mark and about 3mm over.
FollowupID: 374322

Reply By: cokeaddict - Wednesday, Jul 06, 2005 at 18:50

Wednesday, Jul 06, 2005 at 18:50
I look at it this way,
Cars are an investment, if you plan on keeping it for a very long time (as i do) then 900.00 dollars is cheap insurance for a Diesel compared to a rebuild at anything up to and over $8,000.00. Besides, imagine breaking down out the middle of nowhere, all because you wanted to save a few hundred bucks. Sit down and work out whats involved in organising getting your 4b home, I can assure you its not going to be cheap, not to mention the time involved.

Sometimes i wonder why go diesel over petrol, but although mine is down on performance over a petrol version of the same, it has many more advantages offroad to me than a petrol one would. Then again, being able to put your foot down just to show others how good it looks heading up hills isnt something that interests me personally. I am in no hurry heading to the camp site or heading back home, as long as i enjoyed what i did is all that matters to me.

No offence to petrol owners here , its just how i see things (personal)
AnswerID: 119149

Follow Up By: Member - RockyOne - Thursday, Jul 07, 2005 at 08:00

Thursday, Jul 07, 2005 at 08:00
The way I see it,the oil does'nt "wear out",only the motor does..What should decide the issue is the degree of contamination which has been introduced into the oil by the motor and outside influences such as dust etc..After all,it is possible to buy oil which has been re-cycled (de-contaminated)..Don't skimp on three important products for the engine (1) Oil (2) Oil filters.Valvoline & other quality brands (3) Air filters..I would'nt trust a paper one unless I was driving on wet roads all the time. (Do your motor/air filter a favour and stay well clear of any vehicle that has a flat,vertical rear on the highway..Your intake sucks in dust you can't see (the worst type..abrasive) and just watch the dust swirls off to the left of the truck etc you are following..Guess where a lot of that is going..Back off 'till you are ready to pass..Helps? Rgs RockyOne..(I drive dsls/ 'em all)!MPG:6!
FollowupID: 374353

Reply By: bushy04 - Wednesday, Jul 06, 2005 at 19:32

Wednesday, Jul 06, 2005 at 19:32
Hi my Triton recomends a change at 15000k however in the box from the oil filter is a notice saying that the oil must be changed at 10000k????
I like to keep my veshiles for the long haul so I change oil and filter at 7500k.
This is after working in an engine reco shop.
You could always tell those motors that were not properly maintained so the choice is up to you, if you intend to keep it long term then consider the extra cost as an investment. cheers.
AnswerID: 119154

Reply By: Rosco - Bris. - Wednesday, Jul 06, 2005 at 19:45

Wednesday, Jul 06, 2005 at 19:45
G'day cobber

With the Fender, oil changes are recommended at 20k intervals, mostly due to the fact they have included an additional centfifugal filter, much the same as on heavy equipment and trucks. This apparently removes the heavy particulate matter which is the primary cause of sludge etc.

However, having said that, I feel more comfortable with 10k intervals, so I'm going down that line.

But I take your point and tend to agree .. sometimes we tend to be a tad overly conservative and in effect throw dollars away by changing oils unnecessarily.

I suppose at the end of the line it all depends on vehicle usage and what you feel comfortable with .. bearing in mind short stop start city driving can be as hard as heavy offroad conditions on your donk.

Personally I reckon 5k intervals is possibly a tad too cautious .. but it's really your call.

AnswerID: 119157

Reply By: Muddy 'doe (SA) - Wednesday, Jul 06, 2005 at 19:51

Wednesday, Jul 06, 2005 at 19:51
Hi Wheely,

The reason behind my Prado TD having 5,000km oil changes is to do with trapping soots in suspension in the oil. This is an anti-pollution measure and is designed to stop the reduce stuff going out the tail pipe.

This means that the oil loses lubricity after lower kms and needs to be changed. Toyota recommends changing the filter at 10,000km intervals but many people change these at 5,000km with the oil. Can't see the point of putting clean oil in with a dirty filter. My own thought is that the soot being trapped is so small that it does not get caught by the filter anyway, but I could be completely wrong on this!

Anyway - The point is that the oil would probably be fine for 10,000km or even more if the engine manufacturers were not intentionally trapping particulates in it as the anti pollution measure. This of course means that it becomes even more important that the used oil is disposed of properly! But I suppose it is better than having the stuff in our lungs after going out the exhaust.

Another issue you touched on was extreme driving conditions. Toyota actually recommends reducing the oil change interval to 2,500km in extreme conditions. One of the listed extreme conditions is "regular trips under 8km in length". This means all those short trips around town without taking it for a decent drive and letting it get properly warmed up. Sounds like short city trips to me! During the week I get in the car and drive 4km to work and then 4km home every day. I try to make sure I get some longer trips in on weekends but I am concious of this qualifiying as "Extreme Driving Conditions" as the motor does not get the chance to optimum working temperature.

AnswerID: 119158

Reply By: Crackles - Wednesday, Jul 06, 2005 at 19:57

Wednesday, Jul 06, 2005 at 19:57
Gaday WT.
I've had 4 diesel Toyota's all of which I drove hard & only ever changed the oil at 10K with no noticable effect in performance & no premature failure. The longest I keep my cars is around 180K. By using a recomended good quality oil & changing the filters at every 10K, you wouldn't see much advantage unless you intend keeping your bus over 300,000+KM when the additional wear would become noticeable. There are some exceptions like the Hilux which in some models has less than 5 litres in the sump & turns to a black tar by 12K. Turbo models too can benifit from more regular oil changes. I've had 2 1HZ motors & with nearly 10 litres circulating, the oil IMHO neither gets too thick or runny & has no trouble building preasure when starting. Experts have told me that over 10K, alot of the additives in the oil are burnt off or worn out so shouldn't push changes any further.
I think many who change oil at 5K do so out of fear of what may happen if they don't & will probably find they also use synthetic oils, have twin fuel filters, Sat phones & EPIRBS. I think they call it paranoia ;-)
If you reckon $900 can be saved every 100K by pushing the services out, I've already saved $5000.
Cheers Craig..........
AnswerID: 119160

Reply By: Peter 2 - Wednesday, Jul 06, 2005 at 20:16

Wednesday, Jul 06, 2005 at 20:16
Back in the 80's when cruisers had the 2H I know of few people that tried to extend oil changes out to 10k to save money. A couple of them also trashed motors doing it.
My 1hz powered troopy (1990 model) had a recommended change interval of 5k, the later ones have gone to a 10k. As has been said the jap motors are notorious for being 'dirty'.
Because they are 'dirty' you can't buy a diesel cruiser in europe ot the US as they can't meet the emissions regs.
To my way of thinking oil is relatively cheap compared to the cost of an engine rebuild. It also depends on how long you intend to keep the vehicle, we all know the bods that get a new one every two years and don't bother to service it all!
I also suspect that some manufacturers say that the oil can last 20k because they don't intend for the vehicle to last past 5 years anyway!
AnswerID: 119164

Reply By: TerraFirma - Wednesday, Jul 06, 2005 at 20:34

Wednesday, Jul 06, 2005 at 20:34
Yes agree with all the comments, it always gets down to if you are going to keep the car for years and would like to enjoy the reliability and satisfaction of keeping your baby going day in day out, then it's worth it. If you have no intention of keeping the car and plan to sell it soon, then stick with the recommended intervals. Trying conditions would mean running the vehicle in extremely hot and dusty conditions. Heat kills oil, it loses it's viscosity. Dirty air filters, and burnt oil are no good to your engine.
AnswerID: 119169

Reply By: Member - Roachie (SA) - Wednesday, Jul 06, 2005 at 21:43

Wednesday, Jul 06, 2005 at 21:43
I've just read all of the responses above and now I add my 2 cents worth.
My Patrol has done 160,000klm and is almost 5 years old. Until about 1 month ago I used to change the oil and both filters every 5000klm.
I did a lot of question-asking on here over a several month period, about by-pass filtration systems.
This has now led to me fitting a system from AMSOIL (see: This involved removing the rear filter on the block and replacing it with a fitting that had provision for 2 hoses. These 2 hoses (1/2" 400psi hydraulic hose) lead to a dual-head unit which I mounted in behind the bullbar. It has 2 filters mounted on is effectively the same as the OE filter, the other is about twice the size and filters about 10% of the oil at any given time, down to approx 1 micron. By the way, I have noticed that after a relatively short trip, only the big by-pass filter gets warm, the smaller one stays dead cold, indicating that ALL the oil is being processed by the big filter.
The bloke who sold me this set-up has an old GQ ute with 177,000 klm on clock. It has had the by-pass system on since new and has only had the oil changed 3 times since he bought it. The last change was over 40,000klm ago and the oil on the dipstick was black, but did not stain the fingers at all, indicating the lack of soot.
I have spent an extra $300- and bought a box from Castrol, containing 10 separate kits of oil check gear. Whenever I want to do so, I simply bleed off a small amount of my oil and send it off to their laboratory for analysis. I will do this when we get back from our upcoming Simpson desert trip, by which time I estimate I will have done about 8,000 or 9,000 klm on the oil I have in at present. I should also add that i have changed over to the recommended 100% synthetic oil, also from Amsoil. I have stuck with 15w40, but the bloke with the ute said he uses 5w40.
I will report on here in due course once I have had the oil analysed, but so far so good. I'm hoping to be able to stretch my oil changers out to say 30,000klm. As you may have gathered from my original statement about changing every 5000klm, I am not easily given to taking risks; hence the lab checks from Castrol.
As I have said on here before in regard to this matter, I have added a buzzer to my low-pressure oil switch, so I'll know immediately if a hose blows off. I have also fitted a oil pressure gauge some time ago and have not noticed any change in the pressures in the oil with this change.
AnswerID: 119181

Follow Up By: GQ_WA - Thursday, Jul 07, 2005 at 01:03

Thursday, Jul 07, 2005 at 01:03

I have a 1999 GU TD42T and am very interested with this product.

How much does the Amosil unit cost? Other than purchasing it online is it available in any Australian stores. Does the oil light on your Patrol go off faster? Can you send a couple of pics of how it is your setup in your GU?

Please drop me a line at as i do have a couple more questions and hope you can assist.

FollowupID: 374350

Follow Up By: Richard Kovac - Sunday, Jul 10, 2005 at 20:52

Sunday, Jul 10, 2005 at 20:52
It's always a good idea to get a oil sample taken and analysed of the new oil you are going to use and monitor, to use as a base line that you can check against.
The main thing to watch is the (TAN) total acid number, this will tell you when the oil needs changing.
Only cleaning the oil is not enough as there are additives put into the oil for cleaning, anti-foaming, anti-wear and corrosion inhibitors etc. and the viscosity of the oil as it will be diluted by fuel over time.
All of these thing will need replacing over time.
The other thing you need to watch is the total Particle count, again you can have super clean oil (I think 1 micron is a bit low) but a high Particle count, meaning a lot of very small Particles which will erode away metal as much as large ones will scratch them

I'm not having a go at you, what you are doing is the right way to go about extending the service intervals, you just need to be checking the right info.

Best of luck


Richard Kovac
FollowupID: 374766

Reply By: vitara - Thursday, Jul 07, 2005 at 09:04

Thursday, Jul 07, 2005 at 09:04
HI All, reading all this about oil changes scares me as I would hate to add up how much I have spent on oil n filters (genuine toyota filters). I change my oil and filter every 2,500klms without fail so did the previous owner who had it since new every receipt in the log books I even take filter and oil with me when were traveling and do if its due prior to our trip finishing. Will have to keep my wife from seeing this question asked by wheeltravel. She reckons where spending to much on oil etc. Am in the process of giving it a trial run up to 5000klm and see how the oil comes out then. I used to work for toyota and see these things come in seized up, rod hanging out the sides due to lack of oil changes so I am very wary, probably to the extreme but as I said to my wife its easier to find 40/50 bucks than 6k for a engine rebuild so thats how I've been getting away with it with her. Vehicle is d/cab lux with 2.8 diesel with 270,000klms still going well. (slug but gets me where I want to go) Take Care Vitara
AnswerID: 119235

Reply By: Member - Tonester (VIC) - Thursday, Jul 07, 2005 at 11:11

Thursday, Jul 07, 2005 at 11:11
I don't know the validity of this, but someone told me once that as long as the oil filter is kept in good nic and/or replaced regularly, the oil can be replaced less frequently. Maybe someone's got comment on this approach?
AnswerID: 119258

Reply By: ev700 - Thursday, Jul 07, 2005 at 11:57

Thursday, Jul 07, 2005 at 11:57
From heaps of research i think a centrifugal filter is the ways to go and it was pleasing that LR took the initiative with factory installation of centrifugal filters in Defenders.

I wish the other manufacturers would be as conscious of the environmental and cost advantages of centrifugal filtration.

I would like to instal a centrifugal filter on a 100 TD Cruiser but to date have not been able to find anyone in SE Qld who has done it. There are units available and apparently it is a question of where to tap into the oil.

Bit of a surprise that it hasn't been done given the number of mechanical engineers and skilled mechanics with expensive fourbies.
AnswerID: 119268

Reply By: Member - Collyn R (WA) - Thursday, Jul 07, 2005 at 14:22

Thursday, Jul 07, 2005 at 14:22
Muddy's advice is about the best.

Oil change interval needs to be inversely related to typical trip distance especially if the typical drive is too short to allow the oil to heat up sufficiently to boil acid deposits caused by condensing semi-burnt fuel dropping into the crank case.
A giveaway here is that oil level tends to stay constant as it is being topped up with dilute acid!

That, and ingested dirt are the real engine killers.

Would suggest 2000 km interval if the vehicle is mostly city bound and used for trips of less than (say) 10-15 km.

On the other hand you could (assuming warranty permits) safely extend this to 10,000 km if travelling long distances on bitumen (ie, dust-free) highways.

I had personal experience re this during my time with GM Research with controlled experiments with two large transport fleets - one doing street coal deliverym, the other long distance transport. With oil changes at normal iontervals the difference in engine life was in a ratio of well over 30:1. Truly!
Collyn Rivers

AnswerID: 119282

Reply By: phil - Thursday, Jul 07, 2005 at 17:52

Thursday, Jul 07, 2005 at 17:52
Lots of interesting comments so far!
However no one has mentioned the need to change oil every 6 months, even if less than 5000k. This is because corrosive products build up with time.

Phil I
AnswerID: 119302

Reply By: *Jared* - Saturday, Jul 09, 2005 at 23:55

Saturday, Jul 09, 2005 at 23:55
Interesting coments above.
I believe the centrifugal system would be benifical if you want to extend change intervals. The soot ( which is partly caused by poor combustion because of the crap diesel sold in Aus. ) is what causes the sludge which does the damage and these spinners remove this. You only have to look at the paper from one of these to see how much they remove.

The quantity of oil in the system is what should determine when to change the oil as it can only hold a set amount of soot in suspension. This soot is fine enough to go through the filters which by the way, if you use a filter which is good for 1 micron you will be straining out the wear package additives that are put in the oil. Your filter will be in bypass and you won't get any filtation. Leave the standard filter system alone.

Adding a cooler which will keep the oil cooler as well as add to the total system volume will also help. Any performance shop should be able to to put you onto different types of pumps which can do this without touching the standard system.

Having run a 4.2 GQ patrol well past 350 000 km with 10 000 km oil changes I
found that it did start to struggle after about 280 000 km and the power loss was very noticeable.
I guess if you want keep the vehicle do the 5 000 km changes.
thats what i think
Bazzad ( father of Jared, its great to have passed on the passion)

AnswerID: 119616

Reply By: Alloy c/t - Sunday, Jul 10, 2005 at 01:20

Sunday, Jul 10, 2005 at 01:20
Simple , A=$ .......scimp on A=$ ,,,, want your pride and joy to die an early death ,,,, DONT BOTHER giving a full service at any time ,,,,,LETS just watch A motor DIE.
AnswerID: 119628

Reply By: sjy120 - Saturday, Jul 16, 2005 at 19:09

Saturday, Jul 16, 2005 at 19:09
Just a tit bit of info regarding oil changes , in some european trucks , they take the oil changes out to 100,000 km's . Yes 100,000 km's .
AnswerID: 120667

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