3.8 NP Using oil

[Goody]

Hi all, Ive just upgraded from my trusty old NL to an NP with a 3.8 petrol donk. Prior to picking her up she had both rocker cover gaskets replaced, new cam seals and spark plug tubes. It also had a service as part of the deal.
I just drove down to Melbourne and back to Brisbane over a week and about 3/4 of the way I checked the oil and she was down to the low level mark on the dip stick. I added about 500mls and that brought it up to full. I have found no signs of oil leaks so therefore she must be burning it. She runs real well and has plenty of power. There is no smoke on startup and none can be seen in the rear vision mirror. When I inspected her, I ran her at idle for a long time to see if there was any smoke from valve stem seal and she was clear of that.
She has 284 ks on the clock, would this sort of oil consumption be considered as OK for an older girl or do you think she has more underlying problems.
Cheers
Goody

[disco stu]

When did you check the oil prior to finding it down to low on the trip?

[psproule]

If all it has done is a bunch of short trips before the long trip you have just taken it on it may well be normal. Often a good hard run will burn off pollutants and dilution of oil and drop the level. I wouldn't stress unless the consumption pattern continues. If you want to be cautious you could also do an oil change to ensure it has a quality oil / correct grade in it.

Pat

[BruceandBobbi]

Did you check the oil level when you picked the vehicle up?

[nj swb]

This is a common experience, as indicated by psproule. I'm bored, and I've been drinking, so feel free to move on.

All Otto cycle reciprocating piston internal combustion engines burn engine oil. In good condition, they may not burn much, but they're burning it. This is a simple, unavoidable consequence of how they work. It's happening, it just may not be visible.

How can it not be visible?

The fuel (and, to a much lesser extent, the oil) we burn is a hydrocarbon - consisting largely of carbon and hydrogen. When it burns, the most significant byproducts are carbon (soot), oxides of carbon (CO2) and oxides of hydrogen (H2O).

We all know all about the CO2 entering the atmosphere and changing the world as we know it (regardless of your views on climate change, whether you believe it or not, emission of CO2 from our tailpipes is causing our world, as we know it, to change).

The carbon, caused by incomplete combustion of the hydrocarbon, builds up over time in our engine oil, causing it to turn black.

Most of the H2O gets sent out our exhaust pipe, along with the CO2, CO, NOx and who knows what other nasties that have yet to make it through to our collective conscience.

Some H2O doesn't make it out our exhaust pipes, but condenses (who knows where ) and makes it into the sump. I'm not sure whether it sinks to the bottom of the sump, under the oil, or becomes suspended in the oil (thanks to all the detergents and other additives that are added to our oil to help them to look after our engines) but either way, the H2O that condenses in our engines and collects in our sumps helps to maintain the appearance of our oil level on our dipsticks.

When we then go for a long drive, many hours of running, our engine and everything in it heats to the point that the H2O that had collected in the sump / was suspended in our engine oil is driven off through the crankcase ventilation system, sucked into the intake and sent out the exhaust. So, at the end of the drive we notice a sudden drop in oil level in the sump - which is not because we've suddenly burned oil, but because we've suddenly driven off the moisture that was masking that we've always been burning oil.

If the sudden drop comes suddenly, not long after a service and oil change, that's a problem to worry about.

If it comes after 12 months of "soccer mum" duties before an impromptu big trip, not so much to worry about.

If you're really worried, always do an oil change before a big trip, whether it's due or not. Waiting until you return is not a particularly good idea.

[Goody]

Yeah I did check the oil before I left and it was a little down on what Id expect from a service. In saying that there was a gap of 800 kms from when the service was done and when I picked it up, that was in 7 days. In that time the gaskets were replaced and work was done.
I dont know what sort of running around was done prior to my time, but the service records show it was serviced every 10k from the time it was bought, with in reason. Timing belt was done for the first time at 238ks so someone was rolling the dice, haha.
No biggy really, I will keep an eye on it from now, its had most things done in its time and I enjoy driving her. The 3.8 compared to the 3.5 has more power and is more ready to take off, Im not sure if that the fly by wire compared to a cable but she sure has more balls.
Cheers all
Goody

[erad]

You can have a leak from the rear of the rocker covers. One side has a plug, the other a cam angle sensor. Oil can slowly leak from the seals here (not the rocker cover gasket) and drip onto the exhaust pipe and burn away without you knowing it. Run your hand across the rear of the rocker covers and see if there is any oil there.

[4ePikanini]

Check the oil first thing in the morning.

Checking the oil after you have been on a drive and then coming to rest will give a different reading.

I like to see the car 5mm overfilled when I check it first thing in the morning when the car has been standing overnight.

[Having Fun]

Ours (3.8 NP) uses very little oil around the suburbs during stop/start slow city traffic.


On the highway it uses oil a bit more cruising at the speed limit, but not a huge amount. Adelaide to Mt. Gambier & back (about 900km including side trips), probably around 500ml.


Towing is a completely different story! Adelaide to Alice towing a small caravan, it left home with the oil on the full mark & arrived in Alice on the very bottom of the dip stick. Same for the rest of that trip.


Back in suburbia, back to not using much oil at all.



The oil gets changed in it at around the 5K mark & is never black.

[dmenheere]

you might laugh but it can't hurt to try this

https://seafoamsales.com/product/sea-foam-motor-treatment-oil-fuel-additive/

I bought mine with 250K on it and it burned a lot of oil but I tried this stuff and much better now. It now has over 435K so doesn't seem to have hurt the engine at all. I also use Rotella diesel oil now with the cleaners in it. My guess is the oil rings on the pistons get gummed up over time and don't seal.

Can also check the ultimate source of knowledge ... Youtube :-) and watch it in action.

YMMV,

Dave

[Yacatac]

Our has used oil ever since we bought it, around 7 years go. We only do highway driving and I normally need to top it up evey fortnight or so - we’d do approx 750kms per week per week. It now has 350k kms on it. We bought it with 40k. Our mechanic says the stem seals need sorting. 3.8’s they just seem to need a top up as a matter of course.

[erad]

I had a 3.5 L NL Pajero, and it used oil from new. I attribute this because of the running in period. When it was delivered, I was in hospital and my wife took delivery. It was about 2 months before I could drive it. Nothing over 80 km/h. It used no oil for the first 2000 km after an oil change, then about 0.5 L up to 5000 km. I changed the oil every 7500 km and it was down to the low mark. At the same time as buying the Pajero, we bought TF Magna 3.0 L manual transmission which was about 2 years old, an ex Dept of Environment car. It used zero oil - the oil was still on the full mark when it was changed at 7500 km. The contrast was quite marked.

Running conditions for both cars wee much the same - mainly long distance (100+ km) at 100 km/h. The oil consumption of the Pajero seemed to increase after 2000 km, and I blamed the breakdown of the additives in the oil for that. I don't think there was dilution because in particular the Pajero rarely had short trips whereas the Magna was the shopping trolley for us. Both cars ran on LPG, and the oil barely changed colour between changes.

Years later, I managed to drop a washer into the intake (sad story) and the engine ad to be stripped down (twice - even sadder story). When it was down, I looked at the bores and I could clearly see the original honing marks on the cylinder walls. I put new pistons and rings in 2 cylinders because the pistons were damaged. I checked the end gap in the compression rigs and they were still within original tolerance, so I didn't touch the other pistons. Oil consumption didn't change when the engine went back together.

[Blu Coastie Pajero]

Hi dmenheere

How much to you put in the oil ? Any when ?
I have just come back from a 600km regional trip and the pajero nm used a fair bit of oil
The mechanic said he thinks its vale stem seals and at 200000km wanted to do
Head reconditioning/service $1243
Gaskets $655
Timing Belt/water pump $635
Spark Plugs $173
Leads $352
Labour $2200
Total $5297 AUD

I have shopped around for parts and the mechanic seems happy if i supply my own and source a head reconditioner myself and got it down to $3628. Still alot money to spend coming out of COVID.

My landrover mate said oil is cheap just keep it topped up, his land rover drinks it

[disco stu]

$3600 is a lot of oil! Is all that other stuff due anyway, or just going to do it at the same time?

Try rockauto for parts. Absolute bargain prices compared to buying here, even with the crap exchange rate

[Lance]

I often wonder what oil the smaller workshops use when doing a service.
Do they buy in the specified oil for a particular vehicle or just use whatever is in the 44gal out the back.

Dare I say it, I imagine some would use the same oil for every vehicle that comes in the door.
I do hope I'm wrong.

The ppl at my service place buy the correct oil in packages and leave excess in the vehicle for me.