Oil usage and readings very strange - MY2014 TDV6

[75Vette]

Hi all, first post!

Thanks to the community, I have referenced this forum a lot over the years.

Just did an oil and filter change on my 2014 Disco 4 TDV6 and was left scratching my head. Looking for thoughts on what to do next.

Vehicle history:

• Bought 2016 at ~50k kms, previous owner was Sydney based and vehicle appeared to have had an easy life.
• I sold it in 2021 at ~90k kms to a mate as I was going O/S for three years.
• I re-bought it from the same mate at ~180k kms as I returned home and he was now going O/S for three years! (lol)
• No engine issues recorded the whole time.
• I use a (newly aquired) Foxwell 624 Elite to check my own codes, no powertrain issues or recorded fault codes (of concern) in the past 20k.

Car last serviced with him at 183k. It's now at 1 year on and 203k so I realised it was overdue (20000kms from last service) and decided to start with fluids and filters.

Oil and filter service (today):

• I checked the levels before starting with the Disco completely cold and the digital readout was one notch below the center and said "Add 0.5L".
• I started the engine, let it warm for 10 mins, then let it cool for 30 mins before starting the oil drain.
• I use a 7.5L Boston Mechanics oil extractor (through the breather), which I used on the same vehicle the first time I owned it, so I know it works well.
• Using a digital baggage scale I weighed the oil extractor before use to get a tare weight so I could measure the amount of oil extracted (for interest, it weighed 2.5kg with no hoses attached).

Results:

• Oil cap cracked open to allow the system to drain more freely.
• Pumping the unit started to extract oil with 5-6 pumps, I kept going to 20 pumps to establish a nice flow.
• Oil was extracting quickly and freely.
• Within ~5 minutes (possibly quicker), I could hear the extractor sucking to suck air and the flow slowed to a trickle.
• I repumped to create a new vaccumm but there was little left to extract.
• Total in the first go was 3 (edit) kg or ~3.6 L. This was visible on the extractor, which was less than half full, and confirmed with the baggage scale at 5.5kg (2.5 tare + 3.0 oil).

Fault finding:

• Concerned, I left the vehicle sit for another 30 minutes to allow more oil to drain and tried again.
• Only ~200-300ml more was extracted before I was again sucking air from the sump.
• I cracked the filter housing and unscrewed completely to allow the filter to drain, and left the vehicle for another 30 minutes to allow even more oil to drain to the sump.
• Only ~200ml more was extracted. Total, 3.5 (edit) kg, or ~4.2 L.

****.

• Finally I decided to confirm the sump was indeed empty by adding 200ml of fresh oil and seeing if it would extract.
• Added oil, waited 10 minutes for it to settle at the bottom of the sump and pumped to extract - almost all the 200ml was extracted before I was again sucking air from the sump.
• It definitely appeared to be EMPTY. Again, only 3.5L came out of the engine.

Final steps:

• I checked the old oil filter very carefully (every fold) for any metal or debris, nothing at all found.
• Replaced and refitted the filter, torqued housing to 25nm.
• Confused by why (seemingly) having only (edit) 4.2 L of oil in the system didn't trigger any dash warnings, I checked the digital oil quantity and it was showing as "below minimum", so at least the sensor was doing something.
• I added exactly 4L of fresh oil (5W40 full synth) and checked the digital readout - it was still below minimum.
• I added exactly 1L (5L total) and the digital readout said "Add 1.0L" and appeared to be right at the minimum gauge marking.
• I added exactly 500ml (5.5L total) and the gauge (in live read out mode) was bouncing between "ok" in the center of the gauge, and "add 0.5L" one notch below center.
• Started the engine, waited 10 mins, reading was "OK" and one notch above the center.
• Quick test drive, waited 10 mins, same result.

Conclusions:
WTF?

• The vehicle defintely appeared to have only had 3.5 (edit) kg, so perhaps ~4.2L of oil in it prior to my service, but:
  
  • No warnings were triggered.
  • Engine sounded and ran fine.
  • Manually checking the oil level before the service only said "Add 0.5L".
  
  
• The vehicle accepted 5.5L of new oil to achieve the correct level.
• The digital oil level sensor seems to have functioned completely correctly during the refilling phase (and now).

Importantly, there have been zero signs of oil leaks since re-owning the vehicle in the past year, at least externally or where I can see in the engine bay. I don't notice the vehicle blowing any smoke - so I really don't understand where 2L of oil went in the past 20000kms.

Help AULRO, what does (could) this mean??? What steps would you take next?

The car is going to an Indy next week for an overdue timing belt change, so obviously I will discuss with him, but is there anything else to check in the meantime?

[V8Ian]

Oil weighs less than 1kg/litre.

[75Vette]

Oil weighs less than 1kg/litre.

Fair point.

Even so, 3.5kg is at best 4.2 litres. That should be low enough to have triggered a warning, and is 1.3 to 1.7 litres less than "correct" amount.

[discomatt69]

Ah, for the love of God if only there was some form of long metal stick that could be poked into the sump somehow to give an accurate reading

[shack]

Ah, for the love of God if only there was some form of long metal stick that could be poked into the sump somehow to give an accurate reading

It would take years of R&D to get something like that working accurately.

Then an extra page would be required in the owners manual on how to open the bonnet (and what a bonnet is, depending on what country you are in).

It's never going to happen I'm sorry to report.

[Aussie Jeepster]

OK, dumb question!
If you get the correct oil level/quantity into the engine, can the breather tube be used to insert "a long metal rod" until it hits bottom?
Could said "long metal rod" then be marked where the oil level comes to?
I'm thinking a coat hanger or similar for the purpose, or does the breather tube not allow this.
I'm just thinking out loud here!
If not a coat hanger, what other item might work - surley someone else has tried something to confirm the electronic readout.

[Graeme]

It would take years of R&D to get something like that working accurately.

Then an extra page would be required in the owners manual on how to open the bonnet (and what a bonnet is, depending on what country you are in).

It's never going to happen I'm sorry to report.

LR must have been working on a solution for ages as the Ingenium engine has a dip-stick, although it appears that LR didn't quite get it right for the 2L version.

[DiscoJeffster]

OK, dumb question!
If you get the correct oil level/quantity into the engine, can the breather tube be used to insert "a long metal rod" until it hits bottom?
Could said "long metal rod" then be marked where the oil level comes to?
I'm thinking a coat hanger or similar for the purpose, or does the breather tube not allow this.
I'm just thinking out loud here!
If not a coat hanger, what other item might work - surley someone else has tried something to confirm the electronic readout.

You could use a bicycle brake cable theoretically as that would snake down the path of the extraction tube

[350RRC]

You could use a bicycle brake cable theoretically as that would snake down the path of the extraction tube

I have a 1999 Ford Courier (Mazda Bravo) ute, 2.6 petrol, that has a cable dipstick. 400mm from the bottom of it to the top of the insertion tube. Has a normal solid bit at the lower end with the levels stamped on, very nicely made.

There'd be plenty at the wreckers.

DL

[75Vette]

So.... I think we can all agree a dip stick would be nice.

Any actual thoughts on there only being ~4.2L of oil and no warnings triggering?

Presumably 4.2L is enough to run without low oil pressure?