Thread: Td5 major oil loss - what just happened?

10 bar is 150 psi, with that sort of oil pressure, like 3 times whats normal I'd have thought you'd been running on oil fed past the turbo seal and into the inlet tract & noticed smoke & over revving before any catastrophic event.

My guess is the oil pressure was fine but the madman sensor was faulty

The relief valve should have blown first.

Who does your oil changes, My guess is the bolts on the rotor housing were over tightened & stripped, just waiting to blow off ???

If you genuinely had over 140 PSI oil pressure I would of thought that the Oil Cooler would have burst leading to oil in the coolant and major coolant loss.
I am sorry for your situation hopefully it was a simple as the threads being stripped mine have helicoils in them because they too were stripped by over zealous mechanics.

Pics?

I can buy 140psi not pushing out the turbo seals as the turbo seals dont see full working oil pressure as the drain is a lot larger than the supply.

Im going to guess that the drain from the rotor housing got blocked stopping it from draining, 40 psi over the area that the housing covers would easily pull the 2 m8s out of the ally.

but excluding that..

the oil cooler is drain to sump so in theory shouldnt see any working pressure as it offers little to no restriction to flow, the rotor filter does so lets play with this scenario.
(edit its full pressure and cools the oil Before it goes into the galleries and not the bleed off oil from the filter, had my head in the wrong department)


1. the relief valve has jammed closed
2. the oil pressure being fed into the rotor filter has skyrocketed (its skyrocketed everywhere but in this case the rotor has been the component thats failed)
3. the filter has overspun and stalled onto the shaft (or its been completely blocked from not being changed)
4. the pressure has built inside the rotor filter untill its burst and the stored energy has smacked the filter housing off.

Ok Dave thanks. Well I don't have the knowledge to argue against any of that, and wouldn't argue anyway, after all I'm after opinions, and that all sounds reasonable.

For what it's worth here's the only picture I took it's of the stripped thread (well stripped housing in the thread of the rotor filter cover) both bolts were the same. Like I said it was resting on the rotor filter but 90 deg. out of place when I found it. The rest was, well an oily Td5, not very photogenic! The rotor filter was intact, undamaged and span freely when I whizzed it round with my hand.

I changed the filter out about 3000km ago, along with oil change and usual service (about every 6K all filters and oil) and I torqued the retaining bolts up to spec using a torque wrench as was aware that it was somewhat vulnerable to over tightening.

Attachment 41301

I had some oil loss since then but had though it was down to a leaky rocker cover gasket that I had been meaning to change, it may have been getting worse very recently (judging by the larger than usual oil stain on the driveway I can now see in it's absence). The day before the incident I had topped it back up to full on the dip stick (took about quarter liter).

Now I think about it while back after a service I remember an un explained oil leak (possible discharge) from a similar area (passenger side of engine). Would this be where the relief valve is?

It's at the garage now, they'll get back to me tomorrow (I hope) and let me know what they reckon, still wondering what the cause could have been and what the damage may be.

It was running at about 2.3 bar oil pressure most of the time - which I took to be normal. Although this would drop to 0.9 bar when I came to a standstill triggering the low pressure alarm. I thought nothing of this.

Are there any things that I should ask the garage to look at in particular? All this is a bit beyond my comfort zone.

Cheers for your input.

Ian.

the relief valve should be part of the pump setup.... (going to have to have a dig through the books, sometimes it forms part of the gallery the pump bolts to and sometimes part of the filter assembly)


check the return drain for the rotor filter housing, if thats clogged theres your culprit.

else Id suspect that youve had a combo of the bolts being done up over enthusiastically one time too many and its finally let go combined with a spike reading when the cap blew off... Ive seen some interesting results from diesels when a contaminant in the oil has spontaneously ignited in the sump...

Thanks Dave. Any info on the releif valve, operation, location would be of benifit, if not just for future referance. Is there any way of (manually)checking it's operation say at the service interval? I honestly have never heard it ever referred to.

If it was near the filter housing would explain the mystery oil leak I had some time ago.

I can't think how it would have got any contamination in the oil to make it block though.

Fingers crossed for the report from the gararge now. Although the longer it takes the more I fear.

Ian.

The relief valve is part of the pump assembly, the only way to check it is by operating the pump and measuring the pressure it puts out. the easiest way of doing this is with a gauge in the oil pressure senders hole and running the engine.

The oil cooler is a full pressure item. and deals with the full pressure of the system when the oil temperature is high enough...

FYI

TD5 Very high oil pressure - SA 4x4 Community Forum