DS low engine oil pressure

[palyasm]

I was looking at a DSpecial the other day and the owner mentioned that the oil pressure light is flickering. I noticed that with the engine freshly stopped there was no sound of oil draining back to the sump. Looking through the filler neck there was no oil to the rockers. He has just confirmed that with the rocker cover off there is only minimal oil weeping from the exhaust rockers, nothing on the inlet.

I have worked on many D engines and have not seen major low oil pressure before. He tells me the engine has been rebuilt, and that this issue has been there all the time (!?!), so I'm thinking the bearings fitted must be the wrong size. Unlikely to be the oil pump / relief valve?

I haven't rebuilt a D engine for years, and I'm trying to remember where other likely pressure leaks might occur...

Any good ideas welcome

 

[DoubleChevron]

Oil filter triangles not lined up evenly enough .........

Oh I forgot to mention ..... check the oil pressure switch as a matter of urgency.... I've had them start leaking profusely in a CX... to the point where between the light coming on .... and doing a Uturn and heading back home (3 minutes down the road) ... I dumped 3.5litres out of the sump in that 3 minute drive

bugger all oiling to the top end seems to be a feature of DS engines

 

[palyasm]

I think the triangles on the filter housing/sump is mainly about cornering, etc so the main pick-up point is the least likely to suck air when the oil sloshes around? running the engine stationary with a full sump, I don't think this would cause low oil pressure?

missing o ring in the filter housing - but the end of the pump should still pick up oil with a full sump?

 

[faulksy]

This might be stating the obvious but was there enough oil in the engine? If you can, take out the pressure switch and replace it with a guage to see what pressure you've actually got.

The pipe that feeds oil from the block to the head just behind the water pump on the inlet side might be crushed or blocked but that wouldn't cause the oil pressure light to come on. The oil pump cams can wear out or as Shane said, the triangles are out of alignment.

Is it possible that the oil pump isn't sealed to the block so it's just moving oil around the sump?

 

[David S]

Assuming the sump is full (and it's not electrical), the oil filter is the obvious place to start. Two helpful references that highlight some possible problems arising from missing parts and incorrect assembly:

Citroen DS oil filter change – Classic Citroën DS

Posts about Citroen DS oil filter change written by classiccitroen

citroenclassics.wordpress.com

Caution! Losing a part when changing oil filter may mean an engine rebuild!

I have seen too many of these mistakes now that I feel compelled to warn anyone who changes their own Citroen DS or ID oil and filter about it. There is a part which the oil filter sits on, a kind …

citroenclassics.wordpress.com

 

[Budge]

I would start with the simplest and check the oil level. And then check the oil pressure switch.

A look at the diagram in manual 814 suggests the oil first goes to the inlet rocker shafts and so inlet valves) before it goes to the exhaust valves. If oil is flowing to the exhaust valves, then that means it must surely be flowing through the inlet shaft and so also to the inlet valves?

Should one expect to see a steady flow of oil from the holes in the rockers or just the occasional spit?

 

[David S]

One could disconnect the pipe feeding the head, crank it and see if a good flow is ejected into a clean jar.

 

[palyasm]

Oil level was my first question, and yes it is full. I don't have the car in my workshop, so can't check the switch, however you can usually see the oil drooling out of the rockers lubricating the pushrods and valve stems, looking through the filler. It is also normal to hear the very obvious trickling as the oil drains from the valve gear back to the sump when the engine is stopped. these conditions are not present.

I have a spare oil pump here, so I'll have a look whether a blockage could be checked for in situ...

 

[palyasm]

The blog posted above re the rubber washer - looking at the pump I have here there is no way that washer could disappear entirely into the pump unless the rubber got torn, as it encircles the central filter retaining bolt. So if this is his problem the washer should be easy to see with the filter removed.

Interestingly, the very part mentioned in the warning is missing from the assembly I just looked at in the workshop... I have no memory where the pump came from. I assume I didn't forget to refit it...

 

[PeterMol]

I think the triangles on the filter housing/sump is mainly about cornering, etc so the main pick-up point is the least likely to suck air when the oil sloshes around? running the engine stationary with a full sump, I don't think this would cause low oil pressure?

missing o ring in the filter housing - but the end of the pump should still pick up oil with a full sump?

Not correct. If the triangles do t align oil feed is starved. Take out the filter housing and you will see the slot that allows the oil flow. Seizing the engine is a short term proposition if they are not aligned

 

[PeterJ]

After a rebuild on a DS I had a flickering oil pressure light but only at idle. A few extra revs would extinguish the light. It did turn out to the the wrong size main bearings which were then replaced. I'd second the idea of installing a pressure gauge

 

[palyasm]

Thanks for all the replies - the owner removed the oil filter and although all the parts were in place, the top rubber washer normally glued to the element had come partially adrift and was at least partially blocking the suction hole in the pump/filter housing.
He reports there is now plenty of oil flooding the valve gear and oil drain-back is audible on switch off.
The car has had a few KMs since the rebuild, and appears to be fine, so clearly it was getting just enough past the blockage...
Certainly a cheaper fix than investigating crank journals/bearings, etc!