UKC

My Peugeot Partner van has been having some issues over recent months - the problems have been with his oil pressure (or so the warning light suggests).

The fault is intermittent and is as follows:

Whilst driving the oil warning light comes on (and hence the stop light).
When this happens the engine sound changes, it goes from a nice normal purr, to something more rattly with more of a "chug chug chug" sound.
The van still drives perfectly but the sound is quite noticeable and the warning light stays on. You basically want to stop (and I do).

It's happened three times so far:

1st time was when driving from Nottingham to Skipton and it happened next to Caley Crag - so about an 1 hour 15 minutes into a drive. We left it for 20 minutes and decided to set off with everything sounding okay again. The warning light came back on and engine sounded horrible again after about 15 minutes.

I called my breakdown cover and they came for a look. They checked the oil which was fine (i.e. it was still full) - he topped it up a little anyway to be on the safe side. Then he drove behind us (after the van had been off for an hour) for the last 20 minutes of our journey and there were no problems so he left.

2nd time was on the way from Skipton to London and it happened at Bishops Stortford - so about an 2 hour 30 minutes into a drive. It was late and I couldn't be bothered waiting and risking the last hour of drive so I got towed to London.

3rd time was on the way from London to Cambridge and it happened at Bishops Stortford again - so about 1 hour into a drive. I didn't need to be there until the next morning so I had about 3 hours sleep in the van at the services (and got a parking ticket) and it then drove perfectly to Cambridge, and then Skipton.

These three occurrences happened over the course of about 1,500 miles with lots of short and long (up to 3 hour) drives in between.

The similarities between the issues were that I had been driving over an hour each time, I was travelling about 60mph and due to the roads I'd been sitting in the same gear for a while. The other similarity is that if left until the engine had cooled (1 hour plus), it seemed to be okay for a while afterwards.

After the first occurrence, the van has spent a day in the garage which included an hour drive by the owner and a 2 hours of poking around the engine. He couldn't find anything wrong and said to bring it back if it happened again which I never got chance to.

The van is due a service but the garage said not to do this straight away incase it ends up being £200 wasted.

So, great minds of UKC. Have you ever heard of anything like this happening before? Or do you have any idea what it might be?

Something that would cause an oil pressure warning and an odd sounding engine at the same time, which then reverts back to normal once it's cooled. I am due to get a company car soon so I was planning to sell the van but it would be nice to try and fix it first.



EDIT - my thought is to get x/y/z changed and start using it properly again and see if it seems to have fixed anything,,,

In reply to James Malloch:

Not an expert, but something cheap to try on this thread http://www.honestjohn.co.uk/forum/post/?t=74428

In reply to James Malloch:

I'd first change the oil pressure switch. This seems most likely at this stage but the garage must have already done this surely?
When the pressure switch is triggered I'm guessing it lights your dash warning light and sends a signal to the ecu, the ecu then switching to limp home mode as it thinks there is low pressure.

In reply to James Malloch:

Have you changed the oil and filter during this period?

In reply to James Malloch:

The garage didn't change anything. It's a decent guy running it who has always done the van since I bought it - always don a thorough job so I would have thought he would check any obvious things...

When you say "limp home mode" - would this affect the sound of the engine?

And the oil has been changed, but not the filter. That's one of the things I was going to do in the next week or so.

In reply to James Malloch:

How old is the van? Does it have OBDII? If so, are there any fault codes? If there are no codes when all is well, try checking for codes when the light is on, i.e. when stationary but before switching off. An ODB reader that works with a smartphone can be had on ebay for about £3.

In reply to Jack B:

It's 2007, diesel and has 120k on it.

No idea abut OBDII - I guess it would be in an obvious place to see if so?

In reply to James Malloch:

I suspect the change in sound is because oil pressure has dropped (hence the light) and its running on low pressure and therefore not getting the necessary lubrication round the engine.

As above, have you tried changing oil and filter? Secondly, could be some sludge/etc in the sump that partially blocks the oil pick up pipe causing low pressure. After you've left it a while, it may dislodge itself and then be fine. Try dropping th sump and see what's in there when you change the oil.

In reply to Oli:

I would go for it being an actual drop in pressure rather than a faulty sensor too.
Never had a vehicle clatter and clunk in limp home mode.
Most likely a blockage in the oil pickup pipe.

In reply to James Malloch:

Since your car was built 2007 it will have OBDII. The socket into which you plug the diagnostics will be somewhere under the drivers side of dash. If you have had a caution / stop light on, the engine management computer should have stored a fault code which will help in diagnosing where the problem lies UNLESS someone has disconnected the battery or pulled a fuse since the fault occurred. Google ODBII for your vehicle. It will tell you where the socket is. Any half way decent auto electrician should have an OBDII code reader, although there are standard ODBII fault codes common to all vehicles and specific OBDII codes to each manufacturer / vehicle, so it does depend exactly what your fault is....

In reply to James Malloch:

A few possibilities spring to mind, the most obvious, a dodgy switch is ruled out by the change in sound which is consistent with a drop in oil pressure.

Given it occurs well after the oil should have got hot it's probably not just the oil thinning out and the regulator unable to cope. Is it possible there's something causing the engine/oil temp to rise in the phase of the journey you've had the problems, going up hill slowly, significant tail wind (and failed fan), radiator full of flys and only just working etc?

The next thought is the oil pick-up getting blocked or sucking air/foam. If you have a steel sump, could it be dented? Other possibilities are a cracked pipe or o-ring on the oil suction system, sludge in the sump, blocked filter (these have safety bypass valves built in so unlikely), foaming oil (typically a turbo vehicle issue).

Finally there's the oil pressure regulator, it could be sticking open if the oil has got dirty (old failed oil filter).

I'd get the oil and filter(s) changed in accordance with the service manual and make sure the rad/oli-cooler are clean, I suspect it might sort itself out once you have. At worst you lose a fill of oil should you have to go in for a second look at the pick-up, strainer and pressure regulator.

jk

In reply to James Malloch:

Many thanks for all the really helpful replies - lots of thing I wouldn't have thought about!

I'll have a proper look through them at lunch and see if I can find somewhere to book it in this week. I'm not sure I'm up to doing it all myself...

Paul - I'll have a look for an OBDII reader too - no harm in ordering one if they're only a couple of quid.

In reply to James Malloch:

Just to suggest the same as above really. First port of call should be to read the fault codes. Modern cars are usually very good at reporting problems.

I agree it sounds like a genuine drop in oil pressure, rather than just a duff pressure sensor causing a dash light to come on. This is could be mechanical in nature (how is the oil pump driven? Belt, chain or electric motor?), or might be related to another sensor problem and the ECU regulating oil pressure incorrectly (get the fault codes checked/DIY).

Otherwise an intermittent blockage could be starving the oil pickup and/or pump. When was the oil/filter last changed? If more than a few thousand miles it's worth changing it anway just to rule it out. If you get a garage to do it rather than DIY (which is usually very easy BTW), make sure they drain the oil through the sump plug, rather than sucking it out the top with a hose. Has anything else gone wrong in previous years that could have left broken bits in the sump? I'm not familiar with the engine, but perhaps a broken chain guide/tensioner - any problem with timing chain/belt in the past?

Last thought, what does it sound like when you first turn it on from cold? Do you get the rattly low oil pressure sound for a few seconds, or does it run sweet as soon as you turn the key? What about when hot?