TU5JP4 oil dilution issues

This is the Forum for all your Citroen Technical Questions, Problems or Advice.

Moderator: RichardW

maxxo
Posts: 40
Joined: 21 Aug 2019, 01:00

TU5JP4 oil dilution issues

Post by maxxo »

Hi all,

helping a family member out with their picasso which has the tu5jp4 1.6 16v engine and is suffering major issues at the moment

so just over a month ago i heard it ticking and knocking at idle, so we checked the oil and saw it massively overfilled and reeked of petrol, so i did a quick oil change which mostly quietened it down....

however i went round their house yesterday and just happened to check the oil, which was alright however upon removing the filler cap it stunk of fuel again and it's not running/sounding right, it also has an oil change but i believe the sump plug needs tightening up slightly

do these engines suffer with dilution issues? and is there anything else to check which could be causing this?

also the noise it's making at the moment sounds like the injectors firing but much much louder with a quiet dull knocking sound and at idle the engine does move around a bit almost like it's misfiring which it didn't used to do........however there is no warning lights illuminated but i haven't had the chance to plug it into lexia

411514
Donor 2017
Posts: 417
Joined: 14 Dec 2010, 16:26
x 38

Re: TU5JP4 oil dilution issues

Post by 411514 »

I've had a couple of these engines, and they aren't the best.

Ticking at idle isn't necessarily abnormal, they are a bit ticky, so as long as it isn't excessive, probably not an issue. Knocking is abnormal though.

As far as I know, no known oil dilution issues. Probably unlikely that it was petrol in the oil that made it appear overfilled.

They do usually stink of petrol, it was a problem we found with both. We tended to find that when it cold, come to a stop, and it stank of petrol. I think I decided it was probably a blocked purge line/faulty valve to the charcoal canister, but I never bothered fixing it. The purge line/canister absorbs petrol fumes, I think from from the crankcase, but unsure on this (could absorb from the tank/lines). Either way, likely that the petrol fumes you are smelling is not petrol in the oil, but just faulty/rubbish purge system, which wouldn't be the cause of the poor running.

Re the poor running, more than likely in my experience of both engines we had, this will be the coil pack. I tended to find they only lasted approx 50k miles. Poor sparking would make the petrol stink worse, as there would be more unburnt fuel in exhaust. I would try replacing the coilpack, which isn't too expensive - carparts4less.com has them for not much over £50.

Re the sump plug, be careful over-tightening, its a thin pressed aluminium sump, and the threads strip if you even look at them funny. I had to helicoil both of ours due to stripped threads.

They also seem very sensitive to fuel quality, I left one sitting around with old fuel in it for a few months, and it was misfiring all over the shop when I next started it, which was remedied with new fuel.

wheeler
Posts: 4383
Joined: 21 Sep 2002, 19:07
x 164

Re: TU5JP4 oil dilution issues

Post by wheeler »

Most petrol engines will stink of fuel when the oil cap is removed so wouldn't think that unusual

Might be worth doing a compression test on the engine. Although the tech bulletin relates to oil consumption issues It could also cause dilution issues, especially if its used for very short journeys.

From Citroen Technical Bulletin:
Vehicles / Engines: C2 - C3 – C4 – Picasso - Berlingo Moteur TU5JP4 (NFU)

Customer complaint: Excessive oil consumption.

Diagnosis: Premature wearing of the piston rings.

Cause: The origin of this defect is not yet identified. The majority of the cases all come from one period of manufacture which is between September - October 2005.
The exact cause is still under investigation.

maxxo
Posts: 40
Joined: 21 Aug 2019, 01:00

Re: TU5JP4 oil dilution issues

Post by maxxo »

Thanks for the replies

did some more investigating today so it seems the oil level is increasing again......great! and the oil which is just over a month old is absolutely filthy

Oil leak was simple to sort i got half a turn on the sump plug so that was sorted

it strikes me as unusual for a coil pack to have failed to the point i can notice it not running right yet not bring a warning light/fault code up

i've also noticed the whole car feels quite poorly built compared to my 05 picasso which is a shame

maxxo
Posts: 40
Joined: 21 Aug 2019, 01:00

Re: TU5JP4 oil dilution issues

Post by maxxo »



THis is how it was sounding today, not too bad actually but listening to the video closely you can hear irregularities in how it runs