Low Oil Pressure ZX 16V

VisaGTi16v · Unread post by **VisaGTi16v** » 21 May 2003, 21:04

Hi all,
My have quite worrying low oil pressure in my zx 16v. A few months back it used to sit around 5 out of 8 on the gauge when cold and idling, rising to 6 under load. When warm it would then sit around 3 and rise to 4 under load.
Now however when cold its on 3 at idle, rising to 4 under load. When warm it idles between 1-2 and under load about 3. This is quite close to 0, the other day when it was hot parked across a hill it was bordering on 0!
The oil level is fine, its not using any, there are no clatters or anything from the engine, its been regulary serviced etc. Could it be something simple like the oil pressure sensor being faulty or dirty contact and so the correct voltage is not getting down the wire to the dashboard gauge?
It has been like this vaguely since it was used for about 2 months with a dodgy thermostat leading to it always running cold and blocking up with mayonaise. This has been changed and after some long trips all the mayo has gone. Perhaps a service is required now?
regards
Darren Russell

Unread post by **Jon** » 21 May 2003, 21:12

had a similar thing with a BX16v once, oil pressure very low especially at idle.
Started with the simple things first and changed oil and filter. New filter used being Purflux. This improved matters dramatically.
In your case maybe either the filter is blocked, or the oil could be water contiminated, thus causing this problem.
Dunno whether anyone else has noticed it on this engine, but using Mobil 1 also seems to cause low oil presuure at idle.

VisaGTi16v · Unread post by **VisaGTi16v** » 21 May 2003, 21:55

It has been about 6000 miles since its last service as well. I will do the oil and filter and clean the lead/contact to the oil pressure gauge and see how it goes
cheers
Darren

jeremy · Unread post by **jeremy** » 21 May 2003, 22:35

I think this is a problem you shaould resolve sooner rather than later as from what I can see Citroen use oil pressure warning switches that operate in the region of .5 -.6 bar (about 10 psi for us imperialists!)
When Lucas made the pressure sensor switches they were notorious for failure and apparently the diaphragm inside used to go porous rendering the thing completely useless and those ones used to cost about £40 many years ago. (I had the wonderful experience of watching my jaguar one sink rapidly to zero while travelling down a fast dual cariageway! - fortunately that generation had a light as well - and that stayed out.)
Yours won't be made by Lucas - and may be more reliable and hopefully not so expensive.
I'm surprised the reading used to increase under load rather than with revs. Often if the bearings are worn the reading will drop under load as the crank moves to one side of its journals leaving a larger gap on the other side for the oil to leak out of.
Jeremy

VisaGTi16v · Unread post by **VisaGTi16v** » 22 May 2003, 19:16

sorry I meant revs

I will do the oil/filter change then move onto the switch if its not fixed
cheers

tecw1979 · Unread post by **tecw1979** » 16 Jul 2003, 04:25

i did a very silly thing that caused erratic pressure reading on my 16v mi16 engine (bx 16v) . i mashed up the oil cooler in a head on collision and decided as i couldnt find one id weld the pipes from under the filter up. so i did. only to find the unit wouldn fit at the correct angle anymore bcos of te way id welded the pipes, they hit the air con mounts! the pressure from then on would build up in steps on start up taking abt 3 staps and 30 seconds to reach abt 6-8 on the guage!this is fixed now though!!!

adrianeaton · Unread post by **adrianeaton** » 17 Jul 2003, 14:20

<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by Jon</i>

had a similar thing with a BX16v once, oil pressure very low especially at idle.
Dunno whether anyone else has noticed it on this engine, but using Mobil 1 also seems to cause low oil presuure at idle.
<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">
My BX 16V has always shown relatively low oil pressure at idle, especially when warm.
The gauges on these engines are useless - over a period of time it went from reading correctly, to recording no pressure at idle and 4.5bar on the move, and then flicking up and down at random - seeing it drop to zero on the M25 the 1st time was quite scary! The oil warning light has NEVER come on. I had the wiring checked at the last service and a replacement sender unit has proved more reliable - I now get 6-8 bar when cold and moving. Usually hits 8 bar if the lights are on!!!
Apparently the majority of faults are down to failures in the wiring behind the dashboard giving intermittant readings.
Anybody else noticed that oil pressure 'goes up' with electrical load on a BX?!
On Jon's second point - depends what grade of Mobil 1 you use. The 0W40 is way too thin for the engine, the 10W60 is spot on. I rang their technical service line some time ago to check whether it was suitable and that was what they recommended.
Cheers
Adrian

Unread post by **Jon** » 17 Jul 2003, 14:42

Yes, too right about the 0w40. Put some of that in a GSA once and the oil pressure light was on at tickover! Plus, the engine leaked even more oil than GSA's normally do.
The Total Quartz 9000 fully synthetic 5W40 seems OK, use that in the Berlingo and after I first put it in the thing felt a whole lot smoother and more powerful (if that term can be applied to a 71HP diesel).
In fact, on the new generation DW8 and HDi engines semi or fully synthetic should be used anyway.