[modern] Oil pressure

Disused Categories Modern
1

Hello all lovers !

Can Sone tell me what is the 'normal oil pressure for the next rpms
Cold Idle, warm idle, cold 1500rpms warm 1500rpms,
I checked mine and found 2bar for idle and 3.9bar for 1500rpms at idle cold,
if the engine is warmed, the oil pressure drop down dramatically to 0
(linked to the noise
-> one conn rod or main crankshaft bearing worn)

(all these infos are in the archive i know…)

Please to give me your input
Thanks

Nicolas Huber
@Nicolas_Huber

2

Nicolas, my car has 7 bar at cold idle, 8 bar at speed when cold, 7 bar at
speed when warm and about 6 bar at warm idle. The 88 and 89 cars with digital
guages had problems with the sending units going bad and causing the guages
to drop tp 0 when hot but they usually would come back up to show pressure
again shortly. If you have worn main bearings they will cause a true low oil
pressure. If you are sure your guage is correct and your engine is truely
running 0 oil pressure when hot, it should not be driven. You will do more
damage to it than you have now. Have an external pressure guage installed and
check to see if its the sending unit or a true no or low oil pressure. Con
rod bearings won’t cause low pressure but mains will.
Jim Moore(88 XJ40)

3

Thanks for your input Jim
I don’t think I’m crazy (Well, I own a jag…)
I won’t drive it until all is ok ! (but it’s hard not to drive it !!!)This
is a beloved car !

Cheers
Nicolas-----Original Message-----
From: Gasshauler@aol.com Gasshauler@aol.com
To: @Nicolas_Huber <@Nicolas_Huber>; modern@jag-lovers.org
modern@jag-lovers.org
Date: Monday, May 31, 1999 2:42 PM
Subject: Re: [modern] Oil pressure

Nicolas, my car has 7 bar at cold idle, 8 bar at speed when cold, 7 bar at
speed when warm and about 6 bar at warm idle. The 88 and 89 cars with
digital
guages had problems with the sending units going bad and causing the guages
to drop tp 0 when hot but they usually would come back up to show pressure
again shortly. If you have worn main bearings they will cause a true low
oil
pressure. If you are sure your guage is correct and your engine is truely
running 0 oil pressure when hot, it should not be driven. You will do more
damage to it than you have now. Have an external pressure guage installed
and
check to see if its the sending unit or a true no or low oil pressure. Con
rod bearings won’t cause low pressure but mains will.
Jim Moore(88 XJ40

4

Nicolas

The oil pressure sender is notoriously unreliable. I got fed up of mine
doing this and had it replaced. The replacement sender doesn’t even attempt
to register oil pressure, it is just a pressure switch and a resistor - so
long as there is enough pressure to trip the switch the gauge stays right in
the middle. The sender cannot be repaired.

Kevin
93 XJ6 44K
65 IIA 109" SW
56 I 107" SW-----Original Message-----
From: owner-modern@jag-lovers.org [mailto:owner-modern@jag-lovers.org]On
Behalf Of Nicolas Huber
Sent: Monday, May 31, 1999 1:22 AM
To: modern@jag-lovers.org
Subject: [modern] Oil pressure

Hello all lovers !

Can Sone tell me what is the 'normal oil pressure for the next rpms
Cold Idle, warm idle, cold 1500rpms warm 1500rpms,
I checked mine and found 2bar for idle and 3.9bar for 1500rpms at idle cold,
if the engine is warmed, the oil pressure drop down dramatically to 0
(linked to the noise
-> one conn rod or main crankshaft bearing worn)

(all these infos are in the archive i know…)

Please to give me your input
Thanks

Nicolas Huber
nhuber@ctp.com

5

Hello to all; I have a 93 xj6vdp with 4.0. The oil pressure is usually ok
40 plus at idle until it gets warm then dropping down to 20 or so. Today,
while stooped at a stoplight, we noticed the red light blinking on and off,
and the pressure was almost at the bottom! I’m using Castrol GTX 10w40. The
coolant temp. never got above normal, and the oil level is spot on. So
what’s the deal? Weak oil pump? Wrong viscosity?
Roger D. Simons
rogsimons@att.net

6

Most likely just a bad oil sending unit. However you had better verify
just incase its something more serious.4/13/02 5:07:57 PM, “Roger Simons” rogsimons@worldnet.att.net wrote:

Hello to all; I have a 93 xj6vdp with 4.0. The oil pressure is usually ok
40 plus at idle until it gets warm then dropping down to 20 or so. Today,
while stooped at a stoplight, we noticed the red light blinking on and off,
and the pressure was almost at the bottom! I’m using Castrol GTX 10w40. The
coolant temp. never got above normal, and the oil level is spot on. So
what’s the deal? Weak oil pump? Wrong viscosity?
Roger D. Simons
rogsimons@att.net

7

Roger,
Agree with David… probably a bad sending unit. I had the same problem with
the original sender, replaced it with the “new??” of-off unit (about $8.00).
This sender will read either mid-gauge (on) or flat (off). If “on”,; your
engine has pressure with-in spec.; “off”, probably a problem. Highly
recommended… puts all of that pressure gauge angst right out the Jag
window.

Mike
95 XJR----- Original Message -----
From: “David Boarder” dboarder@sympatico.ca
To: modern@jag-lovers.org
Sent: Saturday, April 13, 2002 9:22 PM
Subject: Re: [modern] Oil pressure

Most likely just a bad oil sending unit. However you had better verify
just incase its something more serious.

4/13/02 5:07:57 PM, “Roger Simons” rogsimons@worldnet.att.net wrote:

Hello to all; I have a 93 xj6vdp with 4.0. The oil pressure is usually
ok
40 plus at idle until it gets warm then dropping down to 20 or so.
Today,
while stooped at a stoplight, we noticed the red light blinking on and
off,
and the pressure was almost at the bottom! I’m using Castrol GTX 10w40.
The
coolant temp. never got above normal, and the oil level is spot on. So
what’s the deal? Weak oil pump? Wrong viscosity?
Roger D. Simons
rogsimons@att.net

8

I have to strongly disagree with that statement. The new style on/off sending unit essentially turns you rgauge into an
expensive idiot light. If its on (mid scale) it means you have some pressure not necessarily in spec. If its off you could be
in serious trouble (assuming its working). You could for instance be humming along at high speed with only 10lb of oil
pressure and it would still be reading mid range. Its a bad way to compensate for a poor sending unit. I’d rather keep
the original function and change it every five years or so.4/13/02 11:25:15 PM, “mwarne” mwarne@wmis.net wrote:

Roger,
Agree with David… probably a bad sending unit. I had the same problem with
the original sender, replaced it with the “new??” of-off unit (about $8.00).
This sender will read either mid-gauge (on) or flat (off). If “on”,; your
engine has pressure with-in spec.; “off”, probably a problem. Highly
recommended… puts all of that pressure gauge angst right out the Jag
window.

Mike
95 XJR
----- Original Message -----
From: “David Boarder” <@David_Boarder>
To: modern@jag-lovers.org
Sent: Saturday, April 13, 2002 9:22 PM
Subject: Re: [modern] Oil pressure

Most likely just a bad oil sending unit. However you had better verify
just incase its something more serious.

4/13/02 5:07:57 PM, “Roger Simons” rogsimons@worldnet.att.net wrote:

Hello to all; I have a 93 xj6vdp with 4.0. The oil pressure is usually
ok
40 plus at idle until it gets warm then dropping down to 20 or so.
Today,
while stooped at a stoplight, we noticed the red light blinking on and
off,
and the pressure was almost at the bottom! I’m using Castrol GTX 10w40.
The
coolant temp. never got above normal, and the oil level is spot on. So
what’s the deal? Weak oil pump? Wrong viscosity?
Roger D. Simons
rogsimons@att.net