low oil pressure at idle

[EV1LXR8]

when my xr8 s1 warms up to running temp and i pull up to a stop the oil pressure drops down allmost to the red i just did a new filter and oil valvoline XLD premium 20w-50 i take off again and the pressure will build up to normal again, i have been looking at the Z89A filter, will this fix my problem? i have a z9 in there at the moment, it drops pressure so fasr sometimes that it warns me of low oil (red marker it beeps 3 times at me) can anyone help

[mik]

z89a is the listed filter for the v8, i`m unsure what the difference is between the two(z9) , a mate has an au fairmont v8, his also has the low oil pressure at idle ,although it does`nt seem to affect it, it would be interesting to see an aftermarket oil pressure gauge hooked up to see what the pressure really is.

[GK]

IIRC, the Z89a is smaller keeping more oil available in the sump.

The capacity of the Z9 is 600mls or so.

GK

[mik]

Originally Posted by GK

IIRC, the Z89a is smaller keeping more oil available in the sump.

The capacity of the Z9 is 600mls or so.

GK

aaah ok, thanks GK.

[CRAIGAU3220]

Originally Posted by GK

IIRC, the Z89a is smaller keeping more oil available in the sump.

The capacity of the Z9 is 600mls or so.

GK

Thats funny.....The Z89 is for the the 220kw & 250KW versions which run a oil cooler.

[KR1STO]

Originally Posted by CRAIGAU3220

Thats funny.....The Z89 is for the the 220kw & 250KW versions which run a oil cooler.

Yep, It's used because the Z9 wont fit when the oil cooler is fitted...

[GK]

Some good extra discussion here.

Originally Posted by Cam

AFAIK The AU gauges never move, unless there is NO oil pressure at all.. Although never sat in an AUI XR8, so may be different..
My guess, Either that or the sender is rooted / the connection is loose, has come off, or is full of crap.. The same has happened to me..

Kristo is on the money, the S1 had the proper gauge.
Correct me if I’m amiss here, but the S2-3 items work like an on/off deal, where the gauge shows you’ve got correct pressure (meaning some pressure) or none!
Cam, if your gauge shows nothing, then I reckon it’s a loose wire or otherwise as you’ve suggested.

Originally Posted by CRAIGAU3220

Thats funny.....The Z89 is for the the 220kw & 250KW versions which run a oil cooler.

Okay, never heard that connection being discussed before. I've only heard general talk about V8 guys going from Z9 to Z89 to sure up pressure. That's good info. JC has a 220, I wonder what filter is on his? And also whether he's got an oil cooler running?

So then, if the OP has a Z9 on his V8, and if Craig and Kristo are correct on the reasons for the Z89 over the Z9, then perhaps it’s just for him a matter of having oil a little too thick for winter? He does have pressure, but it drops off on idle.

Here's his post again.

Originally Posted by EV1LXR8

when my xr8 s1 warms up to running temp and i pull up to a stop the oil pressure drops down allmost to the red i just did a new filter and oil valvoline XLD premium 20w-50 i take off again and the pressure will build up to normal again, i have been looking at the Z89A filter, will this fix my problem? i have a z9 in there at the moment, it drops pressure so fasr sometimes that it warns me of low oil (red marker it beeps 3 times at me) can anyone help

So it's a S1 therefore with no cooler.

EVILXR8, when you went the 20w/50, is that the same viscosity you have used previously? Same brand?

If you upped the viscosity and have always run Z9 filters, then I'd assume it's the oil. If you've run the same filter and oil (viscosity and brand) as previous, then you've probably got another problem.

Hope my reasoning here makes sense?

GK

[Mr Hardware]

i love when you buy a z9 and it says falcon 1960-2005

funny thing with the z9's is they come with their own post code they're that big

[Cam]

AFAIK The AU gauges never move, unless there is NO oil pressure at all.. Although never sat in an AUI XR8, so may be different..

My guess, Either that or the sender is rooted / the connection is loose, has come off, or is full of crap.. The same has happened to me..

[KR1STO]

Series one was a proper gauge Cam..

[Cam]

Thanks Kristo, wasn't sure when the "real" gauges stopped..

[KR1STO]

no worries mate..

[mik]

how many K`s has your engine got on it Ev1lXr8?

[EV1LXR8]

260xxx on the clock, i had 15w 40 for my last batch of oil, (put in by mech) i can fit a z9 in (just). not sure if it has an oil cooler. its an ex chaser so it got added bits and peices. different brand filter and oil
here are a few pics not sure wawt a cooler looks like



this last pic is some sorrta cooler in front of the radiator not sure wat its for is it an oil cooler?


thanks for the help also guys

[GK]

Originally Posted by EV1LXR8

260xxx on the clock, i had 15w 40 for my last batch of oil, (put in by mech) i can fit a z9 in (just). not sure if it has an oil cooler. its an ex chaser so it got added bits and peices. different brand filter and oil
here are a few pics not sure wawt a cooler looks like



this last pic is some sorrta cooler in front of the radiator not sure wat its for is it an oil cooler?


thanks for the help also guys

I'd say drop the oil and go back to 15w/40 or a 15w/50 oil.

GK

[Tickford Kid]

Series 1 AU XR8's had a problem the earth on the engine that made the oil pressure gauge play up.
It has been a long time I owned an XR8 that done this.
Do a search about it. There was a technical service bulletin about it.
The problem isn't with the filter.

[Cam]

Originally Posted by TS 50

Series 1 AU XR8's had a problem the earth on the engine that made the oil pressure gauge play up.
It has been a long time I owned an XR8 that done this.
Do a search about it. There was a technical service bulletin about it.
The problem isn't with the filter.

Yeah actually, now you say it i remember reading it. rep+

[GK]

Originally Posted by TS 50

Series 1 AU XR8's had a problem the earth on the engine that made the oil pressure gauge play up.
It has been a long time I owned an XR8 that done this.
Do a search about it. There was a technical service bulletin about it.
The problem isn't with the filter.

Certainly worth checking out for sure.

Remember though, that his oil pressure issue only started after using a thicker grade oil.

GK

[EV1LXR8]

i red in an old post that you can put an extra 500ml of oil in and that apparently help with the pressure, any dangers to this? it was doin it b4 the oil change but no where near as much as its doin now, also i brought a z89 filter so waiting for that to arrive to put it in, ill check out that tech post, cheers

[GK]

Originally Posted by EV1LXR8

i red in an old post that you can put an extra 500ml of oil in and that apparently help with the pressure, any dangers to this? it was doin it b4 the oil change but no where near as much as its doin now, also i brought a z89 filter so waiting for that to arrive to put it in, ill check out that tech post, cheers

Okay, so thinner oil, checking your oil pressure sender and the smaller filter should see you through! LOL!

All the best with it.

GK

[phil ford]

This is an old thread, but did anyone ever resolve this issue?

I have exactly the same problem, same car xr8 au1, been doing it for nearly 12 months now and engine still going fine. My mechanic has no idea; replaced oil switch; still doing it.

Frustrates the hell out of me.

[AUFanboy]

It's most likely an earthing issue with the gauges. Add a nice fat ground cable from one of the alternator mount bolts to somewhere solid on the car's body. You can also go to the negative battery terminal, but it's better to go to the body because most of the car's electrics (including instrument cluster) ground to the body, then the current has to get back to the alternator casing (which is the ultimate ground when the engine is running). Supercheap Auto has some nice cables with pre-crimped lugs.