OIl Pressure

JamesW · Post by **JamesW** » Wed Mar 12, 2008 9:22 pm

Anyone know what the oil pressure is supposed to be for a NA 1.6 while idling?

I've got somewhere b/t 15-18 lbs. at idle after driving for about an hour. Its over 100 lbs. when I start the engine up if its cold.

My oil light seems to come on if its under about 25 psi.

Is that normal??? It drives me crazy. And I hope its not doing any harm to the engine.

Any ideas??

thanks
~j

82vdub · Post by **82vdub** » Wed Mar 12, 2008 10:32 pm

I don't know what warm pressures should be, but I had over 90 psi at idle when it had cold oil in it years ago. What viscosity oil are you running?

Vincent Waldon · Post by **Vincent Waldon** » Wed Mar 12, 2008 10:48 pm

The one official spec VW gives is 2 bar (29 psi) at the filter flange, at 2000 RPM, with the engine at normal operating temperature (cooling fan has cycled once).

With the engine over 2000 RPM the oil light and buzzer will sound if the oil pressure at the flange drops below 1.8 bar.

With the engine under 2000 RPM the oil light will come on if the pressure at the head drops below 0.3 bar.

libbybapa · Post by **libbybapa** » Thu Mar 13, 2008 12:03 am

I don't think the '82s had the dynamic oil pressure circuit.

Your oil pressure is fine. 15 psi at hot idle is great assuming you're measuring from the end of the cylinder head. I'd have to look, but the low IIRC the pressure switch should trip the oil light at about 4 psi at the head. I'd assume a faulty sender.

Andrew

Vincent Waldon · Post by **Vincent Waldon** » Thu Mar 13, 2008 1:30 am

libbybapa wrote:I don't think the '82s had the dynamic oil pressure circuit.

Your oil pressure is fine. 15 psi at hot idle is great assuming you're measuring from the end of the cylinder head. I'd have to look, but the low IIRC the pressure switch should trip the oil light at about 4 psi at the head. I'd assume a faulty sender.

Andrew

Good point... it's an 81... missed that tiny detail !

82vdub · Post by **82vdub** » Thu Mar 13, 2008 8:46 am

libbybapa wrote:I don't think the '82s had the dynamic oil pressure circuit.

My 82 1.6NA Rabbit has the dynamic oil pressure circuit with the two oil pressure switches.

Vincent Waldon wrote:Good point... it's an 81... missed that tiny detai

Actually, the year isn't mentioned, but in JamesW's profile, it says 82.

On the oil pressure, you may have damaged intermediate shaft bearings causing low oil pressure when it warms up. You can try thicker oil, but it may not solve the issue and you may have to dig into this a little more to find out why the low oil pressure.

Krank · Post by **Krank** » Fri Mar 14, 2008 10:04 am

Mine's an '81. It's been a year and 15K since I rebuilt it. It's over #100 when cold, and it's about #25 when fully warmed up, measured at the end of the head (where the pressure switch is), using 15W-40. From what I've read, these readings are really about normal. If you take the reading from the top of the oil filter, it will jump up significantly (I think it was around #25 higher, but my memory's a bit fuzzy after this long of not looking at it there).
Hope that helps.

libbybapa · Post by **libbybapa** » Fri Mar 14, 2008 4:15 pm

As I mentioned previously, hot and measuring at the head, the sender won't trip until about 3-4 psi. I would be unconcerned unless it dipped below 10 psi at hot idle measuring at the head.

Andrew

rallydiesel · Post by **rallydiesel** » Wed Mar 19, 2008 4:15 pm

You're fine. Mine is 1 PSI at the filter flange when hot.

Yes I know, I need to fix it ASAP.

JamesW · Post by **JamesW** » Sun Mar 30, 2008 8:54 pm

Really 1 psi!!!! that sounds not good.

So I thought I had my self a little short term fix but I guess not after all.

I ordered a new pressure gauge for the flange, but ended up ordering the wrong one, 1.4 bar ~20 psi instead of the 1.8 ~26 psi one.

I measured pressure at the flange after the engine had warmed up, and left it idling for about 30 min, it got down to about 24 psi which I wasn't to worries about. And I installed the new, wrong pressure gauge. Seemed to work fine on test drive. I'm going to replace the oil pan gasket soon and take a look at the oil pump.

But today after driving for about 45 min, the light start flashing again at idle, just a touch on gas and it went off. Worst part is I'm not sure what my idle is set to b/w when I replaced my injectors i moved the idle screw to get access.

So Anyway I still have an issue, and I just read somewhere about a 30mm oil pump, can anyone tell me more about that as next up is pulling the oil pump to see how that looks (and clean the suction tube filter)

What size does my 82 have stock?

Thanks
James

dieselsnowmobile · Post by **dieselsnowmobile** » Tue Apr 01, 2008 8:16 pm

This is on my 1.6 NA diesel running 5w40 Rotella Synthetic with all readings are being measured at the head.

Idle cold = 100+ psi
Idle warm = 25+ psi
Idle very warm = 20 psi

70 mph warm (~3,000 RPM) = 75+ psi
70 mph very warm (~3,000 RPM) = 60 psi

Defintions:
warm - engine at operating temps (190F)
very warm - engine has been at operating temps for atleast 20-30 minutes

I use warm and very warm because it takes awhile for the oil pressure to settle on 60 psi while running down the interstate for atleast 20 to 30 minutes and then it will stay at 60 psi for hours running at about 3,000 rpms. Running around town, the idle psi will barely ever get below 40-50 psi. These readings are all summer readings as I just installed an oil pressure guage.

tawney · Post by **tawney** » Tue Apr 01, 2008 9:16 pm

I think the stock pump would be 26mm. The turbo models had the 30 mm size for the extra oil to the turbo and piston squirters.

Steve

libbybapa · Post by **libbybapa** » Tue Apr 01, 2008 9:33 pm

'87< had 36mm gear oil pumps.

Andrew

JamesW · Post by **JamesW** » Tue Apr 01, 2008 11:23 pm

Can I install a 36mm pump on my 82?

Would it help increase oil pressure or have any other useful benefits?

Thanks
James