Request: Oil pressure info from Bentley Manual

[OllieVRS]

Hi guys,

Could someone with a Bentley Manual please take a picture/scan of the oil pressure related page(s) from the Bentley Manual?

This is just out of curiosity, my oil pressure is fine but I'd like to see what they say about it and it's not an easy book to get my hands on, living in Ireland.

Many thanks :)

[pudding]

Information about oil pressure specifics is very hard to pin down, largely down to VW's vagueness.

Assume you've seen this? https://workshop-manuals.com/volkswagen/golf-mk5/power_unit/4-cylinder_injection_engine_(2.0_l_engine_turbocharger)/engine_lubrication/parts_of_lubrication_system/checking_oil_pressure_and_oil_pressure_switch_(2-pin_oil_pressure_switch)/

I don't think the Bentley will tell you any more than that, but what I'm gathering from the VW manual is the normal pressure at 80 degrees (after the fans have kicked in at least once), at idle, should be 1.2-1.6 bar.

If you are checking the pressure at, say, 100 degrees, the number will be lower due to oil viscosity thinning out, but the low pressure sensor would appear to trigger if the pressure falls below 1.2 bar.

[OllieVRS]

Information about oil pressure specifics is very hard to pin down, largely down to VW's vagueness.

Assume you've seen this? https://workshop-manuals.com/volkswagen/golf-mk5/power_unit/4-cylinder_injection_engine_(2.0_l_engine_turbocharger)/engine_lubrication/parts_of_lubrication_system/checking_oil_pressure_and_oil_pressure_switch_(2-pin_oil_pressure_switch)/

I don't think the Bentley will tell you any more than that, but what I'm gathering from the VW manual is the normal pressure at 80 degrees (after the fans have kicked in at least once), at idle, should be 1.2-1.6 bar.

If you are checking the pressure at, say, 100 degrees, the number will be lower due to oil viscosity thinning out, but the low pressure sensor would appear to trigger if the pressure falls below 1.2 bar.

Thanks for the reply Pudding. The problem is that the oil pressure switch isn't read below 1250/2000RPM. The reason I've put two RPM figures is because people on different forums report two different read points. Before I got remapped it read at 1250, after getting remapped it reads from 2000. I know this because I've done multiple oil pressure tests with the sensor disconnected, and those are the RPMs the light will trigger at.

So what VW are getting at is that the switch should physically open at 1.2-1.6 bar, unrelated to the RPM, to test the switch is working correctly. But they fail to mention the switch isn't polled below the aforementioned RPMs.

The problem is VW only state a single benchmark for the oil pressure, the one at 2000RPM @ 80deg oil. Our engines can suffer from insufficient oil pressure outside that benchmark, e.g. at idle due to oil spray jets or a stuck PRV, or at 3000 RPM or above due to a weak PRV spring. Their benchmark only covers low oil pressure when its low across the board, such as from a worn balance shaft or blocked pickup etc.

I already once found oil pressure specifications on the Audizine forum, presumably taken from the Bentley Manual. Hence why I wanted to confirm that the specs I found were accurate, as that's what I've based nearly two years of oil pressure measuring on.

Here's what they were:

Idle 1-1.2 bar or (14.5-17.4 PSI )
2000 RPM 2.7-4.5 bar (39-65 PSI)
3000 RPM 3.5-4.5 Bar (51-65 PSI)

The oil pressure switch is not polled by the ECU at idle.

[OllieVRS]

Bonus post, actually found the forum post I originally got the information from. Here's a screenshot of that:

[pudding]

Yeah exactly, as I say, vague 

All VW are essentially saying is, so long as the switch remains closed at 1.2 bar, all is good. No mention of rpm below 2000rpm.

Therefore one can assume the engine is happy if doesn't throw the oil light on the dash, because they are assuming if the pressure is good at 2000rpm, it's good everywhere else. Very strange.

Old VWs used to have oil pressure gauges, but since the 2000s, they stopped fitting them as to not alarm people about the low pressures at idle when hot!

From the data you've gathered so far, it would seem yours is where it needs to be. 

Mobil do a 5W50 for older engines, which I would favour over a 10W60, which I know some folk have run in the past.  That would certainly help prop up the low rpm pressure a bit.  It's a band aid I know, but not sure what else you can do short of fitting a brand new pump @ £1500+VAT!

[pudding]

Have you considered the 1.8T pump conversion?  It's well known in highly experienced and skilled TFSI circles that the stock setup is borderline at best.

God knows how mine lasted 180K miles on the original pump before I sold it!

[OllieVRS]

Have you considered the 1.8T pump conversion?  It's well known in highly experienced and skilled TFSI circles that the stock setup is borderline at best.

God knows how mine lasted 180K miles on the original pump before I sold it!

I haven't considered it no, as I always considered my pump to be functioning correctly and not the cause of the low oil pressure on my engine. Now that my pressure's back in spec, I'm happy to continue with my pump.

I have previously mentioned the PRV may be dodgy, but I'll be keeping an eye on it with oil pressure checks every service. I've removed the oil switch so many times that I can probably get an oil pressure gauge tool up and running in 45 minutes. 

Also just a question, is the 1.8t an engine-out kind of job? Because how else would you get its chain onto the crankshaft sprocket? Or does the chain have one of those links you can disconnect?