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Author Topic: 19-20 PSI oil pressure on hot idle - too low?  (Read 932 times)

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Re: 19-20 PSI oil pressure on hot idle - too low?
« Reply #15 on: October 12, 2021, 09:12:57 am »
I think you have to remove the oil pump to access the oil jets.  You can give it a go but I doubt they are blocked. The bolts that attach them to the block are pressure relief valves and don't fire oil at the pistons until 3 bar.  An entire set of 4 with new bolts/valves is only £70ish, so not worth bothering with a clean up, just replace them if in doubt.

I wouldn't use 10W-40.  VW specify 0 or 5W.  You want the oil to be thin when cold.  10W is too stodgy over winter.  If anything, increase the hot end of the oil temp range and try a 5W-50.

Don't be too surprised to find the con rod journals and bearings are still in spec.  These engines aren't known for rod knock unless they've suffered complete oil pressure loss, and even then it's the cam journals that seize up first.


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Offline OllieVRS

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Re: 19-20 PSI oil pressure on hot idle - too low?
« Reply #16 on: October 12, 2021, 07:58:56 pm »
I'm not able to have a look at the engine until tomorrow, so meanwhile, I just wanted to go back to what you said earlier @Pudding about the oil pressure earlier

Quote
The oil pressure on these engines is well known to be weak at low rpm.  The only specification from VW is '39psi @ 2000rpm' which you've also found from some research.

Would you happen to know any specific numbers for the minimum oil pressure psi/bar?

This is what a poster on Audizine posted, for an Audi A4 B7 which came as standard with the 2.0 (T)FSI engine in the US. Since the Oil pressure switch opens/closes at 17.4 Psi, how come these are the right specs? Or is it dormant below 1500 rpm? The Audizine poster says it is "NOT monitored at idle".



Must I have been above 1500 rpm and also been below 17.4 psi simultaneously? Since the red oil lights, I never tested the car with the oil pressure switch in again.

Maybe in the meantime by replacing the PCV, Oil filter, and Pick-up pipe I've fixed the issue and I've not even realised? I only measured the oil pressure with a mechanical gauge after doing all of that work.

If the Audi forum poster is correct in what he's saying, could there be absolutely nothing wrong with my engine's oil pressure?  :stupid:

Edit: Audizine poster says switch activates at 1200rpm
« Last Edit: October 12, 2021, 08:23:28 pm by OllieVRS »

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Re: 19-20 PSI oil pressure on hot idle - too low?
« Reply #17 on: October 13, 2021, 01:26:43 pm »
This is the only information I can find.  It's a really crappy website full of adverts but the information is direct from VW, so will be correct.

It's a bit vague but from what I can gather, the oil light comes on below 1.2 bar and at 2000rpm (oil at 80 deg C), pressure should be between 2.7 and 4.5 bar.

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_(single_pin_oil_pressure_switch)/


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Re: 19-20 PSI oil pressure on hot idle - too low?
« Reply #18 on: October 13, 2021, 08:04:00 pm »
So I've just finished work on the car and am happy to report no up and down (vertical) play in the conrods. The crankshaft also looks clean (I only took off the piston 2 and 3 conrod caps).




Whereas the bearing looks a bit 'cloudy', I tried to use brake cleaner to clean them up, but I don't think it made a huge difference. I didn't want to risk scratching them so I didn't put much force in.




Luckily there's no pits in them from what I can see. Do I need to replace them?

Apologies for the photo quality, I must've had oil on the camera.
« Last Edit: October 13, 2021, 08:07:38 pm by OllieVRS »

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Re: 19-20 PSI oil pressure on hot idle - too low?
« Reply #19 on: October 14, 2021, 01:02:11 pm »
If the bearings and journals are smooth and your finger nail doesn't catch in any of the scratches, it's safe to sling them back in.

How ever, as you've gone that deep into it, it might be worth checking the clearances with a plastigauge kit and stick new bearing shells in if necessary.


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Re: 19-20 PSI oil pressure on hot idle - too low?
« Reply #20 on: October 14, 2021, 02:12:58 pm »
Thanks for the reply Pudding.

There is one bearing-long groove that does catch my nail on one of the two bearings.



On the advice of my mechanic friend I'm going to be replacing all of them, not just because of the groove or cloudiness but as a preventative measure too (and since I've already done all the work taking off the bottom of the engine).

Hopefully Skoda Ireland has them and if they do, for a reasonable price.

EDIT: Just called Skoda Ireland, they couldn't find anything for 'connecting rod bearings', but found 'Big end bearings' for €46 for 4 pairs, and it'd take a couple weeks for them to arrive. I told him I'd call back tomorrow when I'm sure they're the correct parts.

Are these  'Big end bearings' conrod bearings?


EDIT 2: I should've realised that the crankshaft bearings are the main bearings and conrod bearings are called big end bearings. I just missed my chance to order them today as the parts department just closed.

The sales person I spoke to when I called back the second time said he can arrange for the parts guy to call me first thing tomorrow at 08:30. I'll double check my car is definitely coming up as a 2.0 TFSi BWA in their system before I order though.
« Last Edit: October 14, 2021, 07:12:16 pm by OllieVRS »

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Re: 19-20 PSI oil pressure on hot idle - too low?
« Reply #21 on: October 14, 2021, 06:30:49 pm »
Just spotted a clue as to the car's history while looking at the oil pump to reference stretch bolts I needed for when I put it back.



I think one of the previous owners had the balance shaft sprocket bolt snap or come loose, as can been seen by the chip on the 'timing' hole on the top, also on the hole on the right and a slight chip below to the right of the right hole. This could also have been a source for the metal fillings in the sump I found when I dropped it for the first time.

Also, would anyone know if the bolt for the sprocket in question is a stretch bolt and what part number it is? It came off easier than a stretch bolt would, leading me to believe it isn't one or the previous person that put it in had reused it. Maybe I should reuse it but with some thread locker? I've attached a picture of the bolt I'm talking about (not my picture).



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Re: 19-20 PSI oil pressure on hot idle - too low?
« Reply #22 on: October 15, 2021, 07:51:21 am »
It is indeed a stretch bolt.  20nm + 90 degrees.  The 10 bolts that hold the pump to the block are also stretch bolts, 15nm + 90 degrees.

The upper left bolt hole looks suspiciously like a helicoil insert?

It does definitely look like someone has been in there before.

That bolt shearing off was actually a known issue on very early GTIs.  I don't know if VW ever addressed it but I do recall stories of VW having to replace the entire oil pump on several cars under warranty, and sometimes the whole engine.  It's a possibility that happened to yours. The bolt shearing off I mean.  In which case, reuse yours.

I can't find any info on the sprocket bolt, so you'll need to get one from the dealer unfortunately.  Any reference to that bolt online looks completely different, so I wouldn't trust the internet on that one.

Edit - had another look for the balance shaft sprocket bolt and can't find it.  The internet only lists the bolt for the oil pump sprocket.  Now that I remember, I did try and get that bolt last year when I suspected my balance shafts were rattling....and I'm pretty sure the parts guy said it only comes with the whole pump/balancer assembly, and not available on it's own.

« Last Edit: October 15, 2021, 10:52:07 am by Pudding »


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Re: 19-20 PSI oil pressure on hot idle - too low?
« Reply #23 on: October 15, 2021, 09:21:02 am »
Good spot on the helicoil Pudding.

Take the pic of the bolt to TPS, I've done a similar thing when I can't find a part number.

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Re: 19-20 PSI oil pressure on hot idle - too low?
« Reply #24 on: October 15, 2021, 11:27:53 am »
Called Skoda earlier this morning and have ordered 4 pairs of big end bearings for €46, and I confirmed with the guy my car was coming up as an FSI with a BWA engine on their system.

I also think I have found the bolt for the oil pump balance shaft. I used another forum's findings of the bolt being an M10x22mm (and from my findings uses a size 12 spline). It's a flywheel bolt and it comes up under two numbers: N90665001 and 034-H01-6009 , where the latter number seems to be specific to the 1.8t engine. I'm going to order two of the first number from the website in the last screenshot, so I have a spare in case I ever need to take the oil pump off again. EDIT: Have just measured my bolt, and it is indeed M10x22(.3)mm, and says 12.9 (grade) on the bottom.






As for the oil pump to block bolts I found a post here on Audizine (https://www.audizine.com/forum/showthread.php/680111-So-you-want-to-build-your-engine…-Well-here’s-how-to-do-it/page2) stating the different bolt numbers so I'm going to repost them here if anyone ever needs them. The Skoda dealer only had the bolts starting with WHT and were about 5 euro a piece, so I'm only ordered the first WHT bolt from them as it's near impossible to buy it online in the EU.

Quote
Set it down on the locating bushings & tap it down until it is seated. You want to use new bolts for this guy as they are stretch bolts & should not be reused, especially if you are retaining the balance shafts like I am. I have numbered the bolts to coincide with the ETKA part diagram that Charles.waite provided me in a different thread. (The silver bolt labeled as #16 is actually #17. The black #16 bolt is correct.)

Part numbers
#6 – WHT 000 360 A
#14 – N 911 495 01
#15 – WHT 000 006
#16 – N911 496 01
#17 – N104 305 02

Torque all of these bolts to 15 Nm or about 11 ft-lbs plus an additional 1/4 turn.


« Last Edit: October 16, 2021, 03:19:19 pm by OllieVRS »

Offline OllieVRS

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Re: 19-20 PSI oil pressure on hot idle - too low?
« Reply #25 on: October 16, 2021, 12:56:51 pm »
A neighbour has advised me that I should also change out the main bearings while I'm in there, as new connecting rod bearings will somehow negatively affect main bearings? Is this true?

Even if it is true, is it possible to change the main bearings on this engine without removing the crankshaft?

I'm not too concerned with oil pressure anymore ever since I read the Audizine post with the oil pressure specs. I'm only changing out the conrod bearings as a preventative at this point.

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Re: 19-20 PSI oil pressure on hot idle - too low?
« Reply #26 on: Today at 09:16:50 am »
Well done on finding the bolts mate, top man, very useful  :happy2:

No don't touch the main bearings.  You have to drop the crank to do those.  Main bearings never wear as they only deal with very light rotational loads, unlike the rod bearings which have to deal with very severe push-pull loads....especially the upper half.


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