[SOLVED] 19-20 PSI oil pressure on hot idle - too low?

[OllieVRS]

I'd like to start this off by saying I probably bought a 'lemon'. It's not a mk5 GTI, but rather a 2006 MK2 Octavia vRS 2.0 TFSI with the same BWA engine as the GTI. I thought this would be the best place to post this as this forum has the most knowledge about this engine. Any help is greatly appreciated 

Here's the backstory:
The day after I bought the car (unfortunately from a private seller) I got a flashing low oil pressure light when I was driving back slowly through my housing estate. There was a slight burning smell that scared me, show I turned off straight away. This was after a spirited drive on the main road, going up to 5k revs twice. It disappeared as quickly as it popped up. I checked oil level (was fine) and turned it back on. Drove it back home through the estate with no light.

The next day I got a friend with VCDS on his laptop to come over and check it and he said it's best to try and recreate the issue while driving, since it was intermittent. We went on a drive, and I tried to drive exactly the same way as I did the previous day. It somehow didn't come back.

Went on two drives, one 10km and the other 40km without giving it any serious revs and it didn't pop up.

Then while picking up a friend from work, I was showing off and accelerating harshly through each gear, it was fine was fine until I started slowing down to a light, going down to about 1k revs at 30kmh when the light popped up again. It was late in the evening so I pulled over in the bus lane and turned off the engine. Turned it back on, drove up to the red light, it popped up again as I was slowing down. I made it in to the estate just off the junction and as I stopped in the estate it popped up again. You can probably imagine how embarrassing whole ordeal was

I called the same friend that has the VCDS and he arrived 10 minutes later. He started the car and revved it, but the light didn't come back. He took off the oil cap with the engine running and nothing changed. He told me to limp it the local garage under 1.5k revs but to stop if the light came back. It didn't.

Mechanic checked it out but said he only had time to check the oil and he said that he thinks someone had added and oil additive to raise the oil pressure to mask some kind of issue. He advised me to contact the local engine rebuilder . I phoned the rebuilder and he said he was too busy to take on anymore work, so I decided to try my best to fix it myself.

After getting it towed home, I changed the oil and filter and did a simple compression test. All cylinders were in the 140-145 psi range. VW says it should be 170psi+ for new engine and it's time for a rebuild under 109 psi so I think I'm ok that front.

After doing some research, I replaced all the different components, such as the pick up pipe inc. o-ring, oil pump chain cover (which some of the plastic had broken off of), cam follower inc. stretch bolts and o-ring and finally the PCV and its rubber seal. While I had the sump off I checked the pump chain for tension and it seemed fine. I tried wiggling the balance shaft of the pump but there was no play whatsoever.

After the nightmarish task of getting the oil pressure switch connector off and switch out, I installed the US.PRO oil pressure tester kit. I then filled it up with some Castrol Edge 5W-30 LL. Also to add the sensor wasn't filled with oil on the connector side, so I don't think it's the problem.

Testing:
The oil pressure gauge is a bit strange. The pressure only goes up, never down by itself. To get and accurate reading you have to press the relief valve at the bottom of the gauge, which squirts out a little oil but 'updates' the oil pressure reading. I am not sure if this the intended behaviour, as it didn't come with any instructions nor could I find any on the web.

60psi on cold idle. This gradually goes down to 20psi as the engine warms up.

When revving while hot, it increases to 60psi, or 80psi if revved even higher than that.

But measuring it after revving it, it drops to 19psi.


The verdict:
I don't know where to go next - I know it's a bit low, but I can't find any reliable info online for minimum oil pressure. It passes the "39-65psi @ 80 degrees @ 2000RPM" guideline, which is the only official guideline I could find.

The oil pressure gauge may not be deadly accurate since you have to release some oil pressure to get an updated reading.

Should I maybe put in a different viscosity oil to raise the pressure a bit? I know inevitably it will need a rebuild, but I just couldn't afford to that at the minute. Trying to get a replacement engine from a scrapyard in Ireland is tough, as only one scrapyard across the country has the engine, and they weren't willing to give me a quote over email. When I looked the scrapyard up, it just looks like a metal shed at the back of someone's house . I doubt they'd give a warranty on it.

The oil pressure gauge is still connected to the car. I haven't taken it out yet as Pelican Parts advises to replace the oil pressure switch every time you remove it due to the washer needing to be replaced each time on the switch.

Any suggestions are greatly appreciated 

[GVK]

Balance shaft fix needed, see AKS tuning.

[pudding]

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.

Most tuners in Europe ditch the whole pump/balancer assembly and fit the pump from a 1.8T, but that goes hand-in-hand with a balancer shaft delete, which is essential on highly tuned engines with extended rev limits.  They spin at twice crank speed and don't like being over revved.

The only other reason the balancers seize up is due to neglect.  There are 1000s of very high mileage GTIs/Skodas/Audis etc out there still on the original pump.  It's a massively exaggerated problem, mostly by tuners trying to sell you a delete kit.

Anyway, going off a tangent there a bit  What state was the sump in when you did the pickup pipe?  All dark brown and varnishy?  If so, it's probably not received the best care and attention over the years. Perhaps an oil squirter or 2 has partially blocked reducing the pressure a bit.

Did the PCV fix the oil cap issue?  If the PCV is good, the engine should try and stall when removing that (or the dipstick) when it's running.

[OllieVRS]

Apologies for the late response, I was positive I posted a reply before but it seems to have disappeared.

I have since put 5W-40 in and it has improved the hot idle oil pressure by about 1-1.5 psi. The 5W-30 I drained out didn't have any sludge or metal particles, albeit I only ran it for an hour or so with it. 

I wanted to get a 'realistic scenario' road test so I got my friend to sit in the passenger seat and stick his arm out the window to hold the gauge. After driving to warm the car up for 20 minutes or so, I did some hard pulls to try and get the oil as hot as it realistically could be. We did 15 minutes or so of harsh acceleration to roughly 5-6k revs each time, and measured the oil pressure at a dead stop at idle. On a side note, throughout the entire testing the engine sounded completely fine, no weird knocks or noises.

In latter half of the 15 minutes the lowest the hot idle got to was 17.5-18 psi, which is just in spec according to a reply in https://www.vwvortex.com/threads/oil-pump-balance-shaft-delete-info-to-decide-if-how-you-should-do-it.9418861/#post-114539301. The poster says

"17-30psi at for idle oil pressure at normal operating temp and 39-65psi for 2K RPM rev at normal operating temp."

Not once during the testing the oil pressure suddenly drop below 17.5, a symptom of the balance shaft seizing afaik. I am keeping in mind this test was in 12 degree weather, so I don't know how much lower the pressure would be if it was warmer outside.

I consider this outcome good enough to put her back on the road. I should be getting a new sensor by Friday so I can report back then if anymore lights pop up.

What state was the sump in when you did the pickup pipe?  All dark brown and varnishy?

There was a little bit of 'dirt' on the edges of the sieve in the pipe, but nothing significant enough to have blocked oil flow. Yes, the sump was quite dark brown and varnishy, which is a probably as a result of the previous owner not having done a service for the last 15k miles, which I somehow missed while looking at the car. Yes, I know I'm an idiot.

Did the PCV fix the oil cap issue?

Yes, the engine revs drop quite a bit now with the oil cap removed.

[bobby_fodge]

I had a similar issue when the oil was hot the pressure would drop and cause the dash light to come on.

Tried loads of different things but the only that solved it was a balance shaft delete kit from AKS.

https://www.akstuning.co.uk/shop/home/550-tfsi-oil-pump-balance-shaft-delete-modification.html

[OllieVRS]

While the switch hasn't arrived yet, I've had a brain wave - the minimum hot idle oil pressure for this engine is 17.4psi, as that's when the Oil Pressure switch toggles. Meaning if I put the sensor back in right now, it would probably definitely come on at idle once the engine is properly warmed up. 

@bobby_fodge you said the balance shaft delete fixed the issue for you, but did you measure the oil pressure difference in psi/bar before and after the delete? I'd do a balance shaft delete but as I live in Ireland (within the EU), sending my current oil pump to the UK is simply out of the question. There's also the option of a €175 Freewheel from VIS motorsport.

I'd prefer to replace the pump if I had to rather than deleting/disabling the balance shaft though, as I read online it makes the engine very loud, and generally the engine constantly vibrating isn't good for it's lifespan.

If I remove the oil pump, how do I check the condition of the balance shaft? Would replacing the pump actually increase the oil pressure? I read online that the oil pressure isn't made by the pump, but by the bearing tolerances etc. Apologies if that's a stupid question, I'm just getting really desperate to fix the issue without replacing the whole engine.

EDIT: I've just realised from looking at a picture of my oil pressure gauge that I've been misreading it. Between 0-20 psi there are 2 separating thin red bars, whereas between 20-40 psi and above there are 3 separating bars. Meaning instead of me calculating 17.5 psi, it was actually 16.6 psi on hot idle, definitely below minimum. Now it makes sense that the previous owner added an oil additive to mask the issue. I'm going to drop the pump as soon as I have time and investigate, hopefully I find a problem with the pump otherwise it's time for a replacement engine 

[pudding]

Yeah it is the bearing clearances, turbo oil feed, cam bearings, cam phaser supply holes etc that creates the oil pressure.  The pump just provides the flow. That said, if the pump is restricted by a clogged pick up pipe, it can have the same effect.

[bobby_fodge]

The only pressure testing was when the car was stationary which was pointless as the oil pressure light on came on when driving, the engine was fully up to temp and the revs were very low. Changing gear to keep the revs from dropping too low meant the oil pressure light didn't come on. But that was obviously not a long term solution.

I replaced the oil pressure sensor, pick up pipe, cleaned the sump oil and changed oil and filter a couple of times even though I always change oil/filter well before the VW interval. None of these work made a difference. I was thinking I'd need an engine rebuild.

I'm on another car forum and an engine builder said it'd be the oil bleeding past the balance shafts.

The engine doesn't seem any louder with the delete kit fitted and the oil capacity is now a little larger also. AKS can sell you the deleted unit and then you send them your old one back. That would keep you on the road.

[OllieVRS]

Well, I was really hoping I'd find a problem with the oil pump, but when I took off it was perfect, both shafts rotated very smoothly.

But what was unfortunate was what I found above the oil pump (

). 

In addition to that, here is what the underside of each piston looked like:

Piston 1:


Piston 2:


Piston 3:


Piston 4:


Piston 2 looks very burnt, as also evident from rocker cover on camshaft where the cam shaft looks burnt above piston 2.


Since the oil pump seemed perfect, is it time to start looking for a new (used) engine? Or is there any chance this one can still be saved? The blue scorch marks and wiggle in the rod ends make me think it's pretty terminal.

[LC5F]

Looks fine - the discoloured area on the cam is the oil fill location.

You may be better off going direct to VIS for your free wheel -but the modification that AKS do is remove as much of the balance shaft as possible and plug up certain oil ways and they use the VIS freewheel too

[OllieVRS]

@LC5F @bobby_fodge Just uploaded a video of my oil pump, correct me if I'm wrong, but it seems fine? There's no resistance or wiggle in the balance shaft. Also just to note, the first time I took off the sump there was a bolt in it, that had fallen out of the oil pump, meaning someone has already removed the pump before.

Also, I've showed the video to a friend who's been working as a mechanic for a couple years tell me that he thinks the rod end bearings are gone and "definitely looks like the engine was running in a lean condition causing scoring and that discolouration". Since it passed the compression test at 140 psi a cylinder and the oil pump seems fine (from what I can tell) it has to be the rod bearings or oil squirters, no?

I've had afterthought from reading a post on another forum saying that 17.4psi isn't the minimum oil pressure, as the switch isn't read by the ECU under 1500rpm, could this be true? I was getting 16.6psi at hot idle on 5W-40. 

[bobby_fodge]

As I was out of ideas I bought the AKS part without checking my current balance shafts. I was at the point of looking for engine rebuild prices so was desperate and willing to just try it.

What about trying this, just the sprocket and much cheaper than the full AKS delete kit?

https://www.vismotorsport.com/copy-of-ea113-oil-pump-balance-shaf

[pudding]

I'm not seeing a whole lot wrong there.  Con rods are supposed to have horizontal play (but not vertical play!) and the clean areas on the pistons just look like where the oil squirter were doing their job?

The dark staining is typical of engines on long life servicing, but not necessarily a sign of terminal damage.
 
Was the 140psi compression reading on a hot or cold engine, and was the throttle wide open?  The spec for a new engine is around 14 bar (200psi), so yours is way down if the test was done hot at WOT.  140 isn't too bad though.  You only notice reduced compression at idle and part throttle.

I don't think you're at the new engine stage just yet. 

[OllieVRS]

The 140psi compression was at cold.

I talked to my local mechanic who said I should take the conrod caps off and have a look at the rod bearings for any pitting/wear signs on them, as well as pitting/wear on the crankshaft. If there's only wear on the bearings and not the crankshaft, then it can be saved. Wear on the crankshaft would probably warrant a rebuild/engine replacement.
He also mentioned if I put it back together I should use 10-40W Instead of 5W-40.

I'm 99% sure the pump is fine, and there's no vertical movement in the conrods, could it be the oil squirter?

I've just realised as I was writing that last sentence that you can see one of the squirters in the picture of piston 2.


Are you able to take the squirters out without removing the crankshaft (a.k.a tearing apart the engine)?

I really wouldn't have the tools or environment necessary to take the engine apart much more than I have already. And getting an engine rebuilt professionally costs nearly double that of getting a replacement used one.

According to a user on another forum, taking out his oil squirters and cleaning them raised his idle oil pressure from 0.4 bar to 1.2 bar, so this is something I'd be interested in looking into, before emptying my entire wallet for a replacement engine. _{Also wanted to give a quick thanks for sticking with me so far guys}

[LC5F]

All looks OK to me too -
You would have to drop bearing caps to see if there is any wear in there.
If the squirters were blocked they would increase oil pressure.

Watch this YT vid it shows the issue of balance shafts not being snug enough in the housing, the oil feeding the shaft can easily flow out - not holding oil pressure: