A week after buying the car, I noticed that while standing at a parking spot or a traffic light (i.e. at idle), the dash would show “Switch Off Engine! Oil pressure too low” along with the oil can icon. It only appeared with warmed-up oil, in the 75-85°C range. If the oil was colder or hotter than that, or the car wasn’t idling, you wouldn’t see the message.
If I gave it some gas or just started driving, the error message disappeared. Apart from this error, I didn’t notice any other changes in how the car behaved. I hooked up a diagnostic cable and read the codes with VCDS. Found an error in the engine control unit:
15189 — Pressure sensor; used when oil pressure decreases P164D 00 [039] — malfunction Not confirmed — Tested after clearing the memory
I started digging through forums; the causes of this error ranged from a faulty low pressure sensor to clogged oil channels. It’s practically impossible to diagnose the exact cause more precisely.
Since I had a service due, I figured I’d change the oil and the low oil pressure sensor and get away with it. Bought a Delphi SW90017 sensor (aftermarket) and Motul 5W-30 oil. Yeah, no such luck. The service was done, and the error started showing up again a couple weeks later.
I went to see a mechanic I know who specializes in engines. He said that with over 100k km, I could try a slightly thicker 5W-40 oil, since I’d just had a service done and put in 5W-30. I rush out, buy new oil, and go to the shop to have it changed — done. On the first day after the change I tried to reproduce the error and couldn’t. But the next day I had to wait a couple minutes for someone in a parking lot, and while standing there the error popped up again. Well, I thought, here we go — I talked it over on the specialized forums and with shop mechanics, and pretty much everyone said you can’t drive with this error, that there’s oil starvation happening and it can lead to serious consequences, up to the engine seizing. I left the car parked at home and started digging through forums and talking to people who’d had the same error.
In the club chat, amaryllis (Mary Inred) responded to the error and said she’d had a similar error that went away after work on the brake master cylinder (GTC). But she also said that acquaintances of hers had the same error, and it was fixed for them by replacing the oil filter housing and the pipe inside it with the newer revision. Masha helped me find the latest part revisions by VIN — VAG 06L115401J and VAG 06L115678Q. I buy the parts, go to the shop, and the mechanic says let’s measure the pressure with a gauge first so we know exactly what’s causing it — we’ll measure before and after replacing the filter housing.
We measured it, and indeed the pressure was low (~0.8 bar) both before and after the replacement. The normal pressure ranges are:
Idle speed = 1.2-2.1 bar 2000 rpm = 1.6-2.1 bar 3700 rpm = 3.0-4.0 bar
I got frustrated again and kept looking for a solution.
In the comments on one of my earlier journal entries, Hirayuki wrote in — turned out he was from my city and had the exact same error, and he’d gone through parts one by one (cheapest to most expensive), starting with the sensor and oil just like me and ending with the camshaft bearing bridge. Turned out I’d basically followed his whole path already, and the camshaft bearing bridge was all that was left.
I also rewatched a bunch of engine teardown videos by suslikrus. I also consulted with Alexey on where to look for the problem, and he also said to pull the bearing bridge and check the camshaft journals.
While researching the camshaft bearing bridge topic, it turned out this is a weak point on Gen 3 engines. On older bearing bridge revisions, the oil feed channel to the camshaft journal is smaller, so less oil gets delivered, and over time scoring can appear on the camshafts while the hole in the bridge widens, which lowers the oil pressure in the system. The old revision bridge is part number 06L103144F, and the new revision is 06L103144H. But the genuine part was out of my budget at the moment, so like Hirayuki, I bought an aftermarket one — 50007670 KOLBENSCHMIDT, which seems decent and is also built to match the latest genuine revision.
Went back to the shop and handed it over to the mechanic for the job. I wasn’t there during the actual replacement. Toward evening the mechanic sent photos and said the car was ready.
After the replacement, idle pressure went up to 1.3-1.5 bar, which is within the normal range. Hooray!
I also asked the mechanic to take a look at the camshaft journals. He said the wear depth was ~0.02 mm and not critical.
In the end, the error and the low pressure were beaten. Thanks to everyone I pestered with questions while sorting this whole mess out 🙂
Cost of the job: 3,200 UAH. Mileage: 128,800 km