Oil pressure question for V6 engine, MKB: AKN

Hello,

Unfortunately, I'm experiencing more problems with my V6 TDI than I had anticipated. Unfortunately, something has come up again, which means I also can't write anything meaningful for my other two posts that need to be completed .

Here's the problem. I suspect there's insufficient oil pressure in the right cylinder. Now, I have three questions about the oil circulation system. These questions came to mind after I read Erwin's workshop manual.

"As long as the oil pressure warning light doesn't illuminate when the engine is running, but does illuminate when the ignition is turned on and the engine is off, can I assume that the oil pump is still providing enough pressure? The oil pressure sensor reads 1.9 bar. It should be below 2000 rpm, and above 2000 rpm it should be at least 2 bar. Otherwise, the warning light illuminates. Since it's not illuminating, everything should be okay, right? This function is designed to immediately detect any malfunction of the sensor. However, I will still check the pressure. Hopefully, I can do it this week." I will report.

"Since I suspect the oil pressure is correct, but there might be insufficient contact on the right side, I'm trying to identify the cause. There's an oil return valve for each cylinder head (left and right). The manual states that if irregular hydraulic clacking is repeatedly heard, especially during short trips, and it disappears after a longer drive, this valve should be replaced. How does this valve work? I don't have one, and replacing it based on suspicion is quite a bit of work. Does this valve regulate the pressure? For example, does it open above a certain pressure (e.g., X bar) and close below that (e.g., low level or idle)? Is it just a throttle? What happens if wear from the camshafts clogs or blocks this valve?" Can low tire pressure occur under all driving conditions?

3) Are there other possible causes for low oil pressure in the transmission (TK) despite correct oil pressure in the supply line from the turbocharger? For example, could the oil filter housing be a factor?

Hoping for lots of tips and answers.

Thank you!
Tom.

Hi,

1.) If the oil pressure sensor is not queried in the following way: Once the engine speed exceeds a certain value (e.g., 2000 RPM), the oil pressure is checked. If the value exceeds a certain threshold, the warning light will turn on.

"The oil return valve prevents all the oil from flowing back into the oil pan. When restarting the engine, the oil doesn't have to be pumped from the oil pan to the furthest points --> the oil pressure builds up faster, and the lubrication points are supplied with oil more quickly. If there are deposits on the oil return valve (due to poor oil or oil that is too old), it may not close properly. When the engine is turned off, the oil then flows back into the oil pan, which means it takes longer for the oil pressure to build up everywhere when the engine is restarted." What kind of oil has been used so far?

3.) Oil filter housing: If the filter is clogged, there should ideally be a bypass, right?

Greetings from Tübingen, to Tübingen.
Sure, here is the translation of the text from German to English:

"Micha"

Mephisto wrote:

Hi, 1.) If the oil pressure sensor is not queried in the following way: Once the engine speed exceeds a certain value (e.g., 2000 RPM), the oil pressure is checked. If the value exceeds a certain threshold, the warning light will turn on. "The oil return valve prevents all the oil from flowing back into the oil pan. When restarting the engine, the oil doesn't have to be pumped from the oil pan to the furthest points --> the oil pressure builds up faster, and the lubrication points are supplied with oil more quickly. If there are deposits on the oil return valve (due to poor oil or oil that is too old), it may not close properly. When the engine is turned off, the oil then flows back into the oil pan, which means it takes longer for the oil pressure to build up everywhere when the engine is restarted." What kind of oil has been used so far? 3.) Oil filter housing: If the filter is clogged, there should ideally be a bypass, right? Greetings from Tübingen, to Tübingen. Micha

1) It needs to generate a signal below 2000 rpm; otherwise, an error will occur. According to the manual, it is also checked below 2000 rpm. Therefore, my assumption.
2) What does this valve do when the oil pressure is low? What happens if the valve gets stuck and remains open (not when the engine is off, which I understand, but while driving)? It's about short-distance travel, and the oil pressure builds up quickly.
3) Yes, I think so. But there's a flap for the KGE (presumably a specific component or system). I've found something about it in the search, but I don't understand it. Therefore, here's the specific problem I'm likely experiencing, and the question of what might be causing it.

So far, no LL (Longlife) oil has been used, but with a 50,000 km interval (large customer with a sticker on the service booklet) . However, I then used Castrol LLII 0W30 (506.00/01) and change the oil approximately every 30,000 km. It's included now.

Okay, please provide the German text you would like me to translate into English. I will only provide the translation.
We've met before, right? Don't you have a job in Tübingen?

If the valve is not functioning properly, there should be a noticeable oil leak visible around the cylinder head cover. They tend to do that anyway.

I have very little or no oil consumption. It does sweat a bit, but nothing serious and not from the ESD seals. If oil is leaking out, it would indicate that I have increased oil pressure. That is not the case.

If, according to your statement (sorry if I'm misinterpreting), the oil pressure increases with a blocked valve, then wouldn't the pressure decrease with a valve that's too open? Or am I completely wrong?

How does the oil cooler valve work, and what happens during driving if it remains fully open? Does this lower the oil pressure, or does it only have to do with oil returning when the engine is off? Why, according to the manual, do the valve lifters make noise during short-distance operation?

Herr Antje wrote:

1) It must provide a signal below 2000 rpm; otherwise, an error will occur. According to the manual, it is also checked below 2000 rpm. Therefore, my assumption.

I understand the principle with two oil pressure switches as follows:

When starting, the 0.3 bar switch must close.
Subsequently, the oil pressure should not drop below, for example, 2 bar, even when the engine speed is > 2,000/min (engine speed can sometimes be adjusted via OBD).

Okay, so far as I understand, there's only one switch that operates at 1.9 bar.

According to the manual, an error signal occurs when:
rpm <2000> 1.9.
rpm > 2000, pressure < 1.9.

The pressure switch is screwed into the tester and connected to an LED. The LED lights up at high pressure. As soon as it exceeds 1.9 bar, it shuts off.

Hi,

Short trips are bad, but not city driving! I mean: The engine runs for a few kilometers, then turns off for a few minutes. In these few minutes, the oil flows back into the oil pan due to a faulty valve.

Whether a faulty oil return valve results in increased oil pressure, decreased oil pressure, or no change in oil pressure depends on its specific location and the design of the rest of the engine.
If a faulty oil return valve is stuck in the open position, the oil pressure will not change. It simply takes longer for the oil to reach all parts of the engine and for the oil pressure to build up after the engine starts.

However, I don't understand why a faulty oil return valve could cause the lifters to rattle. The ball valve inside the lifter should actually be closed when the engine is off. Well, maybe one or two lifters will rattle when the camshaft is engaged and slowly empties the lifter... but all of them? How is that supposed to work?

Have you ever considered doing an oil flush on that engine? Maybe you'll be able to solve your problems without putting in too much effort.

Regards,
Sure, here is the translation of the text from German to English:

"Micha"

I understand the issue with short trips, but the oil pressure doesn't build up after a few hundred meters; it's actually only a few seconds after a cold start.

A flush with oil cleaner won't likely make much difference in new engines. Furthermore, fully synthetic oils probably help to prevent sludge formation. I don't really like using those cleaning solutions, but if nothing else works, I'll try them.

If the valve cannot be the cause of the low oil pressure, I will probably need to check the oil pressure very carefully. It's strange that it only affects the right-side connecting rod bearings, and the only thing in the oil circuit that's separated into a left and right side is the return valve.

Are there any other possible reasons why the oil pressure is okay at the turbocharger inlet, but the pressure is too low at the cylinder head (at the hydraulic lifters)?

Hi,

Don't hit me, I'm just having a hard time understanding: Why do you think the oil pressure is too low? Just because of the noise from the hydrants?


Regards,
Sure, here is the translation of the text from German to English:

"Micha"

You don't hit, otherwise, I feel like Frings .

According to the manual, 7 or 8 (out of 12) new, original VW hydraulic lifters were defective on the right cylinder head after 250-400 km, which I find impossible. The valves were checked for leaks. The valve timing was not misaligned, and installation errors have been ruled out. It sounded very bad.

Before the water pump was replaced, a significant amount of hydraulic knocking could be heard after the engine had been running for a while, but it would eventually disappear.

After installing new hydraulics, I've experienced a situation where the noise decreases or disappears after the system warms up. The noise remained the same, but a distinct clicking sound hasn't been audible yet (it's already making quite a racket). This usually happens after a few hundred kilometers, and I hope it doesn't get to that point this time. Exchanging these items is not fun (it takes 12 to 14 hours).

Is there a possible reason why the Hydros might be receiving insufficient oil pressure, even though there is sufficient pressure at the turbocharger's inlet? I've reviewed the information again. Possible causes could be: oil return valves (one for each cylinder head), a spring on the filter housing at the cylinder head, or the oil pump (although if that were the case, the turbocharger would also have experienced low oil pressure).

Thank you for your answers. I would appreciate multiple responses.

Tom.

Hello everyone,

I just wanted to correct something because I think I misunderstood something, or maybe Erwin (siehe Fehlerdatenbank) made incorrect statements in the book. I suspect that's the case.

Herr Antje wrote:

Hello, "As long as the oil pressure warning light doesn't illuminate when the engine is running, but does illuminate when the ignition is turned on and the engine is off, can I assume that the oil pump is still providing enough pressure? The oil pressure sensor reads 1.9 bar. It should be below 2000 rpm, and above 2000 rpm it should be at least 2 bar. Otherwise, the warning light illuminates. Since it's not illuminating, everything should be okay, right? This function is designed to immediately detect any malfunction of the sensor. However, I will still check the pressure. Hopefully, I can do it this week." I will report.

Okay, the oil pressure switch has a switching range of 0.7-1.2 bar, as far as I can still read (rather unclear due to contamination, not due to my condition ). However, the manual clearly states 1.9 bar. The values are likely being added .

"With the specified sensor, an oil pressure error is only displayed starting at 2000 rpm." The pressure is significantly above the shifting range at less than 2000 rpm, so this statement in the manual is likely incorrect.

That brings me to my values.
The oil pressure is approximately 3.5 bar, increasing to between 4.5 and 4.5 bar at engine speeds of 2000 to 4000 RPM. Therefore, there is no oil pressure error in the oil supply line to the turbocharger. The question regarding the regulated oil pressure per person, unfortunately, remains.

Okay, please provide the German text you would like me to translate into English. I will only provide the translation.
I (or rather, with the help of a friend) quickly built an oil pressure gauge because ATU didn't have a measuring device , and VW wanted to schedule an appointment, which I suspected would be expensive. The whole thing cost me about EUR 14.00. It includes a pressure gauge (scale 0-10 bar, 7 bar would have been sufficient), a hexagonal threaded fitting, a fuel hose with an inner diameter of approximately 5mm (up to 25 bar). It also includes a hose connection to the threaded fitting, 2 hose clamps. Then, a fitting was turned. One connection for the hose, one M10x1 (likely a relatively standard size for oil pressure switches), and a hexagonal fitting in the middle. Certainly.

EDIT
It's running again (for now?). Therefore, I won't do anything for the time being. The oil pressure seems to be okay so far. "Nevertheless, I would like to know exactly how the oil circulation system works, especially the mechanism located beneath the oil filter housing."

Thank you for your help!
Tom.