VP37 leaking in the high-pressure part.

Hello everyone,

I have already read several of the relevant articles on this topic.

Regarding the vehicle: Audi A4 Avant, manufactured in 1999, with AFN engine.

Vehicle is driving normally, don't think there's anything wrong.

The car has approximately 225,000 km on the odometer.

After noticing the stains on my car, I finally decided to investigate where they were coming from.

I was also able to find the solution relatively quickly: It is most likely the O-ring on the distributor body. The high-pressure and low-pressure sides of the fuel pump are located here.

I remember reading somewhere that you can also replace this one when it's already installed.

Here, the high-pressure part was loosened to the point where the O-ring became visible, and then it was replaced.

Does it even work to get the O-ring over the high-pressure part?

Wanted to minimize the effort required for this exchange.

Or do you think the better approach would be to completely remove the ESP and completely dismantle the high-pressure component, as described in the technical article?

I once put a mirror under the ESP to see what was happening, and I saw diesel dripping onto the mirror. Of course, the engine was running.

See image.

While I can't pinpoint the exact location of the leak, the O-ring seems to be a very likely culprit.

See image.

This is the pump:

First, determine the true origin of the diesel.

There are several candidates for the VP37, such as the spray control valve, metering pump, etc.

On the other hand, replacing the HD part, the rubber ring, seems quite simple.
Remove the shut-off valves from the HD part. HD-part slowly and in sections, loosen screw by screw until something comes out.
It's best to get 2-3 O-rings, as they can sometimes break.

Warm up the O-ring slightly and knead it with your hands. Then, wipe it off and hope that it doesn't tear.
Compared to expanding, removing the timing belt, disassembling, reassembling, adjusting, etc., it is definitely a worthwhile alternative.
Alternatively, I remove the HD part while it's still installed.

But it's only for puzzle solvers with nerves of steel.

The suggestion about the soup of the day is good.

Okay, bitte gib mir den deutschen Text, den du übersetzt haben möchtest.
Unfortunately, I am unable to access external websites, including the one you provided. Therefore, I cannot translate the text from the given URL.

Best regards, Rainer.

Thank you for the tips.

So, I took on the bigger job and removed the pump.

I have now also reassembled everything.

I'm facing the problem that I need to bleed the system.

I once had an Audi 80 with a 1Z engine. That's how I always did it, through the tank.

So, I pressurized the tank with compressed air and then diesel started coming out at the front, near the ESP. Unfortunately, this doesn't work with the A4 size; there's nothing at the front.

In the description I have, it states that a vacuum pump is attached at the top of the ESP, where the lines come from the fuel injectors and the fuel flows back into the tank, and then suction is applied.

Unfortunately, I don't have that. How did you do it back then?

Fill ESP via the fuel return, loosen fuel injector connection nuts during starting attempt until fuel starts to flow. Then try to start "properly".

Loose cover nut = Starter burns out.

Best regards, Rainer

I managed to get the engine running yesterday.
The problem was that the injection timing was not correct, according to the TDI Timing Tool.
Wanted to then gently turn the pump.

But unfortunately, a serious mistake occurred.

I forgot to engage the locking pin in the ESP and was about to start.

I think the timing belt has jumped over the crankshaft and a piston has hit the valves.

Okay, I've taken the straps off and everything back to OT, or rather, I've adjusted them to the markings I made for myself.

Well, the engine is back on, and it was running, but you can already hear something wrong in the intake tract.

Do you know what the associated costs are for replacing the valves?

Could I just beat myself up all day?

Greetings

Thomas

Ouch!
I know why I stand by my methods.

First, relax your mind. Maybe only 1-2 valves are bent.
You can probably replace the valve yourself.

Check all valves that the pistons have made contact with!
Even a small gap is enough to allow the valve to eventually burn out.

Well, I won't do that, I'm more familiar with automotive repair.

Hopefully, he'll arrive on time.

I have been feeling a lot of respect for technology again since yesterday.

I also think that only 1-2 valves are bent, otherwise the engine won't run.

Hello,

I decided yesterday to finally take a break.
First, I measured the compression. On 1-3-4, almost 35 bar in cylinder 2, there was nothing.

After I had removed the cylinder head cover, I discovered a crack on the 1st cam of the camshaft, and I could see the corresponding part, the cylinder head gasket, with the imprint of the cam. Well, I think the valve was fully open and the piston was pushed against it.
The crankshaft also has a missed shot. I think you can bury the head.

Valve of cylinder 2 is bent. One could see that.

What is the most advisable option here? On the internet, both used and overhauled heads are offered. For used heads, the mileage is important.

Regarding the renovated ones, I'm not sure what to make of them.

If you go to a parts supplier, you'll pay significantly more, and what you get is also a bit of a gamble.

Does Stahlgruber and Co. also sell complete heads?

Or is it more advisable to sell the car parts like this?

I recently had a wild animal damage incident, and my A4 was declared a total loss due to this.

Good advice comes at a price.

Here's also a picture of the hook.

Hi,
Which cylinder does the damaged camshaft belong to?
After all cylinders except number two are in good condition, I would
- With the old crankshaft when the valve stems are removed, inspect the NW bearings for any abnormalities (only check two bearings at a time).
If the head is not warped and the bearings are not showing any problems, it is possible to rebuild the head:
- Replace damaged valves with new ones; re-grind new valves;
- new pistons, depending on mileage, every (> 200 Tkm);
- New camshaft.
The individual prices (around 500.-) should be compared with the price for a swap ZK.
ZK Seal, ZK Screws, and Timing Belts are definitely included.
What do the pistons look like?
hg
Herbert

So, the cam belongs to the first cylinder.

It had a pressure of 35 bar. It also ignited where I was measuring.

I was already thinking that the camshaft would also need to be replaced.

I've only been browsing on eBay so far, it's Sunday after all.

On cylinder 2, you can see an imprint.

Otherwise, I haven't noticed anything.

Cylinder 1 surprisingly had no imprint.

Hi,
The damage could have a different cause. In my opinion, if there was a hard impact, the valve and the piston would have been damaged first. The compression values are good.
Please provide an image of cylinder #2 here.
hg
Herbert

Image of Cylinder 1, which is currently on OT.

I didn't quite manage to get a picture of the 2-cylinder engine. The battery on my phone was already dead and the piston was at the bottom.

Just checked with the scrap metal dealers.

One had an AFN engine without ESP and turbo, with a mileage of 247,000 km from an A4 for 300 euros.

He also has one with 204,000 km for 400 euros with a turbo.

The number on the cylinder head matches the one from my A4.