My guess would be a burnt valve. Get a leak down test and verify.

 

Double check your test, 0 compression is a bit suspicious given it's running on 5. No compression would indicate complete failure of the headgasket, or cylinder rings. Both of which indicate via smoke in the exhaust. Does it billow blue or white smoke?

 

Or a hole in the piston

 

Maybe it's this?

https://www.youtube.com/watch?v=_Vo4fm0JDPY

 

Zero compression on most of these engine is either a bent or burnt valve, unusual on one of these engines, a broken valve spring could also be a contributor. If there is a problem with the head gasket or piston rings is usually there will be low compression, not no compression.

As mentioned run a cylinder leakage test, usually burned valves are the exhaust valve. But I would also check #5 compression again as well.

https://forum.e46fanatics.com/showthread.php?t=889143

https://forum.e46fanatics.com/showthread.php?t=904997

https://forum.e46fanatics.com/showthread.php?t=1124176

https://forum.e46fanatics.com/showthread.php?t=1244145

 

I also had a zero compression on my other car. Turns the valve snapped

 

Thanks for all the info fellas, I did another piston soak one last time with Marvel Mystery Oil over the weekend. Didn't help, still zero compression. I guess I'm going to have to take the head off and have a look. The burnt valve seems to be the most obvious culprit. I was suspicious of that because the car only has 137,000 miles on it. To bad I just can't drive it or pass inspection with just 5 cylinders because the car has plenty of power is very responsive and starts immediately when cranked.

 

See if you can find a borescope that will let you inspect the piston and valves from the spark plug hole.

 

From the 3rd link I provided above - https://forum.e46fanatics.com/showpost.php?p=17200056&postcount=25

Sometimes it helps if you review the information that has been provided.

 

From the 3rd link I provided above - https://forum.e46fanatics.com/showpost.php?p=17200056&postcount=25

Sometimes it helps if you review the information that has been provided.

This has got to be the gentlest way of saying "search n00b!!" that I have ever seen!
:lmao:

 

I do not post links because I have nothing better to do! I really try to be a value added contributor.

Horse -> Water -> Pump Tail

I mean there was an exact example of someone being able to visually see a burned valve with an inspection camera using the 90 degree mirror. While not easy, it has clearly been done. The problem is when the valve is bent and not burned this may be a very hard problem to see from within the cylinder.

Use/read the information that has been provided and search, but the problem is with searching many times the exact answer or prior post can be very hard to find.

 

I really do appreciate it jfoj, seriously though that was the only link I didn't click on.

 

Here's another symptom, when I first start it, it blows a big cloud of smoke then virtually stops smoking after that. This happens everytime I start it.

 

Seriously, a quick leakdown will tell you you have a problem with an exhaust valve, and then you'll pull the head.

If there was an intake valve damaged, it would melt the intake.

A hole in the piston would be poofing out oil like crazy.

But just running some compressed air into #5 when it's at TDC compression will confirm
(when you hear the air coming out the tailpipe)
that the exhaust valve(s) have a terminal problem.

I mean, really, you can use an air hose on a compressor, it doesn't
even take a real leakdown gauge. I made one out of an old sparkplug
I gutted, back in the 90's when I was a dumb young kid... with no money.

t

 

Pics

Thanks Toby, I don't have access to a compressor but I was able to get some pics of the piston. I could get the mirror to focus correctly to get pics of the valve.
I think I did find something interesting. Any input would be appreciated. This piston looks awfully clean for have over 130,000 miles on it.

 

That is indeed the money shot. That shiny thing is one of the compression rings.

<img src="https://farm8.staticflickr.com/7882/32927227808_27687187cc_z.jpg" width="640" height="480" alt="Untitled">

Here's what a healthy M54B25 piston looks like:

<img src="https://farm5.staticflickr.com/4836/46078050524_609a97c88f_z.jpg" width="480" height="640" alt="Untitled">

 

Looks clearly like the top edge of the piston is broken or melted. This is the top edge up the upper piston ring land/groove and you are seeing the top piston ring.

Not sure this is totally what is causing "Zero" compression. Usually to have "Zero" compression there is a valve related problem, bent, burned or broken. Hard for a ring land or even a single piston ring problem to cause "Zero" compression.

But at the end of the day, it looks like you have a lower end problem of some sort and may even have a cylinder problem as well.

I would be sourcing a used engine rather than screwing around with the current engine. Once you have the engine out of the car, you can pull the head and get a better idea of what really happened, but not sure I would bother trying to repair what you are looking at.

 

Thanks for the input guys, I'm really not set up to install a new engine. I guess I'll just try and sell it as is. Do you think I could get $1200 for it?

 

Thanks for the input guys, I'm really not set up to install a new engine. I guess I'll just try and sell it as is. Do you think I could get $1200 for it?

We don't know options colors or trim so would be hard to say how much you might get for it, however that much seems unlikely.

 

'04 325i w/137k miles and a bad engine? $500-$700

Manual might be worth more than an auto