Volkswagen Passat Forum banner
1 - 20 of 25 Posts

·
Registered
Joined
·
295 Posts
Discussion Starter · #1 ·
my 04 gls is in serious trouble now. after losing power with a flashing MIL during a drive, i couldn't find the problem myself so i dropped it off at the shop today with the following codes:

- p0300, p0303, p0304

i've been thru this scenario before so i was expecting them to find a large vacuum leak, but they come back to me with no compression on cylinder 4 after a compression & leak down test.

the shop is recommending an engine replacement as a more economical option rather than tearing down the engine to search for the problem at the hourly shop rate.

well i paid for the compression test & told them i would have to consider my options vs the book value of the vehicle. i asked if the technician wrote down the values of the other cylinders and they did not which irritated since i just paid over $100 for the test. i can only assume (hope) if compression was low it would have been mentioned.

i'm searching the passatworld forums now for ideas on what to do, but figured i'd post this asking for everyone's help during primetime since i need to come to a decision soon.
 

·
Registered
Joined
·
7,822 Posts
Sure would have been nice to know the compression value on cylinder #3 at minimum.
I say that because you've got misfires on #3 and #4 cylinders. They might be related.

Are you able to do any investigative work on your own?
Squirt some oil down into cylinder #4 and retest for compression. If any compression comes back it would indicate an issue with the piston rings. If no improvement more serious issues are at hand.
Possible scenarios, blown head gasket between #3 and #4 cylinder, hole in top of #4 piston or an issue with valves.

A skeptical hunch at this time you're probably looking at pulling the engine.
Getting a used engine is a crap shoot. Some times you can score good, sometimes they are duds, like having poor oil pressure from worn out bearings and cause rod knock.

Me personally I would fix what you've got as you know what your history has been. But that's with an assumption you can do the work yourself.
It'll take just a little more sleuthing to get to a final answer though.
 
  • Like
Reactions: John_E

·
Registered
Joined
·
7,822 Posts
74k miles? I just caught that.
I would definitely fix what you've got. That's still a low mileage engine, there's some good long life left in it my opinion.

Too bad I wasn't still up in WI I'd offer to fix it for you. You're only about 70 - 80 miles from where I was living.
 
  • Like
Reactions: John_E

·
Registered
Joined
·
295 Posts
Discussion Starter · #4 ·
i'm thinking about bringing the car home. the offers i'm getting from the junkers are underwhelming. i thought with the crazy scarcity driving the prices of new & used vehicles they would be offering a little more than they usually do. of course keeping it means i'll probably have to sit on the car until it makes economic sense to fix (assuming prices ever go back to normal). maybe buy a car cover and let it sit next to the driveway.

i'm also interested in knowing the numbers...i can re-run the compression tests myself. i don't have the compressor & tools for leak down testing on the dead cylinder.
 

·
Registered
Joined
·
1,570 Posts
Unless you have oil burning issues (smoke in the exhaust), the more likely culprit for compression loss is in the top end, and if it came on fairly suddenly and affects 2 cylinders it’s probably a head gasket.
 

·
Registered
Joined
·
295 Posts
Discussion Starter · #6 ·
i got the car back. actually was able to drive it a little ways before having it towed. i ordered a cheap chinese compression gauge off amazon and got these numbers:

1 - 160
2 - 171
3 - 170
4 - 0

on a cursory look i'm not really seeing any oil in the coolant or coolant on the dipstick, but i could investigate more closely.

the original incident happened during normal acceleration probably around 30mph. there was no loud bang or pop, just sudden stumbling and shaking.
 

·
Registered
Joined
·
1,570 Posts
Given that the engine has low miles on it, and supported by the decent compression readings of the other cylinders, this is what I would do:

1. Verify cam timing, both at belt and chain. I don’t suspect this much, but it’s low cost to rule out whether the belt jumped a tooth or the chain tensioner failed.

2. Borescope look at cylinder 4. If it doesn’t specifically show the valve problem, it can at least confirm the condition of the piston and cylinder walls. If they are damaged, consider used-engine; if not, proceed to step 3.

3. Pull cylinder head. Refurbish head/valves and replace head gasket.
 

·
Registered
Joined
·
295 Posts
Discussion Starter · #8 ·
i ordered a $10 usb 5.5mm endoscope for my phone off amazon. it has a 90 degree mirror attachment so i should get video straight down and to the sides from the spark plug opening. maybe i can post somewhere if i get something decent off it.
 

·
Registered
Joined
·
295 Posts
Discussion Starter · #11 ·
all the sparkplugs had more or less the same wear and appearance when i changed them somewhat after the fact. they all kinda looked like the engine was running rich which is hardly surprising given all the misfires. i could take pictures of the old plugs if you think it's worth pursuing.
 

·
Registered
Joined
·
7,822 Posts
Right off the cuff I'm going to guess it's something to do with a valve issue. Like a sucked valve or one that's stuck open slightly.
If you can get in there see the valves with a bore scope, all 3 intake valves should be in the same position as each other, whatever position that is relative to where the engine is on it's rotation (technically the center intake valve opens just slightly before the other two) but for this exercise they should be same, as should the 2 exhaust valves be in the same position to each other.
At this point I think at minimum, pulling the head will be required whether it's a valve problem or piston / cylinder wall problem.

Maybe, you'll get super lucky and all it will be is a messed up cam follower (hydraulic thingy between cam and valve). That can be done with just the removal of the camshaft.
Just trying to put a positive spin this, yeah?

On a side note:
Those compression numbers are indicative of a very healthy engine. If this were me, I'd make the fix. Way cheaper than buying another car.
But then again, if you need an excuse to get that 'other' car...
 
  • Like
Reactions: Urlik

·
Registered
Joined
·
100 Posts
my 04 gls is in serious trouble now. after losing power with a flashing MIL during a drive, i couldn't find the problem myself so i dropped it off at the shop today with the following codes:

- p0300, p0303, p0304

i've been thru this scenario before so i was expecting them to find a large vacuum leak, but they come back to me with no compression on cylinder 4 after a compression & leak down test.

the shop is recommending an engine replacement as a more economical option rather than tearing down the engine to search for the problem at the hourly shop rate.

well i paid for the compression test & told them i would have to consider my options vs the book value of the vehicle. i asked if the technician wrote down the values of the other cylinders and they did not which irritated since i just paid over $100 for the test. i can only assume (hope) if compression was low it would have been mentioned.

i'm searching the passatworld forums now for ideas on what to do, but figured i'd post this asking for everyone's help during primetime since i need to come to a decision soon.
I vote a problem with the valves. I have seen a 1.8t with a chipped valve and of course the compression was very low.
You can use an endoscope and see if the piston is intact and that should indicate the problem is in the cylinder head.
IMHO The leak down test should have indicated where the problem exists IF that test was ever done or done correctly.
You do not want a JY engine! You probably will be making more problems with that option.
Pull your cylinder head, have it reconditioned and reinstall it. It is a pretty easy job to do. I think I can remove and install the cylinder head in a few hours and I have done several cylinder head replacements on the Passats/Audis with the 1.8t.
Paying a shop for a head replacement (labor $800) including normal head reconditioning (around $600) and parts ($200 new bolts, gaskets, oil, filter, coolant), should cost you around $1600. Labor costs vary and possibly so does machine shop work.
Whereabouts are you?
 

·
Registered
Joined
·
295 Posts
Discussion Starter · #14 · (Edited)
i got the endoscope down into cylinder 4, but the mirror on the 90 degree attachment was messed up so all i could get was video straight down. the piston appeared to be pretty high up in the cylinder so i really only got a good look at the top of the piston and one of the valves. i have no idea if anything looked out of place...i suppose i should have looked down some of the other cylinders while i was at it. i'm returning the camera to amazon for a replacement and when i get the 90 degree attachment working i will move the crankshaft and try to get a better look from the bottom of the cylinder looking up. in any case, here is a link to the footage i recorded:

google drive mp4

someone asked about the spark plugs so i took a couple snapshots since they were still laying out:
Circuit component Material property Household hardware Gas Electric blue

Household hardware Gas Auto part Engineering Metal


also, i'm located in hanover park, il to the person who asked.
 

·
Registered
Joined
·
1,570 Posts
What you can tell from the video is that the piston crown looks fine, and one valve is sticking down. Towards the end, there is kind of a half-moon dark spot around 5 o’clock that may just be carbon but possibly a “valve kiss” spot?

While waiting on the camera, I would pull the valve cover and see if any valve looks stuck open, and check out the CCT too.
 

·
Registered
Joined
·
10,390 Posts
It appears that there are metal fragments embedded in the top of the piston.
I suggest you take the head off, and inspect thoroughly.
If there are metal particles embedded in the piston, the piston would need to be replaced.
 

·
Registered
Joined
·
7,822 Posts
Spark plugs look fine as far as they are still all intact.
I'm a bit concerned about all those little marks in the top of the piston. Something was flying around in the cylinder at some point in time recently.
I have no idea what it was (broken lip of a valve, meh) but something was definitely in there, maybe got blown out through the exhaust, maybe that valve is hung open with something wedged in there.
My opinion, that cylinder head is gonna have to come off.
 
  • Like
Reactions: Tomvw

·
Registered
Joined
·
478 Posts
Wow, I agree with Tomvw that there are metal fragments embedded in the top of the piston and on the intake side of the valve. Scratching my head wondering where the heck those metal fragments came from and piecing the puzzle together about no compression in that cylinder.

Here is my hypothesis:

Metal fragments came from the turbo vanes rubbing on the turbo body. Sucked into the engine, enough to hang a valve in cylinder #4 so it got bent = no compression.

Those spark plugs are "al carbon" from oil burning, could also be from the failing turbo pumping oil into the intake.

Would like to see what the other pistons look like and how much play there is in the turbo shaft.
 

·
Registered
Joined
·
10,390 Posts
4zfed's hypothesis seems feasible.
If this hypothesis is correct, all 4 pistons and the head would likely need to be replaced.
Turbo would need to be cleaned and repaired, or replaced. The intake path from turbo to valves would need to be thoroughly cleaned.

AndreasPassat suggested "(broken lip of a valve, meh)", this is also feasible.
In this case damage should be confined to only cylinder 4

The head definitely needs to come off.
 
1 - 20 of 25 Posts
Top