Felicia 1.3 Cylinder Head Corrosion Around Coolant Ways

[KenONeill]

As I said earlier, a permanent error code is easier to deal with. The code says the oxygen sensor is open circuit. The most probable place for the wiring  to break is shown below. But check the entire cable and connector. If the cable is OK... you need a new sensor. In that case, lots of WD40 and a special socket will make the removal easier.

 

Or you could use a proper dismantling lubricant like PlusGas rather than Water Dispersant 40.

[RicardoM]

Or you could use a proper dismantling lubricant like PlusGas rather than Water Dispersant 40.

Actually WD40 stands for Water Displacement, 40th formula.

 

And here is how to make yourself better, cheaper penetrant oil.

 

Edited 1 January, 2016 by RicardoM

[KenONeill]

Actually WD40 stands for Water Displacement, 40th formula.

 

And here is how to make yourself better, cheaper penetrant oil.

 

I stand corrected, but you're the only person to have noticed that in literally years. I recommend PlusGas because it's released fasteners in minutes where WD40 has left them effectively locked after 90 minutes or more.

[RicardoM]

No problem, I make errors too from time to time. Hopefully I will be corrected to become more knowledgeable by learning from mistakes.

[Breezy_Pete]

If coolant was ending up going through the exhaust, either by direct route into combustion chambers, or indirectly via oil mist with a coolant content, it could well have caused the oxygen/lambda sensor death. I can't remember exactly what it is in coolant that damages them, but I'm pretty sure it's bad for them.

[areed]

Thanks all for the replies again.  I gently tightened the sensor fitting this morning, which hopefully will stop the leak.  I also ran the car up to temperature while monitoring the lambda voltage:

 

 

According to the manual, the voltage should be between 0 and 1V when the car is warm.  My voltage started around 1.35V, and didn't drop when the car warmed up.  Apologies for the poor picture quality, I'm running VCDS Lite under Wine and for some reason it would stop measuring when I tried to take a screenshot. 

 

I had another close look at the wiring, and couldn't see any obvious damage:

 

 

Thoughts?

[RicardoM]

For now things look bad re. oxygen sensor. But for extra precaution, repeat the live data session and try two more things:

• wiggle the wiring of the sensor when engine is warm to see if the voltage starts fluctuating in 0.1 - 0.9 V range
• initiate a data logging procedure (see PM) by clicking on Start button in bottom part of window.

Start data logging before starting the engine. Stop data logging when the engine is warmed up. A log file will be created in subfolder Logs. Start Vag-Scope from VAG-COM and load recorded file to see a graphic representation of data. Archive the log file and upload it somewhere for us.

Edited 1 January, 2016 by RicardoM

[RicardoM]

One more thing. How is the engine starting and running now?

[areed]

Thanks again for the replies, I will log data and try wiggling the leads tomorrow morning.

 

One more thing. How is the engine starting and running now?

 

The engine starts first time normally (with the exceptions mentioned previously).  It sounds to me like it doesn't run especially smoothly to begin with - the idle speed is somewhat irregular.  This settles down once the engine has been running for a few minutes.

 

At low engine speeds there is a bit of a rattle from the engine too.  My guess is that this is from the timing chain.  

Edited 1 January, 2016 by areed

[RicardoM]

You can record a video so that we see and hear the engine. Your comments on video are welcome. If you get close with the camera to suspect noisy areas, the noise will be picked up better. I use to put one side of a long metallic rod on different parts of the engine and the other side I touch on the housing of the camera. It is like recording using a stethoscope.

[areed]

Ok, I ran the engine up to temperature while logging the sensor output, the log file can be found here.  The engine start looks like this: 
 

 
And stopping:

 
Wiggling the sensor cables with the engine warmed up had no visible effect on the voltage reading.  I also recorded a video of the engine starting and warming up:
 

 

I had to reduce the quality a fair bit so that the file could be uploaded on our slow internet connection, if a higher quality is needed I can reupload it in a couple of days.

Edited 2 January, 2016 by areed

[RicardoM]

The good news is you did a great job on both VAG-COM data logging and video recording of engine warm up. Other members should learn from you that a video helps us diagnose strange noises or malfunctions.

 

The bad news is you need an oxygen sensor. Data logging shows it is completely dead. The engine runs in "open loop" mode (a program stored in the memory of ECU) instead of using a continuous feedback from the oxygen sensor and adapting accordingly.

 

The noise on video looks like is coming from the bearings of the alternator. To be 100% sure, use a long screwdriver, put the handle to your ear and the tip on the housing of the alternator. Do the same on the water pump housing and also on the cover of the timing chain. Try not to touch any moving parts. Avoid wearing any scarf, necklace, etc. that might interfere with the engine.

[areed]

Thanks for the reply!  I have ordered a replacement sensor, which I should get within a day or two.  I will have a go at sounding out the rattle either tonight or tomorrow.  

 

An unrelated problem turned up late last night as I was unloading the car, too.  The outside door handle on the passenger side rear door no longer opens the door (the inside handle works fine though). The handle hasn't jammed, it just doesn't seem to release the door catch for some reason.  I had a quick look and couldn't see anything obvious, though it was dark. Have you seen this kind of thing before?

[RicardoM]

I have ordered a replacement sensor, which I should get within a day or two. 

Is it Bosch? Or an 'universal' type sensor?

The outside door handle on the passenger side rear door no longer opens the door (the inside handle works fine though). The handle hasn't jammed, it just doesn't seem to release the door catch for some reason.  I had a quick look and couldn't see anything obvious, though it was dark. Have you seen this kind of thing before?

The little rod I painted in red popped out or broke.

[areed]

Is it Bosch? Or an 'universal' type sensor?

 

I don't know, sorry.  I rang the local motor factors, who have supplied me with all the parts I've needed so far.  They have ordered one in from their supplier based on my engine code.  Presumably this will be more specific to my engine than a universal sensor.  What should I look for when I go in to see it? Is Bosch the make of the original?

 

The little rod I painted in red popped out or broke.

 

Thanks, I'm guessing I need to dismantle the inside of the door to access this?

Edited 4 January, 2016 by areed

[RicardoM]

Is Bosch the make of the original?

Yes. Bosch 0258003745-760 LSH 25. VAG code is 6U0906265C.

Thanks, I'm guessing I need to dismantle the inside of the door to access this?

Yes. The door panel must be removed.

[areed]

I have collected the new sensor, it is a Cambiare VE381085 which seems to be specifically for the Felicia.  The workshop manual says the threads should be greased with "G5" prior to fitting, what is G5/what should I use?

[Breezy_Pete]

New lambda sensors usually come with some thread lube on them, and a plastic cover over that, have you had a close look at it?  If it is dry, I have some VW "hot bolt paste" I could send you a dollop of, not sure what the part number is, but it's exactly for this sort of application. 

It may be worth getting a garage to loosen the old sensor for you, as they can be very awkward to remove, even with appropriate tools, once they've been in place for a number of years.

 

Example of pre-greased threads:

Edited 6 January, 2016 by Wino

[RicardoM]

Any anti-seize will do.

Smear a light coat of anti seize grease to the new O₂ sensor threads only.
 DO NOT get any anti seize grease on the sensor head as this can damage the sensor.
 DO NOT use any silicon based compounds; they will poison new sensors inoperative.

 

As Wino said, depending on how (un)lucky you are, sensor removal might need 'gentle' persuasion with a blowtorch. A suitable wrench socket helps (see photo) or you can simply cut the wires of the old sensor and use a regular deep socket. When you install the new sensor, don't go crazy on it with the wrench. Snug is enough.

 

[areed]

Thanks for the replies guys!

 

New lambda sensors usually come with some thread lube on them, and a plastic cover over that, have you had a close look at it? 

 

On closer inspection, it looks like there is some grey grease of some kind on the threads.  I tried to take a picture, but its not very clear unfortunately:

Presumably this means I don't need to apply extra anti-seize grease of my own.  I have some copperease which I could use if not.

 

I'll give the sensor a good soaking in plusgas before I try to remove it, this worked for the manifold bolts so hopefully I will be lucky here too.  I bought the special socket when I collected the sensor, so I won't need to cut the leads.  

 

When you install the new sensor, don't go crazy on it with the wrench. Snug is enough.

 

How crazy is crazy?  The workshop manual says tighten to 50Nm which is pretty tight, so do you think I should do less than this?

[RicardoM]

Take as a reference the radiator fan thermo-switch that you've snugged. Same torque. By "crazy" I meant lug nuts crazy.

[areed]

Had a go at removing the sensor tonight, and as you guys predicted unfortunately it seems to be stuck fast. :(  I refrained from trying with a big breaker bar as I thought this would probably do more harm than good to the exhaust system.  The downpipe is quite badly rusted where it meets the catalytic converter:

 

 

 

 

This has me considering buying a replacement downpipe.  I am very nervous to try and use a blowtorch under the car to loosen the sensor, and looking at the state of the downpipe if I removed it from the car I fear the flange that fits to the cat might just disintegrate.  Any advice?

 

I also spotted this bodge when I was under the car tonight:

 

If I'm not mistaken this is the linkage from the gear lever to the gearbox, so why does it look like its held together by a tiewrap? Should I be worried about this?

Edited 7 January, 2016 by areed

[Breezy_Pete]

Downpipe looks fine to me. That end of the exhaust tends to be much less prone to rusting through, because it's never really wet inside, unlike sections further back where it's cooler.

Have you applied generous amounts of penetrating fluid to the sensor? I favour PlusGas.

I would try smoothly applying a long breaker bar, but if that fails, and before you round off the hex of sensor, drop into your friendly neighbourhood garage and get them to loosen it for you. They'll have the best tools, and know how to safely apply heat without collateral damage.

Edited 7 January, 2016 by Wino

[RicardoM]

Oh yeah... the dreaded exhaust flange... I've seen worse and still holding. But if you buy a new downpipe, you'll have 4 advantages: no need to mess with the old sensor or pay a garage, easy to install the new sensor, peace of mind you have a solid front exhaust, and the satisfaction of another DIY job. One disadvantage: thinner pockets. If you decide to buy it (we call it 'the saxophone') buy also the gasket-ring thingy (see photo new vs old)

 

The botch job I see looks like a safety wire to hold the screw in place. Not sure though because of mud. Try cleaning the mechanism and assess the play.

 

Edited 7 January, 2016 by RicardoM

[areed]

Thanks for the replies guys!  I've generously applied plusgas (the wetness in the pictures), and will have another go at removing the sensor tomorrow evening.  If I can't get it off, I think I will replace the downpipe rather than try pot-luck with the garages here (I don't know any of them as I've only been in the area a few months).  The exhaust system after the cat looks fairly new, so it is only this bit that is really rusty.  Plus, having had the manifold off recently, I know that one end of the downpipe will be easy to remove at least.

 

The botch job I see looks like a safety wire to hold the screw in place. Not sure though because of mud. Try cleaning the mechanism and assess the play.

 

I will give this a clean when I have another go tomorrow, to see what the state of affairs is.