Expansion tank level looking unchanged, and a moderate 'pschutt' of pressure release when opened this morning.

Chain elongation fault code had returned since last cleared.

1 Fault Found:

18723 - Chain Elongation

P150D 00 [01101101] - -

Confirmed - Tested Since Memory Clear

Freeze Frame:

Fault Priority: 2

Fault Frequency: 1

Mileage: 266043 km

Date: 2029.14.24

Time: 12:08:37

Engine speed: 2531.00 /min

Normed load value: 28.6 %

Vehicle speed: 103 km/h

Coolant temperature: 92 C

Intake air temperature: 20 C

Ambient air pressure: 1010 mbar

Voltage terminal 30: 13.913 V

Unlearning counter according OBD: 40

Timing deviation after chain replacement: intake bank 1: 1.56

Timing deviation after other repairs: intake bank 1: 0.00

Timing deviation: current value intake bank 1: 5.93

Chain elongation: no. of valid initial values: intake bank 1: 5

Readiness: 0000 0100

Think I might acquire a spare engine and work on it to be ready for a quickish transplant if required. If only I had plenty of space. ☹️

I have acquired the chain repair kit 03F198158B at what seems like a bargain price of <£120 from a local dealership.

Includes chain, cam and crank sprockets, guide rails, tensioner and all screws and bolts; but now unsure if it would be a poor investment of time and effort to use this on the current engine.

Anyone know what, if anything is different in the complete CBZB engine for an automatic versus a manual transmission car? My favourite, low-mileage complete one currently on ebay is from an auto.

Edit: researching the above question, flywheel is different, but tends to be un-included in spare engines I've seen. Then some bits of the breather system seem different, but not a lot else.

Edited 10 January10 Jan by Breezy_Pete

Been watching lots of chain-change videos on YouTube, and had an idea during one this evening.

Bodgery warning, look away if you are inflexible of thought or attitude, please.

Background is the chain elongation fault mentioned above, and a 165k mile engine that actually runs pretty nicely and quietly after the first few seconds from cold start.

Chain tensioner was replaced at least 6 months back, with new genuine.

Reluctant to invest a full chain kit and all of the associated labour, effort and time, on what might not have a lot of life for other reasons.

Both crank and cam sprockets are floating, unkeyed fits on their respective shafts. Crank one is a tight interference fit that goes nowhere easily.

Cam sprocket may be accessed relatively easily by removing the top, plastic, section of cover (which has a slight leak anyway).

Rotationally, it's fixed only by the friction associated with tension of the screw.

I own the locking tools for crankshaft and camshaft.

What if...

... I set the engine to TDC (or as near as poss. with the elongation that supposedly exists) with the two locking tools.

Loosen off the tensioner to give a bit more slack in the chain.

Counterhold and loosen the cam sprocket and replace screw loosely (with new one). Avoid dropping chain down the hole.

Re-tighten the tensioner; ensure both locking tools now set crank/cam correlation correctly.

Torque and angle tighten new cam sprocket screw.

Remove locking tools, turn engine through 1 turn of cam sprocket, test that both locking tools now indicate ideal timing.

Refit top plastic cover carefully and cure slight oil leak.

Does that make any sense, to anyone? 😁

Seems like a plan that might have a fair degree of risk, but potentially sort out the elongation effect on timing, temporarily at least, with very little time, effort or parts.

Mad? Cunning?

Edited 11 January11 Jan by Breezy_Pete
Various corrections and changed ideas

Worth stuffing a non-fluff rag down below your workings to act as a dropped item catcher.

2 minutes ago, MikeTheThinker said:

Worth stuffing a non-fluff rag down below your workings to act as a dropped item catcher.

Yes, good shout. Also to catch old sealant cleaned off after removal of top cover. 👍

And some string tied through the rag in case that falls in? 😆

There is some logic there... I just can't work out in my head if it will work... I guess what you're doing is adjusting the cam sprocket to accommodate the amount of chain lengthening between the crank and cam which has put the timing out. With the tensioner taking up the slack on the other side it sounds plausible but I'd query why that isn't a typical 'fix' as opposed to a new chain... which makes me wonder if it wouldnt work.

Need to think on it...

Edited 11 January11 Jan by skomaz

I don't know how often @Tech1e checks in these days but I suspect his knowledge would be worth listening to.

@skomaz , yes, good summary of what I hope will occur if it goes well.

Risks include the tensioner running out of adjustment length, I guess. I will be asking more from it if I try this.

It would indeed be interesting to hear Tech1e's thoughts on this, thanks Lee. Think he might be a bit too well trained and bodge-averse to like the idea though. 🙂

You never know, Pete. He might have even thought about something similar himself 🤷

Eventually found the locking tools that I knew I had bought, after a battle with my oh-so-tidy (not!) garage. Also a spare cam sprocket screw, so I can keep the chain kit complete.

Realised that a first step logically involves attempting to correlate the error code with a measured incorrect cam angle, by just using the crank and cam locking tools, no disassembly other than removing the bits to fit those.

With crank lock tool fitted and crank held turned tight up against it, I should be able to see how much of an angle the cam locking tool isn't aligned by.

Only thing I wonder is whether it's best done with engine cold or at working temperature; probably the latter, I guess, but I may try both.

Anyone know what the two pins are for, on the right in the box?

Edited 26 January26 Jan by Breezy_Pete

Are they not locking pins, Pete?

5 minutes ago, Lee01 said:

Are they not locking pins, Pete?

Possibly. What would they lock though?

51 minutes ago, Breezy_Pete said:

Possibly. What would they lock though?

Not entirely sure. I had a thought that that's what they are but I was watching Flipping Bangers earlier and as luck would have it, they were doing a cam belt on a Citroën XM (a cheap future classic IMO) and Gus used a pin to lock a lower pulley (crank pulley I believe it was) directly into the engine block. Makes sense to lock the crank and the cam.

It was on U and Yesterday channel at 20:00 GMT

Edited 27 January27 Jan by Lee01

I'll see if they get mentioned in the workshop manual.

Cheers.

Thanks Lee, I soon discovered that they are in fact pins to help locate the upper (plastic) timing cover whilst refitting with sealant gasket on two surfaces:

I guess they guide the cover into just the right spot at the first attempt, preventing squidging of sealant into places it shouldn't be. Insert all the other screws, then remove these pins to fit last two screws.

I've used similar, but homemade things when refitting sumps with liquid gaskets.

Will be helpful now that I know what they are. 🙂

Edited 28 January28 Jan by Breezy_Pete

On 26/01/2026 at 15:08, Breezy_Pete said:

Realised that a first step logically involves attempting to correlate the error code with a measured incorrect cam angle, by just using the crank and cam locking tools, no disassembly other than removing the bits to fit those.

With crank lock tool fitted and crank held turned tight up against it, I should be able to see how much of an angle the cam locking tool isn't aligned by.

Got round to this today, only a couple of months later. 😁

Tried but failed to get a decent photo of the misalignment of the cam locking tool when crank was pushed hard up against crank locking pin.

But it was definitely off, no way the screw was going in. My best guess is that it was about a third of the (M6) screw diameter out, in the retarded cam direction as expected. I think that calculates out at about 4.5° which isn't far from what VCDS is saying. Engine was warm, but not at operating temp.

So I think Easter weekend will see me attempt the re-alignment of the cam sprocket as mentioned a few posts above, amongst other jobs.

Front right corner is making a squelchy noise recently, which I think may be the shock breathing its last few gasps. I have everything needed to swap that whole strut out, on a much lower mileage wheel bearing housing, so I may aim to get that done too.

Howdy @Breezy_Pete

I just stumbled on this topic.
The CBZA engine is a very basic and easy to understand and maintain however, as you have noticed, there are many small things that, if not payed attention to, will become an issue over time.
I stripped everything down around the block to fix all air and oil leaks, gaskets and everything else that suffers after 250.000 mls/40x.xxxkm's.

See my struggles linked below:
CBZA refurb
If you have any specific question, please reach out. I am pretty sure i have seen it all before.

Link to every known POF of the CBZA:
CBZA Points of Failure
(Activate subtitles)

Edited 29 March29 Mar by stigma
Added link to POF video

Wow, a quick visit to that photo collection says to me that you have done a lot to your engine!

My biggest concern at the moment is a very slow coolant loss that seems to be accompanied by pressurisatuon of the cooling system that is present even when stone cold.

That suggests a serious problem to me, which may mean that a replacement "younger mileage" engine may be a better plan than lots of work on this one.

(Almost 270k km done).

I have been servicing this car since my better half has owned it at 110.00km.
From turbo/wastegate refurb to interieur rewiring to ...i don't even know anymore

If you are indeed losing coolant at steady pace, this could stem from a number of issues:

-Leaking waterpump/thermostat(housing) (almost always)

-Leaking inlet manifold (highly likely)

-Cracked block (not a know issue)

There is ofcourse a myriad of hoses that also microcrack under operating temperatures.

Best way to test this is to pressurise the cooling system and let it sit for at least an hour.
If it drops, you have an active leak.

2 minutes ago, stigma said:

Leaking inlet manifold

I like that idea, because it might also explain the lasting pressurisation (addition of gases whilst running).

I also have a spare intercooler matrix I could try.

I have been speedreading thru your topic however, i am trying to understand what the underlying issue is.

When you opened up the rad cap with a stone cold engine, you hear pressure rise/vent, or see bubbles rise (air being sucked inwards).
Did it happen once, or does it always happen? Does it happen even if the system has not been pressured from driving after the first attempt?

Edited 29 March29 Mar by stigma

I believe it is pressure venting. It seems to vary, sometimes when I check there is very little release, but this evening it seemed quite a lot (but not much coolant loss).

It is probably 4 weeks since I last checked, so only a very slight problem currently.

Thanks for your interest.

I guess just disconnecting both hoses from the intercooler and joining them would make an interesting test.

Even though i follow your logic, this would be a ineffective way of investigating whether you have a leak or not.
Pressurizing the system will get you a yes/no answer allot faster without any mess.

Cooling system pressure tester

Apologies if my forwardness in answering feels harsh. I am a pragmatist at heart.
I cannot look into your wallet nor do i know your facilities or capabilities however, i think having this set will expedite this investigation allot.

Looking forward to your results.

9 hours ago, stigma said:

Best way to test this is to pressurise the cooling system and let it sit for at least an hour.
If it drops, you have an active leak.

Thing is, the car is doing this all on its own.

The perceived pressure in the expansion tank had been there at least approx 48 hours since the car was last used.

I think bypassing (or just substituting) the intercooler should give a definitive answer one way or the other for that as a cause of the pressure.

Coolant leaks without pressurisation don't worry me, they are usually easy to fix.