The car ran at temperature for 1h or so, drove it around and the coolant stayed the same. 

 

I don't know the answer, not sure what chuffing sound you are hearing, I may have got used to it or something.

I give up, engine bottom ends don't just fail unless you've run it out of oil.

 

I suggest you drive it in the meantime until a more definitive problem appears.

6 hours ago, Bertie90 said:

The car ran at temperature for 1h or so, drove it around and the coolant stayed the same. 

 

I don't know the answer, not sure what chuffing sound you are hearing, I may have got used to it or something.

 

Any external signs on the engine of where the coolant has gone? What did the coolant look like before the steel seal? 

 

Run the car with the header tank cap off, turn the engine off and see if it bubbles.

 

Does it drive and idle smoothly despite the noise? 

 

Not the best idea pulling injectors on and off on a modern diesel, but if pulling the injectors one at a time didn't effect the noise you were looking for, I'd be more tempted to look at something that's attached to the engine as the source. Have a good listen around the engine, see where it's loudest from. A mobile phone video won't really help because you don't get directionality. 

 

I think realistically you're looking at two separate faults that between them look really bad.

 

I wouldn't worry too much about the fact you've steel sealed it. It does work as a temporary head gasket fix. If there's signs of bits of it floating around, and you're fairly certain the engines not terminal, it might be worth doing a coolant flush. 

Edited 11 September, 20223 yr by StevesTruck

On 01/09/2022 at 20:04, sepulchrave said:

 

Unfortunately those chemical testers are not always reliable, particularly on diesels, a big end is a much louder metallic knock, a little end is a metallic click and a broken piston ring ticks.

 

They're far more likely to give a false positive due than a false negative. 

I’d suggest it’s worth paying a Garage to get them to diagnose. Otherwise you’ll just end up swapping a huge number of parts which will cost far more than a £60 diagnostic fee.

this is why the coolan has gone.

 the tank is split in the middle.

 

I seriously doubt it, imagine the pressure needed for the tank to split along the moulding line, the tank cap would release the pressure long before that happened.

 

If you release the pressure in the system by loosening the cap the coolant level should creep back up again.

i watched it coming out with my own eyes 👀

 

Ok, so how did that happen, the pressure in the tank must be crazy, are all the coolant pipes rock hard? Have you tried releasing the pressure when it cools down?

Thats a bit oddball. Are you sure it's not the cap seal or the level sender sending a tiny amount of water down the outside of the tank, which is then accumulating on the lip? 

Edited 11 September, 20223 yr by StevesTruck

Not at all, it comes bubbling out from the middle of the tank. Pressure must have been high yet no pipes are leaking and I have had the cap off. But should there be pressure like that in the system?? I bought another head gasket tester and I have negative results again. I waited until everything was up to temperature and did it mani times. I went and placed it near the exhaust after just to humour me and it turned yellow within less than a minute.

 

I'm actually waiting for a friend to spare a weekend and help me pull the engine out. Might take it down to a garage first and ask for their diagnostic.

 

Yep, that is a bit random. I wonder if the header tanks been replaced with a poor pattern one at some point. Either way, I think I'd chance a new tank and cap before taking the engine out. 

 

Like I say, I think you're chasing two separate faults that together look bad.

Edited 12 September, 20223 yr by StevesTruck

everyone, I present you the reliable 1.6 TDI engine with 126 000 miles. Go figure. 

 

 

the cranckshaft bolt head has somewhat snapped off and I have unscrewed the bolt by hand. 

 

 

What does this mean? Do I need to check for scooring? can I just add a new bolt?

Edited 25 September, 20223 yr by Bertie90

Congratulations, you have a unique failure.

 

Since that's a main bearing cap you need to remove the other bolt and the cap so you can inspect the crank journal itself.

Difficult to show, the journal has these stripes that run horizontal from one end to another. I think I might be ok. 

1 minute ago, Bertie90 said:

Difficult to show, the journal has these stripes that run horizontal from one end to another. I think I might be ok. 

Why not replace all bearings and bolts while you have the sump off and oil drained it makes sense as it would do another 100,000 miles no problems 

I will 👍

3 hours ago, Bertie90 said:

Difficult to show, the journal has these stripes that run horizontal from one end to another. I think I might be ok. 

 

That's the bearing shell, the journal is on the crank which looks ok and if it passes the fingernail test, is ok.

 

The shell looks ok as well but bear in mind that you cannot safely replace the upper half of the mains with the crank fitted as trying to slide them round will end up doing more harm than good. I appreciate the temptation but bearing shells really don't wear unless they get oil starved, some of the sputter coating has gone from that shell but it's far from dead.

 

In your place I'd simply replace both bolts on that main bearing cap and button it back up.

 

3 hours ago, thomasaspin said:

Why not replace all bearings and bolts while you have the sump off and oil drained it makes sense as it would do another 100,000 miles no problems 

 

Sorry but I don't agree for the reasons set out above.

Edited 26 September, 20223 yr by sepulchrave

I am with you 100% on that.

 

I have successfully changed lower and upper main bearing shells in situ but would not even think about putting a different shell onto that crank, that one has barely run in.

 

I am surprised at the lack of radius between the bolt head and shank and very shocked that VAG would use a setscrew (threaded along the whole shank length) OK it does not have the same loading as a big end cap bolt but its very bad practice.

 

Can anyone confirm that the offending item is the correct stock VAG main bearing bolt and someone hasn't  messed around with the engine before.

Noted.

 

 

13 hours ago, J.R. said:

Can anyone confirm that the offending item is the correct stock VAG main bearing bolt and someone hasn't  messed around with the engine before.

 

I am the 2nd owner of this car, I had it since it was 2 years old. I nor the dealer ever dropped the sump or been in here. I ordered a set of 10 bolts from Skoda and they are identical. 

is there a reason why this is so red compared to the other ones?

Yes, that's the copper backing, it's completely worn out.

Yep, that's totally knackered.

Oil starvation is how that happened, previous owner let the level drop too low and the bearings got starved during braking or cornering when the oil sloshed away from the pickup pipe, big ends have probably had it as well.