Coolant issue.

[ClassicChimaera]

Not sure what to think of this one. Driving along, temps a tad low after 15 miles I can hear and almost feel a prounounced tapping coming from engine bay so pullover. The engine switched off clunks/taps like a hammers being hit off it. Seriously violent action with palm placed on Plenum. It stops. Re start engine, Rev it, hold revs for awhile, fans kick in and out, no tapping clunking sounds, drive car,,, hear water rushing in or out of heater matrix, heaters hot,
Carry on a bit more, hear prounounced tsppimg so pullover,, engine running feel hose from engine to swirl pot, clunking and what feels like sudden rushes of water and air, these clunks move the engine. Switch off. Leave it for a few minutes at most, fire up and drive 10 miles home with no noises and again at home no huge ticking as engine cools and no clunks from engine.
Long story short I'm hoping this is air in the system rather than what felt and sounded like metal clashing against each other. Is this a sign of liner problems.
Very strangely when I'd first noticed the tapping and stopped the engine, no tapping at this point I unscrewed the expansion cap and barely any pressure released?!!
Did the same thing the second time and there was pressure as you'd expect. Hoses don't feel to firm or bulging but are firm.

Any ideas guys.
I've never heard or seen an engine make such odd noises.
The noises continue when engines off so not mechanical but it feels like it and the engine shudders from the force.

Edited by ClassicChimaera on Thursday 30th March 07:50

[Discopotatoes]

get a sniffer on it an check for hydrocarbons, also drop the oil and check for particles, you may have a slipping liner its not unheard of

[ClassicChimaera]

It's a distinct possibility. Jesus wept!

[Discopotatoes]

if you can get it to repeat get a screwdriver against your ear and place it on the inlet manifold near as you can to the cylinders do each cylinder you should be able to hear which cylinder is slipping or narrow it to a bank

[ClassicChimaera]

Discopotatoes said:

if you can get it to repeat get a screwdriver against your ear and place it on the inlet manifold near as you can to the cylinders do each cylinder you should be able to hear which cylinder is slipping or narrow it to a bank

I'm convinced it's a slipped liner now

The noises when engine was running sounded entirely mechanical and loud, fk st crap!

I'm vainly hoping because the clunking carried on when engine was off its cooling related but the more I think about it, it's both! I'm assuming liner movement could add pressure into the water system!

I'll check oil and water first thing then get some checks done.
I'm not very confident this will be a simple Air in the system problem.
So engine gets hot, liner sllips and mechanical noise ensues.
Engine cools and liner regains grip??? Why has it gone silent again. I drove a good 10 miles with no tapping and engine was very quiet. Temp gauge never got above 90. Hmmm!

Has anyone witnessed the sound of a slipped liner in a serp engine. How would you describe it.
It's obviously serious because the engine vibrated and the clunks resonated through it.

On another note, I noticed my plenum was very cool to touch after running in wind then instantly putting hand on it, it's usually hot, or it is when I've placed my hand on before but it could just be heat soak when engines stopped!

I feel like Mclaren, might aswell give up

[Richard 858]

Jesus Alun, I certainly hope things aren't as serious as you fear!!

[Discopotatoes]

ClassicChimaera said:

Discopotatoes said:

if you can get it to repeat get a screwdriver against your ear and place it on the inlet manifold near as you can to the cylinders do each cylinder you should be able to hear which cylinder is slipping or narrow it to a bank

I'm convinced it's a slipped liner now

The noises when engine was running sounded entirely mechanical and loud, fk st crap!

I'm vainly hoping because the clunking carried on when engine was off its cooling related but the more I think about it, it's both! I'm assuming liner movement could add pressure into the water system!

I'll check oil and water first thing then get some checks done.
I'm not very confident this will be a simple Air in the system problem.
So engine gets hot, liner sllips and mechanical noise ensues.
Engine cools and liner regains grip??? Why has it gone silent again. I drove a good 10 miles with no tapping and engine was very quiet. Temp gauge never got above 90. Hmmm!

Has anyone witnessed the sound of a slipped liner in a serp engine. How would you describe it.
It's obviously serious because the engine vibrated and the clunks resonated through it.

On another note, I noticed my plenum was very cool to touch after running in wind then instantly putting hand on it, it's usually hot, or it is when I've placed my hand on before but it could just be heat soak when engines stopped!

I feel like Mclaren, might aswell give up

can you get a video up of the sound when it happens?

[ClassicChimaera]

I'm gonna write a list of the worst things that can go wrong and tick them off as I go along Richard
Cracked block will be in the next breath knowing my luck.

It's such a quiet engine normally.
At first I thought I had a lifter falling to pieces by the sounds of it.
No point me guessing.
You know where I'm going tomorrow. It's a liner surely cos it's gone tight and stops making such horrendous noises,what else could come and go like that.
That's me off the road for sometime if this is the reality.
Unbelievable.

[Discopotatoes]

ClassicChimaera said:

I'm gonna write a list of the worst things that can go wrong and tick them off as I go along Richard
Cracked block will be in the next breath knowing my luck.

It's such a quiet engine normally.
At first I thought I had a lifter falling to pieces by the sounds of it.
No point me guessing.
You know where I'm going tomorrow. It's a liner surely cos it's gone tight and stops making such horrendous noises,what else could come and go like that.
That's me off the road for sometime if this is the reality.
Unbelievable.

fingers crossed for you, but get a sniffer test done if a liner is slipping and pressurising the water jacket this will show up

[ClassicChimaera]

Discopotatoes said:

can you get a video up of the sound when it happens?

I can try but it's intermittent or not at all.
I'll take it over to engine builders tomorrow and we'll find out.,,,,,, that it's fked.

[ClassicChimaera]

Discopotatoes said:

fingers crossed for you, but get a sniffer test done if a liner is slipping and pressurising the water jacket this will show up

Yep. It's obvious now I think about it. 20,000 miles at grandad speeds. Jeez.

I might aswell prepare myself for bad new and try and find some positives from this. I've come to love my RV when for years I thought they were st,,,,, FFS

I have the feeling it's more than one of them, coming from left and possibly right bank too going by my ears.
Ok on Saturday I went 25 miles with the roof off, I heard this noise but thought it was the flipping rear screen settling and creaking. By the time I'd slowed from 70 mph to 30-40 in town so I could hear properly it had settled and didn't do it so assumed I was right. How wrong was I.

I wonder if Dom needs a van driver for a month, does he do credit come on ,,, that is funny

Edited by ClassicChimaera on Wednesday 29th March 22:14

[Discopotatoes]

ClassicChimaera said:

Discopotatoes said:

fingers crossed for you, but get a sniffer test done if a liner is slipping and pressurising the water jacket this will show up

Yep. It's obvious now I think about it. 20,000 miles at grandad speeds. Jeez.

I might aswell prepare myself for bad new and try and find some positives from this. I've come to love my RV when for years I thought they were st,,,,, FFS

if you do find its a liner and if you can stretch to it top hats are the way forward, I've had this on my old P38 just after i bought it, 70000mile later and a couple of overheats (due to blocked rad and failed viscous fan) and a HG failure later the block was still good as gold, a days work replacing the HG's and getting rid of a airlock and was back to normal, goes to prove this is a no brainer when building a lump from scratch.

[ClassicChimaera]

Discopotatoes said:

if you do find its a liner and if you can stretch to it top hats are the way forward, I've had this on my old P38 just after i bought it, 70000mile later and a couple of overheats (due to blocked rad and failed viscous fan) and a HG failure later the block was still good as gold, a days work replacing the HG's and getting rid of a airlock and was back to normal, goes to prove this is a no brainer when building a lump from scratch.

Which is a very good point, and very very annoying that I didn't have them done. I knew nothing about these engines then!!

It might be a broken spring or rocker for all I know but the symptoms do appear classic liner problems.

I do not rev this engine above 5000 revs and that's not often so id be surprised if it's valve train.

This focuses the mind slightly! Buuuuuummmmer

[Steve_D]

Not saying this is not a liner issue but the noise continuing after the engine is off is more likely to be localised boiling and the noise is the steam pockets charging through the system.
Again this would not be rocker or lifter related if the noise continues.

Steve

[ClassicChimaera]

Steve_D said:

Not saying this is not a liner issue but the noise continuing after the engine is off is more likely to be localised boiling and the noise is the steam pockets charging through the system.
Again this would not be rocker or lifter related if the noise continues.

Steve

Thanks for this clarity Steve.
This is my only hope that the noises I heard whilst engine WAS running are this localised boiling that I can feel when engines switched off, carries on for 10-15 seconds then settles. water/air/pressure on the hose after the thermostat felt violent.
I also heard the sound of water rushing through the heater pipes in the pass footwell whilst driving which I've never had before, then the ticking.

Thanks for the replies guys, helps make sense of it all.


My temp gauge took to long to get upto temp! Should have known right then something wasn't right. Tut tut.

Edited by ClassicChimaera on Wednesday 29th March 23:31

[Discopotatoes]

ClassicChimaera said:

Steve_D said:

Not saying this is not a liner issue but the noise continuing after the engine is off is more likely to be localised boiling and the noise is the steam pockets charging through the system.
Again this would not be rocker or lifter related if the noise continues.

Steve

Thanks for this clarity Steve.
This is my only hope that the noises I heard whilst engine WAS running are this localised boiling that I can feel when engines switched off, carries on for 10-15 seconds then settles. water/air/pressure on the hose after the thermostat felt violent.
I also heard the sound of water rushing through the heater pipes in the pass footwell whilst driving which I've never had before, then the ticking.

Thanks for the replies guys, helps make sense of it all.


My temp gauge took to long to get upto temp! Should have known right then something wasn't right. Tut tut.

Edited by ClassicChimaera on Wednesday 29th March 23:31

lets hope you have a dodgy hose or jubilee clip or better still a bad expansion tank cap
allowing a slow weep, water out air in then causing an overheat, would be an easy fix

[ChimpOnGas]

Don't rule out a failed water pump Alun,

The pulley can be turning, but if the impeller isn't turning inside the pump it could potentially give you the symptoms you describe.

Just an idea and worth checking I'd say.

Good luck with it mate, here's hoping it's something simple and relatively cheap like the water pump, and not the dreaded liner slip.

[ClassicChimaera]

Thanks for the words guys, loose hose, I'd thought of that one too.
Now a few weeks back I replaced steering arm joints, loosened small water pipe that goes to the metal tubed bit to swing the clip out the way, tiny amount of coolant seepage and nipped up. Maybe drawing air there. But I'm not using water!

AND I have a recently purchased expansion cap. About a year or so old!
Genuine VW part so? I'll put the old one back on and try it
I'm about to down my coffee and have a look at it in daylight.
Feeling pensive and deeply miffed!

Water pump Dave replaced a year ago, I did imagine a broken impeller. Cold start this morning and I'll listen with a driver to ear.

Edited by ClassicChimaera on Thursday 30th March 07:41

[ClassicChimaera]

No 2 plug.

[ClassicChimaera]

You'll probably have to press on pic then again so it scrolls down to see it clearly. Ipad !

Something's not been right for awhile,, black plugs less than 3000 miles ago when these were installed!

Those ( what appear to look like metal shards) are welded to the plug!

Water blue, oil clean, no loss of coolant, engine fires and runs quiet. Long screwdriver to ear on inlet manifold at ports, top of rockers, all sounds good, no tapping. Water pump sounds normal with driver to ear, rises and and falls with revs.

I've not warmed the engine yet as I've just pulled this plug. Not sure I should either!

this is for people's info and debate.
I will discuss this with engine builder. What a nightmare.
Any input is very welcome. It's a learning curve.

I don't want this to become a witch hunt so keep personal views aside please. This is serious st and I need technical advice only.
Thanks Al