Water Leak Advice

[marinabrian]

Originally Posted by kaiser

Simon. You are impossible. You have experienced a small fraction of all possible scenarios, and to you that that appears like the whole universe.
I have had thermostat housings break, in several pieces, crumble like a biscuit, split in a seam and break at the O-rings plus failures at the weld on the housing. These parts can be a real pain in the proverbial.

To blame this only on O-rings is -- well, ---- not very smart.

And your question about pressurising the cooling system with or without the manifold??? What manifold are you talking about? and why?

You are starting to work on my nerves, I would like to remain polite and respectful, but I am getting to the point where I find it difficult.

Sorry that doesn't apply to Simon, if he hasn't experienced it himself personally, or a particular component has not failed on his car, then it is impossible to fail on any other car similar to his own.

Simon describes the symptom of his own leaks being caused by the o rings "flattening" this is known technically as compression set.

He cannot relate this failure type to incompatibility of the o ring elastomer material and the fluid it comes into contact with, but that along with thermal cycling is exactly what causes compression set.

Not as Simon incorrectly diagnoses, relative movement between the two sealing faces.

He also suggests lubricating o rings during fitting with washing up liquid, excellent advice if you wish to trap corrosive salts next to an aluminum component

Oh and don't forget, he is a master at discounting real life experiences of others far more skilled than himself, take his questioning of Jules for instance, he has more knowledge of the KV6 engine than Simon will ever gain, even if he lives another ten lifetimes.

Just humour him, he does have some good advice at times, but cannot accept when he is totally wrong

Brian

[SD1too]

Originally Posted by marinabrian

Simon describes the symptom of his own leaks being caused by the o rings "flattening" this is known technically as compression set .... He cannot relate this failure type to incompatibility of the o ring elastomer material and the fluid it comes into contact with, but that along with thermal cycling is exactly what causes compression set.

This is repetition of your post no. 8. Please see my reply: post no. 9.

... take his questioning of Jules for instance, he has more knowledge of the KV6 engine than Simon will ever gain ...

Let’s see what Jules’ reply reveals shall we.

Simon

[marinabrian]

Originally Posted by SD1too

This is repetition of your post no. 8. Please see my reply: post no. 9.

Let’s see what Jules’ reply reveals shall we.

Simon

Simon failure of the type you describe is not attributable to relative movements between the two components.

So your theory of clip positioning is complete nonsense, and that is a simple fact

Brian

[SD1too]

Originally Posted by marinabrian

So your theory of clip positioning is complete nonsense, and that is a simple fact

Why do you think the straight pipe was designed with two clips in grooves, allowing movement within as well as a tightening facility?

Simon

[marinabrian]

Originally Posted by SD1too

Why do you think the straight pipe was designed with two clips in grooves, allowing movement within as well as a tightening facility?

Simon

To allow for the differential expansion rates of two dissimilar materials used I would imagine Simon, however compression set of o rings is not a result of abrasion as you seem to imply, it is a symptom of incompatibility between the o ring media, and the fluid it is sealing against.

This is a fact, not anecdotal "evidence"

Brian

[SD1too]

Originally Posted by marinabrian

To allow for the differential expansion rates of two dissimilar materials used I would imagine Simon...

If that’s the case then why doesn’t the curved pipe and the thermostat housing need clips?
Secondly, the size of the grooves on the straight pipe is far too large just to compensate for material expansion.
Sorry Brian; very unconvincing.

... however compression set of o rings is not a result of abrasion as you seem to imply, it is a symptom of incompatibility between the o ring media, and the fluid it is sealing against. This is a fact, not anecdotal "evidence"

As I have already said to you Brian, why is it then that many V6s using 50% concentration OAT do not suffer ‘O’ ring leakage? I would like you to attempt to answer that and not keep repeating the same mantra.

No word from Jules yet on his pressure test. I expect he’s very busy. Maybe he’ll have time to explain at the weekend.

Simon

[kaiser]

Originally Posted by SD1too

If that’s the case then why doesn’t the curved pipe and the thermostat housing need clips?
Secondly, the size of the grooves on the straight pipe is far too large just to compensate for material expansion.
Sorry Brian; very unconvincing.

As I have already said to you Brian, why is it then that many V6s using 50% concentration OAT do not suffer ‘O’ ring leakage? I would like you to attempt to answer that and not keep repeating the same mantra.

No word from Jules yet on his pressure test. I expect he’s very busy. Maybe he’ll have time to explain at the weekend.

Simon

The answer is very simple.
The thermostat housing and the curved pipe are bolted in place in addition to the O-ring fixtures.
The straight pipe is short enough to be manipulated in place by pushing fully
home one end while fitting, but so short, that if that position is not changed in situ, the O-ring will risk loosening grip, as it will be deeply inserted one end, and on the insertion cone at the other.
Having to fit the clamps to the pipe will force an installer to move the straight pipe to a middle position, where the two groves for the clamps will be fully visible both ends , and both O-rings provide maximum efficacy by being placed on the concentric parts of the inlet/outlet.

This is all there is to it.!

[marinabrian]

Originally Posted by SD1too

If that’s the case then why doesn’t the curved pipe and the thermostat housing need clips?
Secondly, the size of the grooves on the straight pipe is far too large just to compensate for material expansion.
Sorry Brian; very unconvincing.

As I have already said to you Brian, why is it then that many V6s using 50% concentration OAT do not suffer ‘O’ ring leakage? I would like you to attempt to answer that and not keep repeating the same mantra.

No word from Jules yet on his pressure test. I expect he’s very busy. Maybe he’ll have time to explain at the weekend.

Simon

Simon, the same o rings are used in the 4 cylinder K Series thermostat housing, and how about this for a test run, 374,000 miles without a single leak on my 214

The only difference being it has been filled with blue antifreeze in the entire time I've owned it.

Not to mention the cylinder head gasket I fitted at 22,000 miles is still fitted at 398,000 miles.

So what does that say?

Anecdotal evidence maybe, but it certainly beats the hell out of your theory

Compression set as an o ring failure model is caused by two main factors, excessive thermal cycling or incompatibility between the material the o ring is manufactured from, and the fluid it is supposed to be sealing against.

If relative movement between the o ring and it's sealing faces were to blame, the o ring would have failed with visible abrasion marks, this is clearly not the case, so you are incorrect in your theory about movement.

Surely even you can see the folly of your own argument ?

In regard to the question of the housing and the elbow pipe being secured with a bolt, if your theory is to be believed, the o rings in this position should show no sign whatsoever of compression set, so is the case? and do the leaks stem from only the straight section of pipe?

There are plenty of cases where the housings have broken due to embrittlement caused by the corrosion inhibitor contained within OAT coolant, you even questioned the actual research carried out by the injection moulders of the parts into the effect of OAT, dismissing it because it had been carried out at an elevated temperature.

You should really think about it logically, elastomer component failure was comparatively rare prior to the widespread introduction of OAT antifreeze, but widespread post introduction.

That in itself speaks volumes

Brian

[SD1too]

Brian,

You’re very keen to dismiss my theories yet you have no answers to the evidence I’ve given in post no. 9 which disprove your claims, nor have you given a credible reason of your own to explain the presence of the straight pipe clips. To borrow your own phrase: that, in itself, speaks volumes.

My clips theory is currently under evaluation on my engine. It will take some time to find out if I’m right or wrong. Please be patient.

Simon

[marinabrian]

Originally Posted by SD1too

Brian,

You’re very keen to dismiss my theories yet you have no answers to the evidence I’ve given in post no. 9 which disprove your claims, nor have you given a credible reason of your own to explain the presence of the straight pipe clips. To borrow your own phrase: that, in itself, speaks volumes.

My clips theory is currently under evaluation on my engine. It will take some time to find out if I’m right or wrong. Please be patient.

Simon

I can be as patient as you like Simon, the exact same O rings fitted to the thermostat housing in my 214 are still completely leak free after almost 400,000 miles in service, the only difference being they have never been subjected to OAT antifreeze and it's plasticising qualities

Nothing however have you said thus far disproves my theory surrounding the negative effects OAT has on elastomer seals.

You can call it what you wish, but there must be some correlation between the widespread introduction of OAT, and the exponential increase in elastomer seal failure, this is an observation based upon real life experience, and why I run antifreeze solution containing silicate based corrosion inhibitors

Brian