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Old 13th March 2018, 15:15   #21
aReallyNiceCar
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Hello Mr Kaiser,
Don't make me read through your link.
How does it end.?
Were you able to get them made cost-effectively.?
Regards,

Meanwhile....... You & Arctic
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Old 13th March 2018, 16:40   #22
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Originally Posted by aReallyNiceCar View Post
Hello Mr Kaiser,
Don't make me read through your link.
How does it end.?
Were you able to get them made cost-effectively.?
Regards,

Quote:
Meanwhile....... You & Arctic
Dan there will be no pillow fighting from me, i respect all Kaiser input to this forum, and his ideas, as i stated above i have one of his thermostats in waiting should i need it in the near future
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Old 13th March 2018, 21:18   #23
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So I've just double checked the service records I keep and I was a little out earlier. Although the repair dates don't represent the failure dates as I did nurse things along with regular top ups for months here's when I've been changing things:

July 2015, 72,500 miles - new thermostat pipes and O-rings.

December 2015, 78,600 miles - new O-rings

June 2017, 88,500 miles - new viton O-rings, supported thermostat and banana pipe.

So my 3 sets of O-rings have managed 6k in 5 months, 10k in 18 months, and now 4.5k in 9 months. I'll probably get to 7k in 12 months with the current set.

I really don't want to go down the k-seal/radweld route, but I have wondered if it could work from the outside. If I could pour a small amount into the gap above the o-ring, where I can see the coolant at the moment could that work?

Alternatively I've got some fernox lx-s (leak sealer) for the central heating which I'm tempted to try.

These are bodges I know, but doing a proper job doesn't seem to be working.
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Old 13th March 2018, 23:12   #24
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Originally Posted by kaiser View Post
Ha ha, OK, so you have one car that never brakes down and never has any trouble.
I didn't say that, as readers of my posts will be able to see.
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Originally Posted by Randyjim View Post
I really don't want to go down the k-seal/radweld route ... These are bodges I know, but doing a proper job doesn't seem to be working.
Jim; like you I thought I had done "a proper job" but my 'O' rings kept flattening. Rather than adopt desperate 'bodger man' techniques I realised that I had not yet discovered the cause of the problem. That's where the real solution lies.

In your shoes I would renew the 'O' rings using the genuine MGR part. I'm not sure that Viton is a suitable material for this application. Resistance to antifreeze and temperatures in excess of 115°C are required and when I researched the options some years ago EPDM was the best choice, not Viton.
You've already got the housing with the three supporting lugs, you've tightened the bolt to the recommended torque and you've set the straight pipe clips correctly. Remember that there are many V6s around which do not suffer this leakage problem (including those using OAT) so it must be something that we are doing!

Simon
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Old 13th March 2018, 23:24   #25
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Dan there will be no pillow fighting from me, i respect all Kaiser input to this forum, and his ideas, as i stated above i have one of his thermostats in waiting should i need it in the near future
I'll assume from your post, that the link Kaiser sent me (which I've not read through) ends happily with his design working well & at a satisfactory retail price.?

... & that's why I put it down as a & not .!!!!!

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Old 14th March 2018, 07:38   #26
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Originally Posted by aReallyNiceCar View Post
Hello Mr Kaiser,
Don't make me read through your link.
How does it end.?
Were you able to get them made cost-effectively.?
Regards,

Meanwhile....... You & Arctic
There are many ways to read a book. One is to follow the story and understand what is going on.
In this modern world you can also, skip as required and jump towards the end.

It depends on what you are looking for, the score or the game!
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Old 14th March 2018, 13:15   #27
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Simon,

I've removed some very flat 'OE' rings on a couple of occasions, so I don't believe these are fit for the job. At least not without finding a reliable supplier with genuine OEM product.

I recall that your EPDM experiment didn't end well either.

As I stated in my original post, I believe the leak is due to a slightly damaged bore, so this is the problem that I'm seeking a resolution for, and not the wider shortcomings of the design.
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Old 14th March 2018, 14:21   #28
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Originally Posted by Randyjim View Post
Simon,

I've removed some very flat 'OE' rings on a couple of occasions, so I don't believe these are fit for the job. At least not without finding a reliable supplier with genuine OEM product.

I recall that your EPDM experiment didn't end well either.

As I stated in my original post, I believe the leak is due to a slightly damaged bore, so this is the problem that I'm seeking a resolution for, and not the wider shortcomings of the design.
The elastomer selection is a compromise, the manufacturer is caught between a rock and a hard place when it comes to selection and engineering.

In my industry we can only ever contemplate a double o-ring set up due to the consequences, but we are not selling low cost consumer items such as cars that are built to a price much like washing machines etc, where the costs are calculated down to the last washer hence only one o-ring used.

The type of elastomer selected for the thermostat assembly appears to be a EPDM material of relatively soft compound (shore perhaps 70 or so?). This will work well at low temp but also at high temps and will not take a set when compared to a harder o-ring such as duro 95 which suffers at colder temps but will have more resistance to failure at high temps and pressures.
The issue with the cooling system is the pressure is really low at 15psi and getting an o-ring to energise at low pressure and low temp can be challenging.

With EPDM you could argue that would be a better selection as when exposed to hydrocarbon the elastomer swells up significantly and would actually help close the extrusion gap between the materials. however a cooling system should not contain hydrocarbon unless the head had failed, but worth discussing anyway. Have you seen the EPDM coolant hoses on a car with failed head gasket where oil is in the cooling system, just observe the hoses and see how swollen they become.

I think MGR's engineering selection of relatively soft o-ring makes for relatively easy assembly into the bore of the component and will provide a long term seal, but as with age and as you have experienced the o-ring takes a set any scratches in the components can have a marked effect the o-rings performance. Unfortunately they fitted all o-rings dry which does not help. I have seen dry o-rings rolling upon fitting and leading to all kinds of leaks down the line.

Kaiser's thoughts on trying to source a slightly larger o-ring either in cross section or OD might be the most realistic option for you, and with the addition on Dow Corning DC111 silicone grease used upon assembly would give the best chance of a decent seal. The grease not only aids disassembly but long term exposure issues on elastomers due to hot coolant and allegedly exposure to OAT which I have never seen to date. A wee bit more cleaning up of the surface might be worth a punt too. With plastic components one cannot discount the fact the pin end itself maybe distorted leading to increased extrusion tolerances between pin and box. It would have helped if MGR or their suppliers had lined the plastic components with a metal sleeve to help avoid this, but again they are not different to any other manufacturer in the industry where a shaving a few pence off can make the difference when selling by the millions.
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Old 14th March 2018, 15:11   #29
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I've removed some very flat 'OE' rings on a couple of occasions, so I don't believe these are fit for the job ...I recall that your EPDM experiment didn't end well either.
That’s right; both MGR OEM and EPDM ‘O’ rings flattened. That told me that it is not the material which is at fault, therefore it is not safe to conclude that the ‘O’ rings are not “fit for the job” particularly as many V6 owners have not had this problem at all!

Also Jim, I have found the notes obtained from the ‘O’ ring company which I used. They said that Viton is rated for use with water only up to 100 deg. C which, of course, leaves insufficient safety margin on a cooling system which regularly reaches that temperature. For that reason alone I would recommend that you return to the MGR OEM ‘O’ ring.

Quote:
Originally Posted by Lovel View Post
Kaiser's thoughts on trying to source a slightly larger o-ring either in cross section or OD might be the most realistic option for you ...
I tried a slightly larger ‘O’ ring Gary (32.92 mm ID x 3.53 mm cross section) and my thermostat housing was written off when attempting to fit it. So I would not recommend that approach.

Simon
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Last edited by SD1too; 14th March 2018 at 15:19.. Reason: Adding information
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Old 14th March 2018, 21:22   #30
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Do we know what the OE ring material is? Of the failed OE rings I've removed they were a mixed bag of different discolorations and deformations so I'm not confident that there's a reliable supply made from the same material. As I've experienced with waterpumps recently, OE doesn't necessarily mean quality unfortunately, and there is more than one source.

This is the reason I looked to O-rings suppliers and I did quite a bit of reading, and there's some conflicting information out there. Thinking back, I did think I was taking a punt close to the temperature limit with the Viton, but Simply Bearings actually list Viton with a similar temperature tolerance to EPDM and having read about Simons results with EPDM I believed it should be good enough. I think I'd read that Viton was ok with water up to 120deg, so with coolant (not water) at 90deg it should have been ok, at least better than the suspect 'rubber' OE parts I've used previously.

If I can find a reliable source of OE spec O-rings I'll happily try this, and hopefully with the supposedly more rigid pipe work it'll give good long term results.

I have made enquiries about Aflas/FEPM O-rings, which should be even more tolerant of high temp OAT than EPDM or Viton, so I'll let you know how that goes.

With respect to oversize O-rings, what do you think the potential of a 1-1/2" x 1/8" (31.34mm x 3.53mm) would be? It's a little thick and a bit narrow on the ID, but with a little stretch to the nominal 32.5mm would thin down a little closer to the nominal 3mm. I know this introduces another stress into the equation, but could it work?

Simon, what spec are you currently using, and what do you think caused the failure on your epdm rings?
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