190 V6 thermostat housing - how long have I got

[Ps3000]

I am now fairly sure that the pipe next to the thermostat housing is the source of my minor leak (quite a bit of red staining behind it). I have a few trips planned so although I have the kit to fit new pipes/housing, I don't have time to fit it yet.

Assuming I keep an eye on temps/level any idea how long can I run this for before it fails totally and strands me?

[GAVIN]

I am now fairly sure that the pipe next to the thermostat housing is the source of my minor leak (quite a bit of red staining behind it). I have a few trips planned so although I have the kit to fit new pipes/housing, I don't have time to fit it yet.

Assuming I keep an eye on temps/level any idea how long can I run this for before it fails totally and strands me?

Got the kits in stock if you fancy a trip to the workshop & I'll do it whilst you wait..
Regards
Gavin

[Ps3000]

Many thanks for the offer - if I last the week :-) I may take you up on it.

[SD1too]

I am now fairly sure that the pipe next to the thermostat housing is the source of my minor leak .. how long can I run this for before it fails totally and strands me?
Hello John,

From my investigations and tests the 'O' ring will be the cause of your leak not the pipe, and you won't be stranded. I have the same problem at the moment and the lowering of the level in the expansion tank is slow and easily topped-up.

Simon

[Stag>75]

Many thanks for the offer - if I last the week :-) I may take you up on it.

If you can manage it I'm sure we would all like to see some photos of the old parts once removed. Some people report fatigue of the plastic. I went with Kaisers Aluminium housing so I don't expect to ever have these problems.

[DMGRS]

I do have the O Rings on their own, if needed:
CDU3858 - K Series / KV6 Thermostat Housing O Ring (http://www.dmgrs.co.uk/products/o-ring-k-series-kv6-thermostat-housing-cdu3858)

Sounds like these could indeed be your problem.

[Ps3000]

I do have the O Rings on their own, if needed:
CDU3858 - K Series / KV6 Thermostat Housing O Ring (http://www.dmgrs.co.uk/products/o-ring-k-series-kv6-thermostat-housing-cdu3858)

Sounds like these could indeed be your problem.

Thanks Matt - I've got the full kit sitting in the garage that I bought off you a few weeks back - just need to find the time - seems a bit daft not to fit it all while I'm there.

[Ps3000]

If you can manage it I'm sure we would all like to see some photos of the old parts once removed. Some people report fatigue of the plastic. I went with Kaisers Aluminium housing so I don't expect to ever have these problems.

Yes, I will take some before and after (and even some during) when I get around to it.

[Ps3000]

Hello John,

From my investigations and tests the 'O' ring will be the cause of your leak not the pipe, and you won't be stranded. I have the same problem at the moment and the lowering of the level in the expansion tank is slow and easily topped-up.

Simon

Thanks Simon - pretty sure that's what it's about - I'm only losing a tiny amount.

[Astraeus]

Thanks Simon - pretty sure that's what it's about - I'm only losing a tiny amount.

Word of caution


I recently fixed one for someone that was leaking a little. When I touched it to remove it literally fell apart into about six bits.
Change it as soon as you can

Chris

[kaiser]

When an O-ring is placed in position, the design is so that it is under compression from almost all sides, but especially from side to side.
The groove in which the O-ring is situated, is square, and it sits against a flat metal cylinder (flat as in cross section).
That means you are fitting a round O-ring in a square hole.

As the O-ring beds in, it exerts pressure on the wall, and pressure on the inside (the plastic groove) and it is relatively free to expand top and bottom, where there is space left. Once in service for a while, the o-ring gets harder and solidifies in it's allocated space, it becomes less elastic and rather solid and unable to act elastically.

What happens to the metal? nothing! What happens to the plastic pipe? it gets deformed, and starts bulging to the inside. It is not very noticeable, but if you look, it is there. That means even if everything else is in order with the plastic, and you just use another O-ring, that the space available to the O-ring is enlarged, and each subsequent replacement of O-rings get less and less purchase. The result is less and less service time for each subsequent change.

If you will be given a chance to experience this is doubtful, as the plastic is likely to disintegrate at a point. It seems a lot faster with newer plastic items (which seem different to the original issue) and it happens faster in hot climates. A failure can be sudden or it can be stealthy depending on many factors. The fact is you have a system which is compromised in many ways, and inherently increasingly unstable. Driving with this is fine if your gauge warns you in time. It is problematic, at best, if it does not.

In any case frequent checking is mandatory, and might save the day if vigilance is kept up, but it is of no use if you have a catastrophic failure that goes unnoticed.

[MrDoodles]

As others have said, it does depend on which part is actually leaking! :shrug:

If it is the O ring, then it will be gradual, however, if it's the pipe itself, it could go at any time, so get it changed a soon as you can! ;)

[chris75]

Word of caution


I recently fixed one for someone that was leaking a little. When I touched it to remove it literally fell apart into about six bits.
Change it as soon as you can

Chris

+ 1 . Exactly the same thing happened to me . The plastic just crumbled when I tried to remove it !

[SD1too]

When I touched it to remove it literally fell apart into about six bits.

The plastic just crumbled when I tried to remove it !
How strange. My car is of a similar age to yours, yet I've not experienced this. All I get is flattened 'O' rings.

Simon

[Ps3000]

OK - planned trip for tomorrow now off, so I can do the car. I have ordered the inlet manifold gaskets just in case - but should I do the "keyhole" method rather than disturbing them?

I have big hands and I can be a bit hamfisted, but the "keyhole" version looks preferable. On the other hand - is it really that much more hassle to remove the inlet manifolds?

Is it just me who thinks the KV6 is a thing of beauty? :getmecoat:

[kaiser]

The inlet manifold seals might well be in need of replacement. The inlet manifolds are a bit fiddly to remove. This is not the place to be ham fisted, and you need good tools, slim extensions with good reach and and a bit of flex.
Cheap heavy tools are not good.
I would be careful not to disturb any plastic items generally, but specifically the fuel rails, remove anything you can in situ. If you remove, it will almost guaranteed break something amplifying your problems.
When assembling, tighten the inlet manifolds firmly but not stupidly, and re-torque after a couple of days or weeks. These seals are thick and they do set. Any leaks here are amplified because of high vacuum from the inlets at low revs.
Oh, and be prepared to do this again, in the not too distant future!:D

This is clearly a case exceeding new O-rings, whichever way you look at it.:getmecoat:

[SD1too]

I have ordered the inlet manifold gaskets just in case ...
I know that most people don't because of the expense, but I would recommend investing in a torque wrench for the aluminium inlet manifold bolts. You'll only need a small one because the torque is 25 Nm and as Kaiser says, 3/8 in. drive sockets with wobble extensions are best.
... but should I do the "keyhole" method rather than disturbing them?
The two coolant pipes and thermostat housing are tightly interlocked so I don't believe you'll be able to remove them without breaking them into fragments using the keyhole method, which makes an awful mess and you don't want little bits of plastic dropping into the ports in the engine.

Simon

[Stag>75]

How strange. My car is of a similar age to yours, yet I've not experienced this. All I get is flattened 'O' rings.

Simon

Simon

I know there have been many threads on this topic and I believe many people have reported the plastic breaking down. I do believe Kaiser posted some photos some years back with the straight pipe showing cracks and I know people in Australia have certainly reported the plastic deteriorating although I can say that my car had done 70,000KMs but the plastic showed no signs of deterioration

As many people experienced issues beyond the O rings, I believe this is why Kaiser went to the effort to build an Aluminium one - as a permanent fix. And I know there have been many threads on that topic. I believe I read every thread on the topic before deciding to go with it, and if DMGRS (as recently posted) can supply a higher opening stat, then from my perspective the solution is clear. And no Kaiser has not paid me to post this.

John

[Ps3000]

Thanks again all - I do have a decent 3/8 drive socket set with a universal joint and a couple of wobble extensions, and a torque wrench, so I am in with a shout of not busting it all :-)

[chris75]

It's not just the thermostat housing that fails . In my own case it was the elbow pipe that broke up and dumped the coolant catastrophically . The thermostat housing appeared to be ok in-situ but did not survive being removed .
You might find this link helpful to show you what you have in store http://www.jimmcglynn.pwp.blueyonder.co.uk/zt/projects/thermostat/index.html

[dattrike]

Simon

I know there have been many threads on this topic and I believe many people have reported the plastic breaking down. I do believe Kaiser posted some photos some years back with the straight pipe showing cracks and I know people in Australia have certainly reported the plastic deteriorating although I can say that my car had done 70,000KMs but the plastic showed no signs of deterioration

As many people experienced issues beyond the O rings, I believe this is why Kaiser went to the effort to build an Aluminium one - as a permanent fix. And I know there have been many threads on that topic. I believe I read every thread on the topic before deciding to go with it, and if DMGRS (as recently posted) can supply a higher opening stat, then from my perspective the solution is clear. And no Kaiser has not paid me to post this.

John

The aluminium one is far better, I've got one fitted and my car now runs cooler at 87°c average, which I prefer. It also seems to warm up quicker as well.
I'm not getting paid either :thumbdown: :D

[minimutly]

Had my own episode of this recently, and was forced to tackle it one Sunday afternoon for fear of a catastrophic failure a long way from home.
As stated, you need 3/8 drive sockets, wobbles and extensions, and some patience.
I would recommend removing the front inlet manifold, and checking the tightness of the bolts clamping down the rear at least.
On mine, despite only being done 1 1/2 years ago, 35k miles, the (new kit) o rings were square, and showing signs of distress, however, it was the front inlet manifold that looked like was the culprit. Certainly the bolts were not tight enough, which backs up the suggestion these should be re tightened after a number of heat cycles (this is not easy, requiring the removal of the plastic plenum, which is why it never got done on mine).
So, had I know there was an aluminum kit I would have probably gone for it, but the issue of o ring distortion still remains, doesn't it?
One of the cause of the problems with this would seem to be the lack of support for the three pipes, if you move these around behind the rad you will see the elbow and the stat housing flexing - mine have a pair of cable ties holding them together and tied to the lifting bracket, hopefully this will help, but no doubt I will be back in there in a year or twos time..
Huw

[Stag>75]

So, had I know there was an aluminum kit I would have probably gone for it, but the issue of o ring distortion still remains, doesn't it?


Referring back to Kaisers post, O rings can deteriorate and they can distort to become square but the point he made is that the plastic pipe distorts and hence the O rings no longer hold the seal.

Some photos of the distortion and photos of brittle parts would be interesting to see. No doubt people break the parts (Especially the bent pipe) when removing but photographic evidence of obvious deterioration in the plastic parts would be interesting for all.

[SD1too]

In my own case it was the elbow pipe that broke up and dumped the coolant catastrophically .
Chris; in your last post you said that something collapsed when you touched it. Can you clarify exactly what happened please?
The thermostat housing appeared to be ok in-situ but did not survive being removed.
That's often the case but it's because the parts are tightly interlocked not because of a weakness in the material.

... but the issue of o ring distortion still remains, doesn't it?
:iagree: :wot:

One of the cause of the problems with this would seem to be the lack of support for the three pipes, if you move these around behind the rad you will see the elbow and the stat housing flexing ..
That's a new and interesting suggestion Huw. So moving the hoses from the radiator results in this flexing?

Referring back to Kaisers post ...the point he made is that the plastic pipe distorts ..
I've seen no evidence of that. I've fitted new 'O' rings to existing plastic parts and the leak has stopped for thousands of miles, which doesn't support that theory.

Simon

[chris75]

Chris; in your last post you said that something collapsed when you touched it. Can you clarify exactly what happened please?

Simon

None of my problems were due to excessive force ; I have a pathological hatred of plastic and always approach it with caution . :}
I was alerted to my problem by a pool of orange coolant under the car one morning (must have failed as I parked-up ! ) and when I checked in the vee there was a pond there . I removed all the manifolds for best access and could immediately see there was a little triangular piece missing from the bottom of the elbow ; this was found in the vee ! The hoses and fixing bolts were removed and the elbow fell off , leaving the lower spigot stuck in the block and needing to be prised out with a screwdriver tip , after plugging the waterway with a rag. It came away in pieces without using any force .
The thermostat appeared to be secure but was to be replaced anyway ,so had to come out . Plenty of plus-gas around the joint then started to gently twist it back and forth to see if it would loosen . It came away easily , but also left the bottom spigot behind in the block :eek:; back to the screwdriver tip !
With both parts , that portion of the plastic which sat in the block had undergone a radical change of composition and literally crumbled under finger pressure into gritty particles . The other end of the parts where they connected to the hoses were ok and seemed normal.
For the record , only OAT coolant had ever been used and the mileage at the time was about 85k miles . It was replaced with OE plastic parts from Rimmers and I don't regard 85k miles as bad for plastic parts , especially when subjected to great heat . We are told that rubber belts have a timed life ; so I would suggest do plastic pipes :shrug: I would also say that none of this crumbling was really a problem in doing the job , so long as you have new parts to fit !

[minimutly]

[QUOTE][
One of the cause of the problems with this would seem to be the lack of support for the three pipes, if you move these around behind the rad you will see the elbow and the stat housing flexing ..
/QUOTE]
If you try this, do it with the system full, you'll see what I mean. Every time you hit a bump, change gear, lift off, accelerate, turn a corner, the weight of water in these will be deflecting the plastic elbow and t stat.
If you waggle the pipes and watch the plastic bits you'll se what I mean.
Huw

[Bolin]

It's not just the thermostat housing that fails . In my own case it was the elbow pipe that broke up and dumped the coolant catastrophically .

This happened to me too!

Coolant temperature was a little higher than normal when sat in traffic, went down a little when on the move then started going up. Dived into a car park and as I stopped steam came out from the bonnet. Tried refilling after cooling but water was pouring into the 'V', so recovery time.

My elbow pipe developed a crack from the base lengthways to about 2/3 or 3/4 of the way along - I photographed this after removing just the engine cover, nothing else (slide cameraphone into the 'V'). When removing the elbow, the base broke away.

One of the cause of the problems with this would seem to be the lack of support for the three pipes, if you move these around behind the rad you will see the elbow and the stat housing flexing

Agree 100%!

That's often the case but it's because the parts are tightly interlocked not because of a weakness in the material.

Hmm, so if you fitted a new housing and elbow and removed it straightaway, would it break or not? I think it would be fine.:shrug:

If you try this, do it with the system full, you'll see what I mean. Every time you hit a bump, change gear, lift off, accelerate, turn a corner, the weight of water in these will be deflecting the plastic elbow and t stat.
If you waggle the pipes and watch the plastic bits you'll see what I mean.

Yes, totally agree:}, I am sure this was the cause of my elbow cracking from the base. The time of failure may depend on how many bumps you have driven over (so more flexing) and time exposed to heat (my plastic pipes did look like they had suffered from micro-cracks, presumably due to heat).

I might try to take some photos of my old bits to show some of the micro-cracking.

I fitted Kaiser's housing, and am confident that the hose weight will not break it! As for the o-rings, we will see - but I did add a whole load of sealant around them, which I may or may not regret in the future. Time will tell.:shrug:

[SD1too]

Thanks Chris and Colin for your evidence regarding the elbow pipe breaking up. When I experienced coolant loss for the first time, my elbow pipe fractured upon removal but I thought that it was my fault. Now that you both have reported the same problem, I'm rethinking this.

When I bought a replacement I noticed that MGR had redesigned it. The fixing lug was thicker and was strengthened with a brace if I remember correctly. I know that I had to have a longer fixing screw. So it looks as if a weakness was identified and dealt with, but it hasn't solved the problem. :o

Simon

[Bolin]

Interesting, not sure if the fixing lug would have had any effect on my pipe - I'll take some pictures of the remains in the next day or so. My pipe had split in-situ, and I don't think the lug could have prevented this, but it's worth having a look at.

I still think Kaiser's housing is the way forward, shame that the 88 degrees thermostat that fits it is no longer available - luckily for me I have one inside it and one spare:}

[Stag>75]

[QUOTE][
One of the cause of the problems with this would seem to be the lack of support for the three pipes, if you move these around behind the rad you will see the elbow and the stat housing flexing ..
/QUOTE]
If you try this, do it with the system full, you'll see what I mean. Every time you hit a bump, change gear, lift off, accelerate, turn a corner, the weight of water in these will be deflecting the plastic elbow and t stat.
If you waggle the pipes and watch the plastic bits you'll se what I mean.
Huw

I recall reading an old post about a proposed bracket that MG Rover engineers had designed but it I cannot recall whether it was for a future implementation. I cannot recall who posted it and when it was posted, but I found it in all the searching I did on the topic.

[Stag>75]

I still think Kaiser's housing is the way forward, shame that the 88 degrees thermostat that fits it is no longer available - luckily for me I have one inside it and one spare:}

This is what I was referencing in my earlier thread.

http://www.dmgrs.co.uk/products/thermostat-for-kaiser-kv6-metal-housing-87-c-vernet-6773-equivalent

So assuming that is 87 degrees and the correct length etc then there IS a solution. Just need Kaiser to offer those as an option then I think everyone would be happy. Well almost everyone :D

[DMGRS]

I agree that the Kaiser item is the 'ultimate' fix for this problem - I've had a look at one and they're a great bit of kit. :)

[Ps3000]

Matt - glad you've popped up - unfortunately no sign of my inlet gaskets, I got a note to say they were posted on 15th (presumably 16th). I usually get lightning service from you (and my local RM are excellent) so slightly puzzled :-)

[Ps3000]

Ok, as you were, received now.

[DMGRS]

Ok, as you were, received now.

Sorry - I missed the above post. Glad they arrived OK in the end. :)

[Bolin]

This is what I was referencing in my earlier thread.

http://www.dmgrs.co.uk/products/thermostat-for-kaiser-kv6-metal-housing-87-c-vernet-6773-equivalent

So assuming that is 87 degrees and the correct length etc then there IS a solution. Just need Kaiser to offer those as an option then I think everyone would be happy. Well almost everyone :D

Ah, 87 is close enough to 88, good stuff :)