Kv6 new thermostat leaks?

[SD1too]

Originally Posted by trikey

... age and OAT coolant does no favours to the material that the thermostat housing and particularly the elbow pipe are made from.

Hi Andy,

I'm afraid that age and OAT antifreeze were the clutches at straws which motivated me to find out the real reason.

My straight pipe is the original, now 22 years old. My curved pipe is 12 years old and I've never had leaks from either of them so the age theory doesn't hold water!

OAT isn't the issue either otherwise my straight pipe would have failed after 22 years exposure to it! Many more members also use 50% OAT and have never had leakage.

Simon

[Aidan Collingwood]

Dear All Members,

Thank you very much for all the welcomes and advice. It's a very helpful and welcoming forum.

I think that for cost reasons, I cannot justify stumping up for a metal thermostat - even if for future peace of mind - if it's just the O-rings which have failed. The cost of metal parts plus the breathtaking year's road-tax for a 2.5 V6 are worth more than double what the seller has been offered by a certain indiscriminate car-buying website, upon whose price I shall nevertheless base my offer to the seller, should I proceed.

To summarize all the advice I've received:
1) If thermostat housing/pipes have not actually failed, suspect/inspect and replace O-rings, and pay close attention to the serrated clips when reassembling.
2) If at all possible, try to get the "four lug" plastic thermostat housing as a replacement if a new housing is indeed required. (Trying to identify and actually buy a suitable thermostat itself seems to be another kettle of worms, but I'm assuming the "four lug" thermostat housing sold in the UK has the correct thermostat inside?)
3) Thoroughly clean the thermostat housing and engine/water pump areas where the thermostat and pipes interface/connect.
4) Flush engine of all coolant several times & check for a balanced performance of interior blower motors; driver vs. passenger side.
5) Keep and eye on coolant levels FOR EVER whilst owning a Rover 75...

Right now I'm also mulling over the "death rattle" that I heard emanating from the top/rear of the engine whilst idling at operating temperature. I've read the buying guides and troubleshooting info on this forum about the possible V6 issues and this car seems to have at least two; the death rattle and leaky coolant in the V... plus a very droopy headlining (Tourer version), door mirrors that don't fully adjust, and the car sounds quite noisy inside whilst on the move which suggests an exhaust leak or a loose metal brace above the headlining. The car has done about 134 000 miles and is being sold by the original owner's wife.

I still haven't made up my mind about buying this car, but even if I decide not to, I hope that this thread serves to clarify the thermostat issue a bit more for other people.

Regards,

[vitesse]

Even though I’ve been on this forum for a good while, I share your confusion about these new thermostats and I don’t think we’ve got a definitive answer yet. Not so long ago the rear upper arms were a similar subject of discussion, I believe that question has been finally resolved by DMGRS listening and then commissioning their own branded upper arms. If I needed a set, there’s no way I would take a chance on ebay, or even Xpart ones as there’s no guarantee that they’re up to spec. I wouldn’t be surprised to hear news of branded DMGRS thermostats in the near future, or as soon as they can assure us of a proper 88 deg thermostat.

At the moment I wouldn’t buy a new thermostat anywhere (including DMGRS) and would rather re-use an old one I’ve got up in the attic.

There have been several promises of solutions to the death rattle upper manifold through the years, all have fallen flat. I’m currently examining a new Chinese KV6 manifold I’ve got on the workbench.

Regards

PS I'd suggest adding "replace inlet manifold gaskets" to your list, very easy while doing the thermostat and cost little.

[biffa75]

I'm hoping to finish putting my 75 back together tomorrow with the new thermostat supplied my summit garage.

Although it doesn't have the four lugs, if it opens at the correct temperature, would this not be preferred over a thermostat without the added supporting legs seeing how it is the original design?

If the thermostat does open at the correct temperature, I would in my honest opinion, purchase the thermostat housing from summit garage in dudley Simply because it works I aren't sure of any other parts suppliers that may have a correctly operating thermostat. E car parts and dmgrs thermostats people are having issues with them opening too early.

Shame we don't know who the manufacturer is of the four supporting legged type thermostat

[vitesse]

Totally agree, don't care if it has legs or not as long as it opens at 88 degs I'd be happy. What troubles me is that even though I value your recommendation of Summit Garage, we have no real idea of how many they have, what happens when they run out? How do we identify 88 deg thermostats compared to 82 deg ones? With the low temperatures we get in Sweden an 82 deg thermostat is relatively useless without even considering the time/work involved.

Regards

[biffa75]

If the thermostat I have fitted (supplied) by summit garage works correctly and opens at 88°c, then they are to my knowledge and personal experience at that point a source of good kv6 thermostats. ( I will find out tomorrow all being well if the thermostat works correctly).

I was told by summit that they order directly from x-part. When the part arrived, it came with the saic roewe and mg branding stickers on the outer packaging indicating that it is authorised as a genuine or as near as genuine as possible and should meet the required quality standards set by mg rover. The best thing I could.suggest at this current stage if the thermostat I have actually works correctly, would be to speak to summit garage about any concerns you have.

I have been told x-part are currently looking into the current issues at manufacturer level in regards to the thermostats opening too early.

[biffa75]

If there stock runs out, I'm sure they could order a batch or however many from x-part. X-part approach manufacturers with all the technical information and then carry quality control over the product to make sure it works as designed and intended.

So if they do run out it shouldn't be an issue. (As said they are currently looking into an issue possibly at manufacturer level).

Other than actually cracking the new thermostat open when it arrives (rendering the unit useless afterwards) and testing the thermostat that way with hot water etc, there's no real way of knowing for absolute certain until it's fitted into the car.

I have tried using hot water and pouring it into the thermostat with 3 of the four ports blocked off and watching for the springs inside moving indicating movement but it isn't easy.

[vitesse]

Originally Posted by biffa75

If there stock runs out, I'm sure they could order a batch or however many from x-part. X-part approach manufacturers with all the technical information and then carry quality control over the product to make sure it works as designed and intended.

Just like they did with the genuine upper arms? Thanks but I'll pass and use re-use my old one should I need it.

Regards

[biffa75]

Best of luck I went to change my o ring on my original stat.. unfortunately the base of the stat broke where.it goes into the block.. so had no choice.

Im doing what I can to hopefully get something done about the thermostat issues as I won't be buying a Kaiser kit (as good as it may be).. it's an expensive upgrade I won't be forced into buying.. the orginal plastic design should be sorted.

In regards to the Indian upper arms.. I did so some reading about them.

Who was selling the arms? Did x-part actually confirm they were selling the arms to parts specialists?

Regards

[trikey]

X part had hundreds of the Indian arms in stock at the time they were found to be defective.