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Old 8th October 2010, 19:45   #21
kennylenny
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Hi Guys do you think I've a stat problem and is there a goo way to check?I have been sat in traffic and the temperature gauge starts to rise - hits 12 o'clock - engine overheat warning comes on - I pull away and the temperature gauge returns to the usual 9 o'clock. I finally get home - open the bonnet to make sure I can't see anything untoward with the engine running, waiting for the temperature to go up again and.....nothing. The fan kicks in ok and the temp gauge stays at 9 o'clock. This has happened a couple of times with me getting home and checking and it's never happened when I'm waiting for it to do so. I drive 75 miles - no problem. I drive 75 miles back - no problem. I then stop the engine , leave it 10 minutes, sit in a small jam and the gauge rises again! Drive home let the engine run whilst sat on the drive, waiting for it to rise again and.....nothing. The temp gauge is fine. I'd already had the head gasket and thermostat done 8000 miles ago so does it sound like it's the stat again?
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Ken

Whoops - should have said - 2.5l KV6
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Old 13th October 2010, 22:51   #22
scaevola
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capese 21,
You ask the legitimate question " Is the OEM plastic thermostat housing actually that bad?" Yes, it is.
I suggest that the plastic thermostat housing is an excellent example of 'just adequate' design.
Adequate for say, 100,000k km or 8 years in ambient temperatures of -20C to + 30C, but quite inadequate for ambients of +20C to + 45C in tropical or desert locations.

Out here in the Antipodes, we Rover 75 owners are forced by the lack of service to help each other. So I've chatted with several other R75 KV6 owners over time.
So far, there has been a 100% failure rate of thermostat housings reported.
Some owners have even had the replacement OEM part replaced.
A Singaporean and South African member report similary in this forum.

Plastics degrade exponentially with temperature.
So the life of Rover's caprolactam derived component may be just adequate in temperate climes, but inadequate in severe service.

The ambient underhood temperature would exceed the 82C coolant temperature by many degrees. This component works in a very hot environment.
That you have had no problems in 6 years or 100,000km is no real test.
My thermostat housing failed quickly at 130,000km and 6 years.
This seems to be a common Time to Failure out here.

The Time to Failure in Europe may be longer.
But the OEM part is still poorly designed, and made from the wrong material.
Replacing plastic with metal is the only sensible fix.
Mr Kaiser's metal thermostat housing is the best option for replacement, especially if you intend to keep your Rover 75 for many years.
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Old 14th October 2010, 09:05   #23
capese21
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Quote:
You ask the legitimate question " Is the OEM plastic thermostat housing actually that bad?" Yes, it is.
In your opinion and experience. But not in mine!

I see no reason to fit a metal version when the service life of the oem one is perfectly acceptable.

I have one car which did over 60k / 6 years on its original thermostat without a problem. It was changed when the cam belts were changed as was the water pump which to me are all part of the cambelt change on the V6.

I would not go to all the expence of a cambelt change and not include a new thermostat housing and water pump. Thermostats can fail regardles of what material the housing is made of.


If the "inferior plastic" one lasts another 6 years / 60k miles then I will change it again when the cambelts are changed. I see no reason to take it out before and fit a home made metal one.

I agree perhaps the higher temparatures in Africa or Australia may cause the plastic one to fail earlier
My engine though runs at the pretty much the same temp in the winter as it does on a hot summers day. I know as I have the Hans guage fitted.

What temp does your engine run at? mine is between 92 and 96 iirc.

Good luck with your metal version. I will not be fitting one.

Ed.

Last edited by capese21; 14th October 2010 at 09:07..
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Old 14th October 2010, 11:19   #24
Bernard LPG
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Quote:
Originally Posted by capese21 View Post
In your opinion and experience. But not in mine!

I see no reason to fit a metal version when the service life of the oem one is perfectly acceptable.

I have one car which did over 60k / 6 years on its original thermostat without a problem. It was changed when the cam belts were changed as was the water pump which to me are all part of the cambelt change on the V6.


Good luck with your metal version. I will not be fitting one.

Ed.
My plastic housing had failed at 18k miles. I reluctantly replaced it with the OEM part because at that time there was no choice.

As I had seen this same housing split on the Rover 825 with the KV6 engine, I made the decision to replace it with Kaiser's unit at the timed out cam belt change point. The plastic version has had 2 chances with me, that is sufficient.

I am no longer paranoid about it.

We all have different experiences.
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Old 18th October 2010, 21:30   #25
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Just an update on my installation of the metal thermostat...

I noticed the coolant was starting to drop again. Not a lot but a cupful a week.

I took the old girl into Terry's at Stourbridge and he replaced the old OEM hose clips with Jubilee Clips. No more problems and now done quite a few thousand mikes since.

If anyone is contemplating changing the thermostat (Plastic or Metal) Change the hose clips at the same time.

Everyone is entitled to their opinion but I drive with a lot more peace of mind with Keiser's thermostat installed.

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Old 19th October 2010, 00:36   #26
Jules
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My ZT-T 190 Plastic Stat is leaking at just 10k miles from new.
Guess what it's getting for a Christmas present.
Now where's Kaiser when you need him !!
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2. Cooling fan..All speeds functioning
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Old 25th October 2010, 22:48   #27
scaevola
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capese 21,
Thanks for reporting that your plastic thermostat housing has lasted for 60K miles.
The reports of failure of the same part after 10K and 18K miles indicate that you have been lucky.
However, hoping for good luck is not a good basis for having trust in the reliability of one's Rover.
Especially when nearest help is 200km away, and the Outback is 40C in the shade.

That there is and has been a problem with KV6 thermostat housings is indisputable.
That these failures follow a Poisson (binomial) distribution is probable.
That the mean Time to Failure is skewed to a lower value by higher operating temperatures is highly likely.
That metal will last longer than plastic at high temperature is self evident.

Therefore replacing the OEM part with Mr Kaiser's well-designed and well built part is the only rational response to the problem.
To call Kaiser's replacement part 'a home made metal one' is rather unfair.
Kaiser's part is well designed and well made.
I have one fitted. My car has not lost a drop of coolant in 6 months.

The small premium that buying his superior part incurs is well worth the renewed confidence it gives in the reliability of one's vehicle.
Installing Kaiser's part has allowed me to keep my Rover for years more.
For that reason alone, it is a bargain.
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Old 26th October 2010, 09:12   #28
capese21
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Quote:
Thanks for reporting that your plastic thermostat housing has lasted for 60K miles.
All I am saying is imho the plastic original is not that bad. I have not had a problem with it on my car.

Some have reported early failures but plenty (the majority?) of them have also lasted well in excess of 60k miles.


Ed.
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Old 13th November 2010, 06:56   #29
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As I have said in my OP above when Dr Dave got to my plastic thermostat it was in fact okay and this was at close to 100K miles...



The leak I had was from the small hose clip which was changed later. But to be honest I still feel more confident with Kaiser's metal version although I had to change the clips at a later date for jubilee type ones.

Even if some people refit a plastic one they should replace the hose clips with Jubilee ones.

But if anyone is going to go to the effort of replacing the thermostat then to be honest the metal one wins hands down. Fit and forget.

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Last edited by Mr Edd; 13th November 2010 at 06:58..
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Old 27th January 2011, 09:02   #30
David3807
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Have had three thermostats fail between my two 75s. One actual stat failure and two with split casing.

The stat one lasted about 5 years and 55k. the replacement lasted two years and 14k miles before it split.

The last split casing one was original fit on the car and went at about 65 k miles and 8 years.

As there would appear to be some truth in the theory that stats and plastic housing fitted originally were of better quality that later replacements I went for a metal replacement.

No problems in fitting and no leaks yet.

The only downside is that the warm up time has about doubled which in the cold weather over the past month or so has increased fuel consumption a fair bit.

As suppled by Kaiser the stat is an 80c one. I was wondering if say an 85c or 88c would be a better bet in the uk. Any one any thoughts ?? Kaiser ??

And would an MGR Stat (which I believe is an 88c one) be a suitable replacement.
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