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Old 13th February 2024, 23:30   #61
Matt_75
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Now you mention it, the new thermostat was marked 82C on the casing. I didn't think much of it at the time, but believe the original factory thermostat was an 88C one. The new one is an MG Rover branded one made in the UK, I don't know why the opening temperature has been reduced? The one I removed was also marked 82C which might explain why the engine ran cooler than my own KV6 which I believe to be still fitted with the original one.

I think for now, I'll stop fixating on the temperature and concentrate on getting the tests/inspections done. This probably won't be for a couple of weeks though as I need to focus my efforts on getting the Dolomite ready for some events on March.
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Old 14th February 2024, 08:13   #62
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Default 88C thermostats

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Now you mention it, the new thermostat was marked 82C on the casing ... The one I removed was also marked 82C ...
Don't worry about that Matt. All the housings are marked 82C (my factory fitted and replacement are) but if you test the thermostat in a pan of heated water with a thermometer you'll find that it is, in fact, rated at 88C.

You've raised some doubt in my mind concerning reports on this forum that new thermostats are now all 82C. It seems likely that folk are relying on this housing marking which has never been correct.

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Old 14th February 2024, 18:28   #63
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I keep looking at philt4 "s comments in a post dated 7/7/2017 where he had confirmation of the stat insert temps for PEM101050 from xpart by email. The stat insert is Part PEL100370. STO temp = 80 to 84 c so therefore stamped middle tolerance of 82 c . with a fully open temp of 96 c degrees. Rather difficult to estimate the opening start in a bowl of heated water ,as the eye cannot judge i would imagine , the first small increments. So quite possible the new stat could be opening a lot earlier than the 88 c expected. As phil commented at the time,you would not know what changes have been made once china took the reigns over. I dont think that the latest ones have the older stat specs,but could be wrong of course. This earlier opening temperature would fit in with the readings shown on the IPK as it does on my hans gauge which i see every day on my 82 c stat. Either way mat it does not present a major issue and proves at least that the engine is being cooled adequately with a good coolant flow. The big test will be the compression test results , which hopefully will reveal all. In the meantime , good luck with DOLLY ....
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Old 15th February 2024, 08:54   #64
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I keep looking at philt4 "s comments in a post dated 7/7/2017 ...
Thanks very much for this Stefan. It took perseverance to find it because the July posting was in 2021 not 2017! Here's a link to it.
Sorry but either this information from X-Part is incorrect or a typing mistake has been made in the post.
My car was built four years after the alleged reduction to 82˚C in 1995 and my original thermostat when tested began to open at 88˚C.
Furthermore, owing to accidental housing breakage during the testing of larger 'O' rings, I replaced it with a new one from an X-Part agent in 2017, over twenty years after the alleged change. There is no doubt that this also opens at 88˚C.

Unless the thermostat operation fails mechanically (which is very rare on the petrol engines) it's beneficial to keep the original factory fitment. 88˚C thermostats have been used satisfactorily by manufacturers for the UK market for decades so I see no technical justification for change.
When coolant loss occurs in the KV6, it is not due to a thermostat housing fault. All that is required are new 'O' rings and setting the serrated clips outwards on the straight pipe.
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Rather difficult to estimate the opening start in a bowl of heated water ,as the eye cannot judge i would imagine , the first small increments.
I've tested thermostats in this way many times over the years Stefan and the initial opening can be seen clearly, but absolute precision is not necessary. There's an easily identifiable difference between 82˚C and 88˚C as when heating the water slowly that rise takes quite some time.
The difficulty with the KV6 'stat is that it cannot be removed from the housing without destruction making observation much more difficult. I tested one I had removed from the broken housing and it began opening around 88˚C.

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Old 15th February 2024, 13:42   #65
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Hi simon. Sorry for the post date typo for the philt4 post... I assume it was a lengthy process ,knowing how many posts philt4 amassed over the years. !! The bottom line is that whatever temperature stat is in the thermostat, it is cooling the engine and not really that much of an issue at present. The reason i picked up on this point was that his warming up figures ,related to the stat, seemed exactly to follow my own stat figures ,having an 82 c stat fitted.I always find a very slow temp rise around the 78/80 point on warm up. This is what was pointed out and puzzled mat , and mine does the same. It did cross my mind that because of the fact that the roewe 750 was never for intended sale in europe, that the newer legged versions , were addressed to the warmer temps of the Asian market. Who knows what make or temps are now fitted.... you get what you get , and it is what it is. If its opening at the correct temperatures lucky mat !! We must still bear in mind that there must have been issues with the thermostats in china, to even go to the trouble of putting legs on to the stats. .. so new drawings for the stats have been drawn up for remanufacture. O rings problem never fully addressed by the chinese ... but hey ho !! Apologies again for the date typo simon ...

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Old 16th February 2024, 23:48   #66
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Hi Simon. I have fitted an in line thermostat. I asked for a 88 deg thermostat, and was sent a 82 deg one instead. And with obd in operation, it registers ........82 deg, when running. It occasionally goes up to 83/84 when getting a move on in summer.
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Old 17th February 2024, 08:05   #67
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And with obd in operation, it registers ........82 deg, when running. It occasionally goes up to 83/84 when getting a move on in summer.
Is this on your diesel or KV6 please Dave?

Simon
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Old 17th February 2024, 08:23   #68
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Sd1too keeps mentioning the v6 thermostat housings do not fail and its just the o rings, I can say from experience that they do leak on the seam and for a bit over an hours work so much easier to replace it all, over the years I have changed in excess of 100 v6 thermostat assembly's of which I'm sure some of the members who's cars they will remember

I did one for a member last week and the top part had totally split apart
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Old 17th February 2024, 08:34   #69
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PM Sent Matt
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