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Old 5th May 2021, 23:40   #1
Shuriken_57
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Default Kv6 new thermostat leaks?

Good morning, gentlemen.
When I fixed my fuel leak, I also replaced my thermostat because it was cracked and leaking.
I did install the new thermostat from dmgrs.
I followed rave procedure for coolant purge.

Yesterday morning , I saw a spot of coolant on the ground.
I checked the engine compartment and to my surprise, there was coolant under the thermostat.
I wondered if I had incorrectly refit the new thermostat . So , I started the operation again.
When I finished the job, I drove with the vehicle, the thermostat works well. I checked the thermostat on the way home and there were no leaks.

Today, I didn't use the vehicle, I inspected the engine compartment this morning and no trace of coolant.
But tonight, I wanted to take the vehicle out and there was coolant on the ground and under the thermostat.
How could the thermostat leak when I did not use the vehicle? This morning everything was clean, I don't understand .
Do you have an idea?
Thank you. ( I specify that I used the keyhole method)

Last edited by Shuriken_57; 5th May 2021 at 23:47..
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Old 6th May 2021, 09:02   #2
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Hello there, sorry to hear of the bother you're having!
This is usually down to a bit of crud on the O Ring sealing surface in the cylinder block - it can be very hard to clean up / see from all angles, and all it takes is a bit of detritus or pitting and you'll find you get a very annoying intermittent leak.

I'd inspect the mounting hole closely with a mirror to help you see all around it - if you have pitting it can be resolved by carefully refinishing the metal and then using a slightly larger O Ring (which we will of course supply free of charge).

Keep us posted with how you get on - we don't always see posts on here, but you can email us at sales@dmgrs.co.uk if I can help anymore.
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Old 6th May 2021, 11:25   #3
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Quote:
Originally Posted by DMGRS View Post
Hello there, sorry to hear of the bother you're having!
This is usually down to a bit of crud on the O Ring sealing surface in the cylinder block - it can be very hard to clean up / see from all angles, and all it takes is a bit of detritus or pitting and you'll find you get a very annoying intermittent leak.

I'd inspect the mounting hole closely with a mirror to help you see all around it - if you have pitting it can be resolved by carefully refinishing the metal and then using a slightly larger O Ring (which we will of course supply free of charge).

Keep us posted with how you get on - we don't always see posts on here, but you can email us at sales@dmgrs.co.uk if I can help anymore.
Thanks you. I've do the job twice but it leaking again.
Is it a O rings's problem?
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Old 6th May 2021, 14:00   #4
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By the way, the coolant temperature hardly reaches 80 and 85 in city. Is this an original mg rover thermostat? with the old thermostat, the temperature was around 90. The sensor is new.
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Old 6th May 2021, 17:00   #5
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Hello Brahim,

Sorry if I'm repeating questions that I've already asked you but ...
  • Did you renew all four 'O' rings?
  • After assembly did you remember to move the serrated clips on the straight pipe fully outwards?

Don't attempt to fit a larger 'O' ring to the thermostat housing. You will break it (I tried this as part of my thorough investigation of the cause of the leaks).

80 - 85 degrees is much too cool. Either the thermostat is faulty or it's not rated at 88 degrees. A genuine MG Rover thermostat is your best bet.

Simon
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Old 7th May 2021, 00:07   #6
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Quote:
Originally Posted by SD1too View Post
Hello Brahim,

Sorry if I'm repeating questions that I've already asked you but ...
  • Did you renew all four 'O' rings?
  • After assembly did you remember to move the serrated clips on the straight pipe fully outwards?

Don't attempt to fit a larger 'O' ring to the thermostat housing. You will break it (I tried this as part of my thorough investigation of the cause of the leaks).

80 - 85 degrees is much too cool. Either the thermostat is faulty or it's not rated at 88 degrees. A genuine MG Rover thermostat is your best bet.

Simon
Hello Simon, yes i used the new o rings and i moved the serrated clips on the straight pipe fully.
Where can i find an original thermostat ? It is bad to drive with this thermostat ?
Thanks you.
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Old 7th May 2021, 01:19   #7
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Hi shuriken,

I also fitted a new thermostat in November last year (also from dmgrs).
I also found my thermostat to be operating around 80-82c when driving and in stop start traffic to be around 85c.

It should be the 90c area.

Mine has been like this now for over 2,000 miles. I personally see it as a problem, but it can wait a little while before I spend that amount of money in the hope the part works as intended. To my knowledge it may just use slightly more fuel due to the cooler running temperature.(I'm also probably kidding myself here, but if it's running cooler, it's going to take a lot more for it to overheat).

As towards the leak, you say you have checked the serrated clips are pushed as far to the ends of that straight pipe as possible. Other than ensuring the mating faces on the block are perfectly clean. I could only assume it is a fault with the thermostat? Or a hose.

It could be a faulty thermostat, seeing how it opens too early, as does mine. It's possible there could be an hairline fracture in the plastic housing.
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Old 7th May 2021, 08:05   #8
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Quote:
Originally Posted by Shuriken_57 View Post
Where can i find an original thermostat ?
These people are X-Part agents and they post worldwide. I bought mine from them.

Use the official method of removing the plastic manifold chamber and one of the aluminium inlet manifolds for full access and a reliable result. Remove the fixing screw and carefully lever only under the bracket. Don't use the hose connections to remove or refit the parts. Lubricate and renew all 'O' rings, available separately, part no. CDU3858. Tighten the fixing screw to the specified torque. Move the serrated clips fully outwards and squeeze them tight. Follow the official refilling and bleeding procedure involving raising the expansion tank (you did do this before didn't you?).
Quote:
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It is bad to drive with this thermostat ?
Yes. Your fuel consumption will be high and the oil won't reach the optimum temperature which will hasten engine wear.

Simon
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Old 8th May 2021, 00:56   #9
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Have a look at Wes sale collection he as two of the stats for sale with the stabilising lugs on. also use a little red rubber grease when fitting the stat.

https://the75andztclub.co.uk/forum/s...d.php?t=312720
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Old 8th May 2021, 07:32   #10
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... he has two of the stats for sale with the stabilising lugs on ...


Definitely buy one of those Brahim. The three stabilising lugs are a very sensible modification, or "upgrade" as would be said here on the forum!

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