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Old 4th May 2019, 19:24   #1
Rsnail
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Default Coolant loss

Hello guys, for about 1 and a half - 2 months the car's been loosing coolant, about 0.5 to 1l per week... now my question is, which could be the possible most suspect culprits? I am thinking that it could be the thermostat housing, my thermostat has been stuck on open (thanks God haha) since I bought the car lol (almost 4 years ago), and I haven't bothered fixing it since having it stuck on open would always circulate the water through the radiator and the worst and only thing it can happen is, when driving on the highway, you'll have the water a little colder than normal 80-90°C which isn't really an issue. But the interesting thing is, why would the thermostat housig give up now only, aloooot later than the thermostat itself? Maybe it's not that at all, any ideas?
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Old 4th May 2019, 19:53   #2
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My car was losing a small drop of coolant every week, thermostat packed up then temp sensor, constantly checking levels for nearly 2 years. Had cambelt, tensioner and water pump changed now absolutely fine. Obviously a very small leak from water pump no sign of coolant loss!
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Old 4th May 2019, 20:15   #3
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Quote:
Originally Posted by Rsnail View Post
- - - having it stuck on open would always circulate the water through the radiator - - you'll have the water a little colder than normal 80-90°C which isn't really an issue.
So how colder does it run? Remember there's issues from running too cool as well too warm. You need to be running well above 80C to avoid over-fuelling and engine wear. Is the temperature gauge reaching the 'normal' position?

Have you checked the actual running temperature using the trip screen diagnostic?

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Old 4th May 2019, 20:28   #4
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When driving normal, temp gauge is in the middle position. Temp gauge is at about 25% level when driving fast because the air flowing fas in the radiator, so about 80-90°C. Can you please tell me how to check the temp using the trip screen diagnostic? Thanks

And Brunty, I can't really understand what you mean, was your problem the thermostat and temp sensor and now you changed them and it's all right or was it the water pump?
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Last edited by Rsnail; 4th May 2019 at 20:32..
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Old 4th May 2019, 20:37   #5
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Describing the temperature gauge needle position by using the clock face will make things clear.

Normal is at 9 0'clock. I guess you mean 6 o'clock in your post.

Much too cool.---
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Old 4th May 2019, 20:50   #6
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Nope, it's at 7 and a half - 8 am position. But I am trying to figure out here what are the causes of the leakage guys haha, as said, I drove the car with the thermostat stuck on open for almost 4 years and the fuel avarage is at 8.5 l/100km so that's nit a problem, and I don't think the engine got worn by this because I raaaarely drive at high speeds so the water almost never gets to stay cold. And anyways, if the cause is other than the thermostat housing, I'll have the thermostat and the housing replaced soon with a metal one anyway.

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Old 5th May 2019, 06:36   #7
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Also, how can I flush the system before installing the new thermostat when buying a new one? Right now my thermostat is stuck on open so I guess it will be easier to flush the system now in this condition.
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Old 5th May 2019, 06:48   #8
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Changed thermostat and temperature sensor, now running 95-96 degrees. Did not alter the coolant loss. New water pump cured the problem.
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Old 5th May 2019, 07:56   #9
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These would be my top 5 on a KV6

Thermostat & pipework
Bottom pipes across subframe
Oil cooler
Water pump
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Old 5th May 2019, 08:54   #10
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Quote:
Originally Posted by Rsnail View Post
When driving normal, temp gauge is in the middle position. Temp gauge is at about 25% level when driving fast because the air flowing fas in the radiator, so about 80-90°C. Can you please tell me how to check the temp using the trip screen diagnostic? Thanks

And Brunty, I can't really understand what you mean, was your problem the thermostat and temp sensor and now you changed them and it's all right or was it the water pump?
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There you go -instructions to get the onboard diagnostics working - pretty impressive for a 20 year old design. You need to set up the 19-7 setting -this will display your real time running temperature as you are driving along.

https://www.the75andztclub.co.uk/for...38&postcount=1
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