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13th September 2019, 09:49 | #1 |
Posted a thing or two
MGZT Join Date: Jul 2015
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KV6 overheating.Coolant cap.
My MGZTKV6 2.5 has run very hot of late and after investigation and testing showed no problems with the engine we have found the problem to be the coolant tank cap. Seemed unlikely so unlikely it wasn't considered initially and was discovered by process of elimination. A cap has been fitted supplied by Xpart and the temperatures are now spot on. One to consider if anyone has an overheating/hot running KV6. Chris.S.
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13th September 2019, 09:59 | #2 |
Doesn't do things by halves
Rover 75 2.5 Connoisseur Auto (1999) Dealer launch model. Join Date: Mar 2007
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Thanks for posting this Chris. It's always useful to remind members of this (as well as correct operation of the cooling fan) before the subject of head gasket failure rears its ugly head.
Sometimes however, it's just the two 'O' ring seals mounted on the expansion tank cap which flatten. They're not available separately from X-Part but something suitable can be obtained cheaply. Simon
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13th September 2019, 10:34 | #3 | |
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Rover 75 Saloon Join Date: Apr 2019
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Quote:
I fitted a brand new LR cap and the rings went flat straight away (these were standard rings, not Jack's Viton rings). Over-tightening the cap can almost certainly flatten the rings but I'd made sure not turn it past the first 'bite point' - and they still got flattened. The owners manual page 145 says this: Ensure the cap is tightened fully after top-up is completed. It doesn't say what fully tight is and it doesn't mention over-tightening. So it's difficult to know how much to tighten the cap on this car. Every other car I've had you just screwed the cap on until it wouldn't turn any further (i.e. it came up against the stops). The 75's cap seems to keep turning for much longer before anything mechanical stops it. Why? |
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13th September 2019, 10:49 | #4 |
This is my second home
rover 75 1.8 vvc club se wedgwood blue Join Date: Aug 2009
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Because it's spinning/tightening against the top washer, compressing it too far. I always apply vaseline to the rings and tighten just enough, and I have a 1.8
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13th September 2019, 10:53 | #5 |
I really should get out more.......
Rover 75 connoisseur se v6 auto Join Date: May 2014
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In my 1.8t i swop out the cap every 12 months -
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She came off the Longbridge Line on 20-05-2003 The Silver Machine was the 13th of 160 Rover 75's to come off the production line that day and is the 100th of 527 Starlight Silver Rover 75 2.5 V6 Connoisseur SE Auto saloons listed in the build records produced world wide. |
13th September 2019, 11:10 | #6 |
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Rover 75 Saloon Join Date: Apr 2019
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13th September 2019, 11:30 | #7 |
This is my second home
rover 75 1.8 vvc club se wedgwood blue Join Date: Aug 2009
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13th September 2019, 16:27 | #8 | |
Doesn't do things by halves
Rover 75 2.5 Connoisseur Auto (1999) Dealer launch model. Join Date: Mar 2007
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Quote:
Also, when the car is moving, is the temperature now stable within about +3˚? Simon
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13th September 2019, 16:39 | #9 | |
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Quote:
The phone call came in regard to this car couple of days ago, and given the fact it had expelled all of it's coolant over the engine bay, I surmised that the cap was defective, in all probability. The suggestion was to force the fan outputs with T4 ( all three working satisfactorily ) vacuum fill the car with coolant, and fit another cap, which was carried out according to the official MGR technique, and lo and behold all is good again So Chris could have saved a couple of hours labour by not buying a "genuine" cap from a source I'm not going to name At least he had the presence of mind not to refill the coolant (5 litres) lost until the engine had cooled Brian |
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13th September 2019, 17:45 | #10 |
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I accept Brians stricture regarding the genuine article but in my defence how do you know what is the genuine article? Even cost cant make that a certainty. I am however happy at this moment to accept I must tighten the cap until it stops and try harder to establish genuine articles. With this in view we must remember our cars have been out of production for 15 years with the a diminishing "official" support organisation and the growth of replacement parts of "apparent" similar quality. Its a lottery and in this instance I will hope I have a better chance of winning with the Xpart cap, note better chance not certainty! Thanks to all and hope not to reurn to this subject. Chris S.
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