KV6 noisy Purge Valve

Bob Walker · 11th April 2021, 15:27

Dear All
I have finally sorted out the thermostat leak but when I started the car the purge valve rattles a great deal! It has been doing this for quite a while. I have a new one and it looks straight forward to replace but how do you remove the plastic pipe? It has some kind of plastic clip that you seem to press on both sides to release, is this correct? I am a bit wary as every thing I touch on the engine made of plastic seems very brittle! I only looked at the breather pipes and they fell apart!
I look forward to your advice and best wishes,
Bob

T-Cut · 11th April 2021, 20:13

Hello Bob. The purge valve operates under the control of the engine's ECU, so if it's running, then the ECU has switched it on for a reason. 'Offically', the purge system only operates when the engine control is in 'closed loop' mode, which requires it to be fully warmed up. However, It's also clear from my own experience over the years and from forum reports that it will also be tripped on if the carbon canister is saturated when the cold engine's started. You then get the usual clatter (or Slack Tappet Syndrome 'STS' as I call it) on starting up the engine whatever control loop is operating. This circumstance might occur after a long period of standing (eg Covid lockdowns). So, I honestly doubt that replacing the purge valve will change anything. I'd suggest taking the car for a decent run to enable the absorbed fuel vapours to be purged from the canister.
Hope this helps.

TC

Bob Walker · 12th April 2021, 11:28

Dear T-C
Thank you for this, it is really appreciated. My thermostat started leaking in January, just as I was about to take an 84 for her Covid jab at Tennants in North Yorkshire. I parked up the car and took her in a TF, it was quite an experience for her! I finally got around to replacing the thermostat last week, I still have the scars to prove it (!), when I started it up for the first time in 13 weeks it was making a hell of a racket! It seems to have settled down now and I have no more coolant loss. The key hole method for replacing the thermostat is a really good guide, but you need arms that are really thin to get to the 10mm bolt holding the thing down, it took me ages to sort it out!! I had forgotten just how nice a car it is!!
Thanks again for your advice,
Bob

11th April 2021, 15:27	#1
Bob Walker Loves to post MGZT Join Date: Aug 2019 Location: Richmond Posts: 255 Thanks: 26 Thanked 80 Times in 45 Posts	KV6 noisy Purge Valve Dear All I have finally sorted out the thermostat leak but when I started the car the purge valve rattles a great deal! It has been doing this for quite a while. I have a new one and it looks straight forward to replace but how do you remove the plastic pipe? It has some kind of plastic clip that you seem to press on both sides to release, is this correct? I am a bit wary as every thing I touch on the engine made of plastic seems very brittle! I only looked at the breather pipes and they fell apart! I look forward to your advice and best wishes, Bob

11th April 2021, 20:13	#2
T-Cut This is my second home Rover75 and Mreg Corsa. Join Date: Nov 2006 Location: Sumweer onat mote o'dust (Sagin) Posts: 21,753 Thanks: 341 Thanked 3,660 Times in 2,924 Posts	Hello Bob. The purge valve operates under the control of the engine's ECU, so if it's running, then the ECU has switched it on for a reason. 'Offically', the purge system only operates when the engine control is in 'closed loop' mode, which requires it to be fully warmed up. However, It's also clear from my own experience over the years and from forum reports that it will also be tripped on if the carbon canister is saturated when the cold engine's started. You then get the usual clatter (or Slack Tappet Syndrome 'STS' as I call it) on starting up the engine whatever control loop is operating. This circumstance might occur after a long period of standing (eg Covid lockdowns). So, I honestly doubt that replacing the purge valve will change anything. I'd suggest taking the car for a decent run to enable the absorbed fuel vapours to be purged from the canister. Hope this helps. TC

12th April 2021, 11:28	#3
Bob Walker Loves to post MGZT Join Date: Aug 2019 Location: Richmond Posts: 255 Thanks: 26 Thanked 80 Times in 45 Posts	Dear T-C Thank you for this, it is really appreciated. My thermostat started leaking in January, just as I was about to take an 84 for her Covid jab at Tennants in North Yorkshire. I parked up the car and took her in a TF, it was quite an experience for her! I finally got around to replacing the thermostat last week, I still have the scars to prove it (!), when I started it up for the first time in 13 weeks it was making a hell of a racket! It seems to have settled down now and I have no more coolant loss. The key hole method for replacing the thermostat is a really good guide, but you need arms that are really thin to get to the 10mm bolt holding the thing down, it took me ages to sort it out!! I had forgotten just how nice a car it is!! Thanks again for your advice, Bob