In my quest to fix the 5V sensor rail I have removed the thermostat from the side of the engine. Mostly it was pretty painless, but getting the thermostat-waterpump pipe out of the back of the thermostat was challenging. "Just wiggle it off" says the handy youtube video. It did come off, but required excessive force and a couple of crowbars, mainly because of the poor access but it was tight! I wonder if the "O" rings on this steel? pipe have swollen. Can anyone tell me what these "O" rings should be? Can they be bought as a part from a main dealer, or will they only sell the whole pipe assembly?
Any tips for reassembly? Lubricating with soap might cause other issues. How about silicone?
Citroen relay 2.0 hdi 2017 thermostat-waterpump pipe "O" rings
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dpround
- Posts: 19
- Joined: 21 Apr 2023, 21:44
- x 1
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dpround
- Posts: 19
- Joined: 21 Apr 2023, 21:44
- x 1
Re: Citroen relay 2.0 hdi 2017 thermostat-waterpump pipe "O" rings
The "O" rings are available as a separate part, but they are £8 each, probably plus VAT!
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kk13171759588
- Posts: 12
- Joined: 22 Jan 2026, 03:08
- x 1
Re: Citroen relay 2.0 hdi 2017 thermostat-waterpump pipe "O" rings
1. O-ring procurement situation
For the 2017 Citroën Relay 2.0 HDI, the steel pipe O-ring from the thermostat to the water pump can be purchased separately. There is no need to replace the entire pipe assembly. Auto parts dealers and PSA Peugeot Citroën original parts channels can order separately. Just quote the model, displacement and sealing of the thermostatic water pump connecting pipe.
2. Lubrication and assembly skills
Do not use soap or regular silicone. Soap can contaminate the coolant. Ordinary silicone is not resistant to oil and high temperatures and will stick to death.
It is best to use original rubber grease, silicone grease compatible with coolant or a small amount of original antifreeze to smear the O-ring for lubrication to avoid damaging the rubber ring or affecting the cooling system.
When assembling, rotate and push evenly, do not pry hard, use rotation and lubrication to slowly put it in place to avoid deformation and cutting of the O-ring.
For the 2017 Citroën Relay 2.0 HDI, the steel pipe O-ring from the thermostat to the water pump can be purchased separately. There is no need to replace the entire pipe assembly. Auto parts dealers and PSA Peugeot Citroën original parts channels can order separately. Just quote the model, displacement and sealing of the thermostatic water pump connecting pipe.
2. Lubrication and assembly skills
Do not use soap or regular silicone. Soap can contaminate the coolant. Ordinary silicone is not resistant to oil and high temperatures and will stick to death.
It is best to use original rubber grease, silicone grease compatible with coolant or a small amount of original antifreeze to smear the O-ring for lubrication to avoid damaging the rubber ring or affecting the cooling system.
When assembling, rotate and push evenly, do not pry hard, use rotation and lubrication to slowly put it in place to avoid deformation and cutting of the O-ring.