radiator coupler O ring installation

bmwM5power

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Joined
May 3, 2007
Location
Rochester NY
TDI
15 GSW TDI S 6MT 02 JETTA TDI GLS 5MT 15 GOLF TDI SE 6MT 15 GOLF TDI SEL DSG
whats the proper procedure to replace the upper and lower radiator coupler O ring? i replaced the leaking radiator and was gonna replace the O ring on those 2 couplers, please, advise
 

PakProtector

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Joined
Jan 5, 2014
Location
AnnArbor, MI
TDI
Mk.4's and the Cummins
IMO, grease them. Using something impervious to glycol; Krytox comes to mind...and same for any of these clip connections like the heater.

Douglas
 

bmwM5power

Veteran Member
Joined
May 3, 2007
Location
Rochester NY
TDI
15 GSW TDI S 6MT 02 JETTA TDI GLS 5MT 15 GOLF TDI SE 6MT 15 GOLF TDI SEL DSG
thank you for the answer, to clarify a little, the reason for asking is I read somewhere that I need to put the O ring on the male side of the radiator (the flange), I greased it up with silicone grease, but there is no way I can put the coupler on like that. Is it ok to put the new O ring into the groove on the female side ( the coupler) where the old O ring was and then press it in?
 

gforce1108

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Aug 2, 2006
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Newburgh, NY
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04 Jetta GLS BEW, 14 Audi A7 V6 TDI, 13 Porsche Cayenne V6 TDI
The oring goes inside the groove in the coupler - not on the radiator. I just replaced a mkiv radiator and now have a slight drip from that connection. Oring was cleaned and lubed. Unknown brand of radiator - came free with another of his cars and didn't have time to order/locate orings.
 

agent_jwa

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Feb 9, 2024
Location
WI
TDI
02 Golf
The o-ring goes into the groove, I use a tiny bit of super lube on the o-ring and on the radiator.

Part number N90765301 just got them from the dealer last night like 2.50 each
 

03TDICommuter

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Dec 8, 2016
Location
So. Cal
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01' NB, 5spd
I just did this on my beetle. You need to pick out the old orings from the coupler, lube and install the new ones. I use silicone o-ring grease sparingly as the lube.

BTW, for the thermostatic switch screwed into the radiator tank, did yours have a gasket?
 

agent_jwa

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Joined
Feb 9, 2024
Location
WI
TDI
02 Golf
Mine didn't but I just used some Teflon tape and it doesn't leak at all. I was surprised with all the other stuff having o rings
 

bmwM5power

Veteran Member
Joined
May 3, 2007
Location
Rochester NY
TDI
15 GSW TDI S 6MT 02 JETTA TDI GLS 5MT 15 GOLF TDI SE 6MT 15 GOLF TDI SEL DSG
I just did this on my beetle. You need to pick out the old orings from the coupler, lube and install the new ones. I use silicone o-ring grease sparingly as the lube.

BTW, for the thermostatic switch screwed into the radiator tank, did yours have a gasket?
it didnt, i put a lil of teflon tape, all good
 
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