Coolant temp sensor o-ring leak
 

Hi,

On my 4.6is, coolant leaks from coolant temp sensor o-ring which is located in lower rad hose.
Although BMW doesn't carry individual part number for the o-ring, after much searching, found part # 13621743299 can be used as replacement.

Has anyone tried it with much success?

Thanks,
Simon

Hey,

I also have that o–ring seeping and was wondering if there was way to save a hose,but the o–ring you gave a number of is probably made of a different compound and may be not suitable for cooling system applications.
Give that you have to drain your coolant anyways,probably it would be a good idea to just replace a hose if the money side isn't an issue.

Mine was green when I replaced it. I got it from FCP and their part number was 091158010

I wrapped mine with a few wraps of Teflon tape for an emergency fix. I've found a 10 pack on Amazon for about $5 I will probably buy them and can send some around in an envelope once I do.

To replace without draining I made an artificial finger from some foam in a finger from a nitrile gloves and it held tight while I wrapped the sensor with Teflon. It's been working for a month but I do want to replace. I think its 3x8x14mm but I've not found that size in any stores.


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Thank you for input and part number guys.
I've replaced the hose, but new hose didn't come with temp sensor, hence I had to re-use old temp sensor.
It didn't leak in the old hose, but started leaking in new hose.

Having said that, coolant is already drained and I'll be going with 13621743299 for replacement.
Once everything is done, I'll report back.

Uxcell 8mm x 14mm x 3mm 10 Piece Brick Red Flexible Silicone O Ring Seal Washer https://www.amazon.com/dp/B01AXHQZQW..._9sgIAbYMJTCTT

Ten pack of the o-ring


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M3x8 Viton O-Ring, 75A Shore Durometer, Round, Black, 8 mm ID, 14 mm OD, 3 mm Width (Pack of 10) https://www.amazon.com/dp/B005RUSWCG..._NmhIAb1CQGP7W

Twice the price but prime eligible.

Send me private message if you'd like one I should have about five to spare once I get them into the cars where I can use them. I would change this o-ring on any 100,000 mile BMW at earliest convenience (whenever coolant drained)


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To be clear I ordered a ten pack and will have spares. Need one let me know for say $2 for 1 or $3 for 2 I'll drop in a little padded envelope.


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Thanks for the offer, but ended up buying part # 13621743299.
As far as material, I'm not sure, but iit was the same size and same green color o-ring. Leak is stopped but now it's leaking from transmission thermostat... :(

i replaced mine with another temperature sensor i pulled out of a junk car this winter and it worked out perfectly.

my friend who's an enthusiast advised me to completely change the lower hose and temp sensor.