E55 thermostat housing bolt size
Thread Starter
Junior Member
Joined: May 2021
Posts: 27
Likes: 1
03 E55 AMG
E55 thermostat housing bolt size
Installed a creative steel belt wrap kit and applied to much pressure on the thermostat housing bolt and stripped it out. FYI, don't use an electric ratchet it will strip the threads. Now I have a coolant leak. Will have to tap new threads and install a larger bolt. Hoping I can find a larger bolt locally. Does anyone know the factory bolt size? Hoping Fastenal store will be able to help me out.
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Joined: Jun 2020
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2006 CLS55 AMG, 2005 SLK 350 AMG
T'stat does not bolt to the water pump it bolts to the timing cover. I think the bolt is a 8mm diameter but I do not know the length. If you don't have calipers you can measure the diameter with a simiple rulling 8mm = 5/16in. You should be able to confirm the length when you take the bolt out. If it were me, I would get the old bolt out and try to clean up the threads to use the correct sized bolt. If that does not work, then use a heli-coil for the correct sized bolt. Good luck.
Thread Starter
Junior Member
Joined: May 2021
Posts: 27
Likes: 1
03 E55 AMG
Helicoil
Thanks for the responses. The threads are too damaged to clean up. Ordered a helicoil kit. Biggest pain is getting the radiator out of the way. Will tackle this the next weekend I am off.
