C43 Rethread oil filter housing on front cover
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2015 CLA45 AMG, 2012 E350
C43 Rethread oil filter housing on front cover
I was repairing an oil leak coming from the oil pressure port on the front timing cover, however when reinstalling the oil filter housing with the 46mm hollow nut, I cross threaded the threads in the front timing cover. I was using a 1 13/16" socket which was threading normally although had some wobble which I chalked to the shallowness of the bolt head/nut. I could lift the oil filter housing up still so knew something was wrong and noticed the threads in the timing cover have been cross threaded.
My options to fix are to helicoil/timesert or to retap the threads. I believe the threads that are left (only the first few are damaged) have enough material to be cleaned/retapped. I believe from my measurements of the body of the hollow nut, it could be a m35x2.5? The diameter I measured was about 35 and 2.5 mm between threads, but unsure where to get such a big tap without spending hundreds since itll only be used once. For such a big tap, is it possible to do it by hand or whats the best solution to repairing this? I plan on calling machine shops nearby.
My options to fix are to helicoil/timesert or to retap the threads. I believe the threads that are left (only the first few are damaged) have enough material to be cleaned/retapped. I believe from my measurements of the body of the hollow nut, it could be a m35x2.5? The diameter I measured was about 35 and 2.5 mm between threads, but unsure where to get such a big tap without spending hundreds since itll only be used once. For such a big tap, is it possible to do it by hand or whats the best solution to repairing this? I plan on calling machine shops nearby.
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From: Nor-Cal
2020 GLC300 -2014 Sl550 - 1997 SL600
You should be able to pick up a cheap tap for about $55 or so. You’ll be tapping into something soft, so should be OK with a cheaper tap.
https://www.ebay.com/itm/256488856628
https://www.ebay.com/sch/i.html?_nkw...&_sop=15&rt=nc
Unfortunately, it will probably come from China unless you can find a US supplier. So may take some time to get to you. If you want it quickly from a US based company then it will cost more.
Just make sure you get the right size!
Get a pitch gauge if you have to
https://www.haastooling.com
Good Luck
https://www.ebay.com/itm/256488856628
https://www.ebay.com/sch/i.html?_nkw...&_sop=15&rt=nc
Unfortunately, it will probably come from China unless you can find a US supplier. So may take some time to get to you. If you want it quickly from a US based company then it will cost more.
Just make sure you get the right size!
Get a pitch gauge if you have to
https://www.haastooling.com
Good Luck
Last edited by crconsulting; Nov 23, 2025 at 10:17 AM.
