Leaking FMOC
04-10-06, 03:52 PM
#3
The bungs on the 1st gen fmocs are weak. Often an owner will find a leak at the hose connection, tighten it down, and crack the bung. The cracks can be repaired by a competent aluminum welder. I have gotten bids from 15 to 55 bucks to do this. When the welding is done, the mating surface has to be absolutely flat for the crush washers to seal.
The bungs are also prone to cracking where they are welded to the tank, this can be fixed also.
Buy new crush washers and install them. I tighten down the hose finger tight, then give it another 1/4 turn with the wrench, start the engine up and look for leaks. Slowly tighten the connection until the leak stops. The engine will need to be at operating temps for full oil flow to check for leaks. The crush washers are basicaly a one time use only item, buy extras.
The bung issue is why I recommend using the 2nd gen fmoc when converting from the beehive, or replacing the oem one. They are cheap and plentiful compared the scarecer 1st gen ones.
Give the hoses a thorough inspection while your at it.
The bungs are also prone to cracking where they are welded to the tank, this can be fixed also.
Buy new crush washers and install them. I tighten down the hose finger tight, then give it another 1/4 turn with the wrench, start the engine up and look for leaks. Slowly tighten the connection until the leak stops. The engine will need to be at operating temps for full oil flow to check for leaks. The crush washers are basicaly a one time use only item, buy extras.
The bung issue is why I recommend using the 2nd gen fmoc when converting from the beehive, or replacing the oem one. They are cheap and plentiful compared the scarecer 1st gen ones.
Give the hoses a thorough inspection while your at it.
Last edited by trochoid; 04-10-06 at 03:55 PM.
06-29-06, 07:26 PM
#6
i believe my fmoc is now a victim of a leak at the hose fittings. these pictures were taken after about 10 minutes of 20mph driving around my block with the engine warmed up.
now for me to fix this, i can just follow trochoid's instructions? thank you first genners for all your help! thank you for helping me r&r my oil pan right on time for rotaryfest which was great! have a nice 4th of july weekend!
now for me to fix this, i can just follow trochoid's instructions? thank you first genners for all your help! thank you for helping me r&r my oil pan right on time for rotaryfest which was great! have a nice 4th of july weekend!
06-30-06, 05:42 AM
#7
Pick up extra crush washers when you get them. Copper ones, not aluminum. Before removing the lines, degrease and wipe down spotless, this will make future leaks easier to detect. What I have found works best is to hand tighten the fittings, then tighten with a wrench 1/3-1/2 of a turn more. Start the engine. If you find leaks, tighten gently, little by little, until the leak stops. Leave the engine running until it has reached operating temps, check for leaks again, if none are found, go for a short drive and redline it in 1st and 2nd, leave it running and recheck for leaks. let the engine cool down, then start it, warm it up and check again.
If you have a leak and tightening doesn't stop it, the bung may be cracked. Never overtighten the lines or reuse crush washers. Those are the 2 main reasons for leaks. If the bung is cracked, at the threads or the base, take the fmoc to a competent heliarc welder for repair.
If you have a leak and tightening doesn't stop it, the bung may be cracked. Never overtighten the lines or reuse crush washers. Those are the 2 main reasons for leaks. If the bung is cracked, at the threads or the base, take the fmoc to a competent heliarc welder for repair.
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06-30-06, 07:42 AM
#8
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Yea, I had to get the bungs welded on the front mount oil cooler inmy '79 a few years ago. Found a really good, experienced aluminum welder who did it for about $45. If you do this make sure they thread something into the bungs while welding so the threads don't get destroyed.
Rich
Rich
06-30-06, 09:21 AM
#9
i have never had crush washers go bad. not saying that they dont or cant, its just been in my experience of owning gsl-se's, that the bungs go due to vibration or bad oil cooler mounts and the cooler flops around on its lines and cracks the bungs. it is VERY easy to crack the bungs. be VERY careful!!!! i purchased an oil cooler last year to replace my original oil cooler and in the process or putting on new lines, i cracked the one of the bungs. i barely tightened it. or so i thought. i just put a new cooler on last week (thank you rx7doctor) and i followed my own advice and install procedeure and everything is beautiful. pull your cooler, clean it thoroughly at the bungs an look for hairline cracks. if its your crush washers giving up the ghosts, you are very lucky and need to take extreme care in your reinstall.
the job takes less than two hours from start to finish to remove and reinstall another oil cooler. add a half an hour for replacing the crush washers and cleaning. if you need detailed pics, let me know, i have them.
the job takes less than two hours from start to finish to remove and reinstall another oil cooler. add a half an hour for replacing the crush washers and cleaning. if you need detailed pics, let me know, i have them.
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