Oil Leak

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LSV8FAN

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The 2005 Lincoln LS V8 had a one time (so far) oil leak. Took the car for like a 30 mile round trip and parked it in the garage. Two days later, when my wife took it out to go shopping, I noticed an oil puddle on the floor and after she came back from shopping and parked the car, there were no additional leaks. Next day, upon inspection to determine where the leak came from I saw that the driver's side valve cover had a leak around the oil fill tube; the oil fill tube had drops of oil practically all the way up to the cap. I checked and found the oil fill tube had a very small gap between it and the valve cover, indicating that the gasket was no longer providing a good seal; when I tried to wrap a thin kite string around it, the string only fit about 25% of the diameter of the fill tube. Per design, to replace the gasket one needs to remove the valve cover to be able to deflect the snaps to remove the oil fill tube. Instead, I cleaned the area around the fill tube and used J-B weld 2-part epoxy with metal to seal the gap between the valve cover and fill tube.

Since it was time for the oil change (I do it once a year in October since we put an average of 1,600 miles/year), upon removal of the oil filter there was more than I typically saw oil pouring out of the filter adapter and, after pouring the oil out of the filter and setting it aside standing up, I didn't see additional oil accumulating at the bottom of the filter. This leads me to believe that probably the check valve inside the filter was stuck and didn't allow oil to properly circulate within the filter, instead it just by passed it.

The car only has 88,600 miles and has been working fine, so I don't understand whether there was some significant pressure build up under the valve cover that caused oil to leak out or it is normal for oil to leak out when the seal between the fill tube and valve cover fails. If it was pressure, that should have been relieved through the hose that connects from the valve cover to the air intake.

I'll continue observing to see whether this was a one time event related possibly to a filter failure, or if there is something else that has failed. Any comments and feedback you have are appreciated.
 
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The O-ring leak on the filler neck to valve cover is common. Live with it because the fix isn't as easy as it looks.

The last time I did my valve covers I installed a slightly larger O-ring on the filler neck.

Guess what? After some time the filler neck tube started leaking again.

Filler neck tube leak is normal

You also said something about a leak at the oil filter. That is a different issue.
 
My 06 was seeping oil in the exact same place i noticed i could grab the filler neck and move it up and down slightly and oil was coming from that small gap where the filler neck sets on the valve cover. I do not think mine was caused by pressure build up what i did notice is that the drivers side short valve cover breather hose that clips to air intake tube port was not sealing all the way so theyre was nothing pulling vaccum from that valve cover it was just venting out that hole under the hood. After replacing that hose and pushing a tiny amount of gasket maker into that gap under the filler neck i solved the filler neck oil seepage problem.
If its not a leaky hose and you actually have pressure build up i would take my valve covers off and clean those copper looking breather elements thats inside the valve covers to make sure vaccum is flowing freely through them and i would take all my valve cover breather tubes and clean those out to make sure you are getting proper air flow through them.
As far as the oil filter always use OEM Motorcraft filters so it will have the anti drainback valve to help protect your engine. Hope this helps.
 
Buckie said:
My 06 was seeping oil in the exact same place i noticed i could grab the filler neck and move it up and down slightly and oil was coming from that small gap where the filler neck sets on the valve cover. I do not think mine was caused by pressure build up what i did notice is that the drivers side short valve cover breather hose that clips to air intake tube port was not sealing all the way so theyre was nothing pulling vaccum from that valve cover it was just venting out that hole under the hood. After replacing that hose and pushing a tiny amount of gasket maker into that gap under the filler neck i solved the filler neck oil seepage problem.
If its not a leaky hose and you actually have pressure build up i would take my valve covers off and clean those copper looking breather elements thats inside the valve covers to make sure vaccum is flowing freely through them and i would take all my valve cover breather tubes and clean those out to make sure you are getting proper air flow through them.
As far as the oil filter always use OEM Motorcraft filters so it will have the anti drainback valve to help protect your engine. Hope this helps.
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Thanks for the feedback. I always use Motorcraft 5W20 Synthetic Blend oil and Motorcraft oil filter (# 2021). The short crankcase vent tube and all other hoses look good.

Sealing the fill tube to the valve cover didn't solve the oil drip problem, although it fixed the oil seeping around the fill tube. The oil drops were at the bottom where the transmission is joined to the engine, however it doesn't look like it is a main rear seal because the leak looks to originate much higher up, like it may be the passenger side valve cover. There is no room to see or even stick my hand in there to feel if there is oil or not, but I could see under the car that the oil was coming from higher up the engine block.

After reading on the internet about the different oil additives, I resorted to add an 8oz bottle of ATP's AT-205 Re-Seal Stop Leak and it looks good so far. I added the stop leak and run the engine until it reached operating temperature; the car was driven once since then for about 5 miles and there looks to be no sign of oil dripping. I'll continue monitoring and report back whether the AT-205 sopped the leaks or not. I read that people use the AT-205 to coat rubber and other type of sealing components and it rejuvenates them; something to think about using on bushings that harden up with age.
 
LSV8FAN said:
Thanks for the feedback. I always use Motorcraft 5W20 Synthetic Blend oil and Motorcraft oil filter (# 2021). The short crankcase vent tube and all other hoses look good.

Sealing the fill tube to the valve cover didn't solve the oil drip problem, although it fixed the oil seeping around the fill tube. The oil drops were at the bottom where the transmission is joined to the engine, however it doesn't look like it is a main rear seal because the leak looks to originate much higher up, like it may be the passenger side valve cover. There is no room to see or even stick my hand in there to feel if there is oil or not, but I could see under the car that the oil was coming from higher up the engine block.

After reading on the internet about the different oil additives, I resorted to add an 8oz bottle of ATP's AT-205 Re-Seal Stop Leak and it looks good so far. I added the stop leak and run the engine until it reached operating temperature; the car was driven once since then for about 5 miles and there looks to be no sign of oil dripping. I'll continue monitoring and report back whether the AT-205 sopped the leaks or not. I read that people use the AT-205 to coat rubber and other type of sealing components and it rejuvenates them; something to think about using on bushings that harden up with age.
Click to expand...
Your welcome. I wished i woulda known i could use AT-205 on my bushings because i took bearing grease and hand coated every bushing i could reach when i first bought my LS. It stopped all the squeaks but it was really messy. AT-205 is supposed to be pretty good stuff so hopefully it fixes you're problem. Those valve cover gaskets are known to leak especially on the inside where the spark plugs screw in. I had to replace my gaskets because i could see oil starting to come out from around several coilpacks. One more thing, this is probly not related to you're problem but i read on here someone said the motor mounts are oil filled, not sure with what kinda oil but i just thought id mention it incase you have a leak in the future and can't find the source.
 
I want to give an update regarding the oil leak. After I added the AT-205 Re-Seal Stop Leak, to date, there are no more leaks. I couldn't find details about its use, whether it needs to be added with every oil change or to be added just once and that's it, other than there was one posting where the person added it once and after 3+ years there were still no leaks. If anyone wants to use it for other than just an engine, trans, power steering or other oil additive, I suggest reading postings on the internet because in certain cases it could cause damage, like if applied/sprayed on electrical wiring.
 
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