173000 on a mountaineer 5.0. 4 months and 4000 miles and I only drained out 3.5 quarts out of 5.5 and now have a rear main oil seal leak. truck has had motorcraft 5-30 blend its whole life and I changed only to even up both cars. Should I drain it and go to a Pennzoil high mileage or go back to the motorcraft? but could the damage have already been done?
syn switch NOW LEAKS AND BURNS ????
- Thread starter MiKe3o
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Well nothing (except repair) is going to fix the leak if it is truly a rear main seal leak. Yes you can switch to a HM oil and it may slow it some. Yours does not sound to be terrible so I would go ahead and use the HM oil of your choice.
So you switched to synthetic and when it was time to change the synthetic oil out you THEN noticed you were 2 quarts low and it was leaking?
What synthetic did you switch to?
Nothing is likely to repair a RMS leak, even though some claim ATP-205 will fix a slower leak. If it's already on the chopping block with 173k , might as well try it since a RMS leak can end the life of a low value vehicle, since the repair could cost too much.
It never hurts to go back to a thicker high mileage oil to slow the leak if your trying to buy time. 10w40 high mileage could slow it some.
I hope your going to check the oil level more often than between changes now.
What synthetic did you switch to?
Nothing is likely to repair a RMS leak, even though some claim ATP-205 will fix a slower leak. If it's already on the chopping block with 173k , might as well try it since a RMS leak can end the life of a low value vehicle, since the repair could cost too much.
It never hurts to go back to a thicker high mileage oil to slow the leak if your trying to buy time. 10w40 high mileage could slow it some.
I hope your going to check the oil level more often than between changes now.
OVERKILL
$100 Site Donor 2021
Make sure its not the lower intake seal at the back of the block dripping down inside the bell.
Otherwise, change the RMS. It isn't a huge deal.
Otherwise, change the RMS. It isn't a huge deal.
Damage is done but go back to motorcraft leave syn alone
Some motors works better with a blend or dino
OVERKILL
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Originally Posted By: Ram01
Some motors works better with a blend or dino
It's a 5.0L Ford, it'll work fine on pretty much anything. And that statement makes zero sense.
Some engines may call for a synthetic, most non-Euro engines will be fine on dino of the right grade changed at a sane interval. But how they "work" isn't dictated by the type of oil that is in them.
Some motors works better with a blend or dino
It's a 5.0L Ford, it'll work fine on pretty much anything. And that statement makes zero sense.
Some engines may call for a synthetic, most non-Euro engines will be fine on dino of the right grade changed at a sane interval. But how they "work" isn't dictated by the type of oil that is in them.
OVERKILL
$100 Site Donor 2021
Originally Posted By: Ram01
Damage is done but go back to motorcraft leave syn alone
What damage?
Damage is done but go back to motorcraft leave syn alone
What damage?
Originally Posted By: Ram01
Damage is done but go back to motorcraft leave syn alone
No damage is done.
Most people assume that it is a myth, but some times switching to a synthetic will cause a temporary leak. Don't worry about it and keep the oil topped up. After an OCI or two of synthetic oil, the leak will stop.
Damage is done but go back to motorcraft leave syn alone
No damage is done.
Most people assume that it is a myth, but some times switching to a synthetic will cause a temporary leak. Don't worry about it and keep the oil topped up. After an OCI or two of synthetic oil, the leak will stop.
OVERKILL
$100 Site Donor 2021
Originally Posted By: Gabe
Originally Posted By: Ram01
Damage is done but go back to motorcraft leave syn alone
No damage is done.
Most people assume that it is a myth, but some times switching to a synthetic will cause a temporary leak. Don't worry about it and keep the oil topped up. After an OCI or two of synthetic oil, the leak will stop.
Yup, or will clean up some varnish that exposes an existing leak.
Originally Posted By: Ram01
Damage is done but go back to motorcraft leave syn alone
No damage is done.
Most people assume that it is a myth, but some times switching to a synthetic will cause a temporary leak. Don't worry about it and keep the oil topped up. After an OCI or two of synthetic oil, the leak will stop.
Yup, or will clean up some varnish that exposes an existing leak.
If your not going to repair the leak, might as well go with a 5w30 high mileage, M1 High Mileage if you want a synthetic, or any name brand HM conventional/blend, Pennzoil HM is another good choice.
Originally Posted By: OVERKILL
Originally Posted By: Ram01
Damage is done but go back to motorcraft leave syn alone
What damage?
Well I think the working theory is some crud was blocking a RMS leak and the synthetic knocked it loose and now it's leaking a quart every 2000. So the damage is that dissolved crud. I wish there was actually an oil that cleaned that well. I think it's probably a coincidence. I'm not sure what synthetic oil it was but I find it hard to believe a group 3 based oil would affect the seals any differently than any conventional.
Originally Posted By: Ram01
Damage is done but go back to motorcraft leave syn alone
What damage?
Well I think the working theory is some crud was blocking a RMS leak and the synthetic knocked it loose and now it's leaking a quart every 2000. So the damage is that dissolved crud. I wish there was actually an oil that cleaned that well. I think it's probably a coincidence. I'm not sure what synthetic oil it was but I find it hard to believe a group 3 based oil would affect the seals any differently than any conventional.
I hope you do not any damage. Maybe the its the change in oil. But if you never had a problem with motorcraft stay with it
I had a 2002 f150 I bought used that would smoke after using synthetic oil for 2 or 3 oil changes using Pennzoil Ultra/Mobil 1 HM. It cleaned the deposits from around the valve seals causing oil to slip by and smoke on take off after idling for a min. I would periodically check under the valve cover for signs of clean up. It never smoked bad enough to bother me just a small poof and the engine was smoother and started easier than when I bought it.
Which synthetic oil did you switch to? I don't see that mentioned in the opening post. All I see is that the car has had Motorcraft 5w30 most of its life and then started leaking after being switched to an UNKNOWN synthetic.
Goes to prove what worked for 170000+ miles why change at that stage of engine life.
False seal or not, using my impeccable 20:20 hindsight rear view observer, even if the leak stops it was not worth it in this instance to changeover.
False seal or not, using my impeccable 20:20 hindsight rear view observer, even if the leak stops it was not worth it in this instance to changeover.
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Originally Posted By: OVERKILL
Originally Posted By: Ram01
Damage is done but go back to motorcraft leave syn alone
What damage?
Agreed, WHAT damage???????????
The 5.0 has a one piece RMS that responds nicely to a high mileage oil... Also as mentioned check the seal under the rear of intake, it's common to leak(shape distorts) and be mistaken for the rear seal... No, high mileage oil probably won't fix that...
Originally Posted By: Ram01
Damage is done but go back to motorcraft leave syn alone
What damage?
Agreed, WHAT damage???????????
The 5.0 has a one piece RMS that responds nicely to a high mileage oil... Also as mentioned check the seal under the rear of intake, it's common to leak(shape distorts) and be mistaken for the rear seal... No, high mileage oil probably won't fix that...
you need to monitor oil level more.
and like others have said the leak could be temporary.
if you have a stash use what ever you have and monitor level.
and like others have said the leak could be temporary.
if you have a stash use what ever you have and monitor level.
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