Accidental Oil Mix

maxnero81

New Member
Dec 13, 2008
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I have a 2009 Mustang GT AOD and I accidentally added a quart of Mobil 1 5w30 when the car had 1500 miles on it. It has 3000 now and I realized what I did so I let the oil drain for an hour and then added 6qts of Mobil 1 5w20. I'm still breaking it in so I haven't been hard on it. Do you think I did any real damage to the motor?
 
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Why'd you add oil to it?

And why do you think it damaged it, because of the weight, or because it was synthetic? Either way, I would not worry one bit. The factory oil is synthetic blend, so it will be fine, and the weight difference won't hurt anything, especially not one quart.
 
If the engine did not need any additional oil when you added a quart at 1500 miles, then doing so can overload the PCV system and overpressurize the engine's oil sump area, possibly causing the engine oil seals to fail. If you do not see any oil leaking from below the engine, then the seals are ok.
 
I know of quite a few people that run 5w30 in their cars, and I have heard that mobile one's 5230 is fairly close to a 5w20 in viscosity. I wouldn't worry about it, though like the others said, why did you add oil, or do you mean you just changed it?
Dan
 
Why'd you add oil to it?

And why do you think it damaged it, because of the weight, or because it was synthetic? Either way, I would not worry one bit. The factory oil is synthetic blend, so it will be fine, and the weight difference won't hurt anything, especially not one quart.


It was down a quart around 1500k so that's why I added it. It hasn't used any oil since then.
 
the VCT is sensitive to oil, and requires 5-20 to operate properly. IMO, if you have not been hard on the car, it should not make a difference for one quart. just be sure to use 5-20 for the future, because i have heard of ford denying claims when the wrong oil has been used.
 
bigcat,

I have heard the same about warranty issues, but I have my doubts as to if the dealership would really go as fas at to send the oil off the check it's viscosity. Not that big of a deal, but I would be somewhat surprised if they would do it.

Also, does the VCT have enough range to cause valve to piston clearance issues? I know this is a problem with bigger cams, but I haven't heard of it with the stock cams. That's really the only place I see an issue, though it would have some effect on performance as it would change cam timing.
Dan
 
the VCT is sensitive to oil, and requires 5-20 to operate properly. IMO, if you have not been hard on the car, it should not make a difference for one quart. just be sure to use 5-20 for the future, because i have heard of ford denying claims when the wrong oil has been used.

I know this is slightly off topic but WTF? Every thread is peppered with reports about how lame Ford is when it comes to warranty claims. It seems the customer is subject to interrogation on every potential warranty issue so as if to hopefully get out of having to do any work on the cars whatsoever. Is this for real?

I'm afraid to do any mods to my car for fear of warranty denials...I already have an aftermarket shifter and am dreading if I need to go in for any warranty claims for the transmission or clutch. I installed sequential taillights and have read Ford needs it 'stock' if you have any electrical problems with the cluster or other systems (won't fix it under warranty due to mods).

Now there's no question that you should use the recommended viscosity oil but geeez...is Ford going to run an analysis on your oil every time you bring it in for an unrelated engine problem?
 
Now there's no question that you should use the recommended viscosity oil but geeez...is Ford going to run an analysis on your oil every time you bring it in for an unrelated engine problem?

if there is a costly engine component failure, some ford field engineers will call for testing to be conducted. you increase the chances of this if the car is modded. :notnice: