[VT_SVT]

Hello,

New here, not new to working on cars. Hi guys, I just bought my first Mustang, a 1997 SVT Cobra. I've wanted a Mustang since I was a kid and am happy to finally be part of the community.

I have the 1997 DOHC 32 valve 4.6 Liter Cobra Engine in the car.

I don't have an owner's manual for the car so I am unable to determine if the previous owner was running the right oil. He was running full synthetic 5W-20.

I have searched all over the internet for the right answer and keep getting conflicting information. The online owner's manual for my model year says to run 5W-30, My Hayne's Manual says run 5W-30, when I called the Ford customer service Hotline they looked up the same online owner's manual that I did and said 5W-30. However, when I went to the parts department at a Ford dealership, they looked it up on their computer and said 5W-20. When I search on car part store websites (O'Reilly, Autozone, Advanced) they say 5W-20. When I search other forum posts some people say 5W-20, some say 5W-30.

If it is supposed to be 5W-30, would the engine have been harmed by the previous owner having run 5W-20?

I want to do an oil change on this car before I drive it anymore, obviously.

I hate posting the "What oil do I run?" question, but I NEED to know what weight oil I should be running in this car. I can't get a definitive answer anywhere.

Thank you for any and all help.

 

[Yadkin]

The Cobra was limited production, hand built motor so that's why you are getting different information. Start with what the PO recommend and monitor oil pressure. Should be at least 20 psi per 1000 rpm when hot. If lower than that, go to the 30 weight oil.

 

[crjackson]

Welcome VT_SVT and thank you for joining ALLFORDMUSTANGS!
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[VT_SVT]

The Cobra was limited production, hand built motor so that's why you are getting different information. Start with what the PO recommend and monitor oil pressure. Should be at least 20 psi per 1000 rpm when hot. If lower than that, go to the 30 weight oil.

Thank you for the response. I don’t have an aftermarket oil pressure gauge in this car, just the factory one in my gauge cluster, so I can’t take note of specific oil pressure readings in relation to engine RPM. However, I’ve never seen the needle stray from the “Normal” range on the oil pressure gauge (for the 3 days I’ve owned it).

I’ll keep my eye on it. In the meantime, is it safe to keep driving the car even if the 5W20 isn’t the correct weight?

 

[Yadkin]

Yes. You should always use the lightest oil that will keep the pressure within the correct range.

 

[Jercole0956]

I have a 96 Cobra. Owners manual says 5W-30

 

[145566]

Either will suffice.

 

[Cobrajet67]

Thank you for the response. I don’t have an aftermarket oil pressure gauge in this car, just the factory one in my gauge cluster, so I can’t take note of specific oil pressure readings in relation to engine RPM. However, I’ve never seen the needle stray from the “Normal” range on the oil pressure gauge (for the 3 days I’ve owned it).

I’ll keep my eye on it. In the meantime, is it safe to keep driving the car even if the 5W20 isn’t the correct weight?

I believe the oil gauge is just a glorified dummy light in your car just as it is in the GT. It's either on or it's off but would just sit in basically the same spot. I know that the non Cobra Mustangs don't actually display an actual oil pressure and I would guess that it's the same in yours but there's a chance that it actually reads it being that your engine is special, idk.
5w20 would be fine. No harm will come to your engine even if it specifies 5w30.

 

[Venompower]

Just make sure to use 7 quarts, the heads drain oil slowly and can lead to starvation and spun bearings.