what oil for a high mile motor.

product1620 · Post by **product1620** » Mon Feb 26, 2007 12:01 am

Non fiero related but, My 98 mustang is do for an oil change, and I want to know if I should run synthetic or just a quality conventional oil like castrol gtx, the reason im asking is because the car has higher milege, and ive heard that high mile motors like to leak when run with synthetic.

befarrer · Post by **befarrer** » Mon Feb 26, 2007 1:20 am

I would run whatever has been in it all its life. Maybe if the oil pressure is lower or leaks alot, I would throw in a bottle of lucas or stp or something like that.

Dirty Sanchez · Post by **Dirty Sanchez** » Mon Feb 26, 2007 11:20 am

Stay with the reccomended grade of oil for your engine. You can find sme specially formulated oil in the right grade for higher mileage engine. This oil has additives that help the seals swell and seal better.

Mach10 · Post by **Mach10** » Mon Feb 26, 2007 11:40 am

It's a mustang; run it with the oil that it deserves: Used fiero oil run through a coffee filter. :thumbleft:

Use the recommended specs, don't waste your money switching to synthetic, now. Synthetic is best saved for heavy duty, hard-use motors that generate shitloads of heat.

It probably won't hurt to run syth, but you won't really see any tangible benefit.

Shaun41178(2) · Post by **Shaun41178(2)** » Mon Feb 26, 2007 12:48 pm

if over 100k miles I would look at using at least 10w40. or 20-50 in hot weather.

As the motor gets older the bearing clearences get wider which means you need a thicker oil. Its a bit of insurance. I run 10-40 in my car even though spec was 5-30

Mach10 · Post by **Mach10** » Mon Feb 26, 2007 12:54 pm

^^^ But only if oil pressure is starting to dip.

My parent's minivan has 280k on the clock and has higher oil pressure than the other van which is sitting at 180 (but has been abused... badly).

It's a preventative maintenance thing, and really, unless the motor's already knocking, it's not going to change a lot *shrug*

If it IS knocking, pour in some roofing tar unti the noise stops, and then sell it :salute:

product1620 · Post by **product1620** » Tue Feb 27, 2007 1:13 am

I decided to run mobil 1 5w-30, the car has 131k on it, most of which are highway, the oil pressure is just a tad high, which makes me think that they were running a heavier weight oil, I don't want to continue running that, because its fucking cold here, and I don't want to strain the oil pump or risk dry starts.

Mach10 · Post by **Mach10** » Tue Feb 27, 2007 11:09 am

Heavier oil will hang out in the bearings longer, reducing dry starts... but the fucker will crank Sllooooooowwww.

That said, how are you defining "cold?"

product1620 · Post by **product1620** » Tue Feb 27, 2007 4:14 pm

20* and below, lows in the negatives.