Should you use synthetic oil on a high mileage motor? - Ford Mustang Forum
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post #1 of 6 (permalink) Old 07-18-2004 Thread Starter
Warloc's Avatar
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Should you use synthetic oil on a high mileage motor?

Just got back into building up cars...My latest project has 137k on it and still pulls strong with good oil pressure and no smokeing. I was thinking of running synthetic oil to help it out. Is this ok to do with a high mileage engine or should I just stick to a good milti-weight oil? Would a 20w-50 work better or a 10w-30? Any insight would help since I want to prolong going into the block for about a year if possible.
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post #2 of 6 (permalink) Old 07-18-2004
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I would use 10w30 full synthetic if you really want to help it out and have the money to spend on it. This will really baby it but you could get away with regular oil and maybe change the oil at 2,000 miles.

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post #3 of 6 (permalink) Old 07-18-2004
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I would run 20w50 if your car has 120k or more on it. Only if you are in an area where the temperature stays above freezing. Synthetics will show all the leaks your motor is about to get, rear main, valve covers, oil pan, etc... Just my opinion

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post #4 of 6 (permalink) Old 07-18-2004
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218k & Going Strong on Mobil 1


I bought an 89 Lincoln Mark VII LSC with 5.0 HO in the
mid 90's - it had 105k on it then and had not been babied.

I switched to Mobil 1 a few months later after reading
about it.

I now have 218k on the car and it's still running good -
uses normally not over 1/2 quart to 2500 mi oil change.
Have a little seepage at the front seal and valve covers,
but nothing unusual.

I've driven it fairly hard with lots of long 80+mph trips,
mixed with fairly cold weather 20 mile trips and 90 deg
plus summer driving with no problems.

I use 10W30 and do not have any oil pressure problems.
With the overdrive trans in cars now you don't run as
many rpms per mile so they don't wear as fast as they
used to, plus engines are built better and with better
quality parts, so wear is not as great at 100k as it was
not too many years ago. Besides, you're wasting
several horsepower and a little gas mileage pumping
heavier weight oil and it's harder on the distributor
gear and cam gear.
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post #5 of 6 (permalink) Old 07-19-2004
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I use Mobil 1 10w - 30 Full Synthetic

1995 5.8 GT Coupe / White / Tan Leather

All the normal goodies including a built C4, Kennebell Blowzilla @ 12lbs.

She spins!

11.7 @ 116mph
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post #6 of 6 (permalink) Old 07-19-2004
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my car has 155k on it and im using full synthetic on it 10w 30 seems to be doing fine

87 mustang gt 5.0 5 speed,Flowmaster,Bored .30 over ,BBK Shorty Headers,Steeda short thow,New engine fully rebuild pure carb..
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