what weight oil to use for a 302 foxbody

[93calcobra]

got a foxbody which is the best weight oil to use some say 10w30 10w40 20w50 which is best? block only has about 20k on it

[82 GT]

It all depends on climate IMO. Since you you don't experience winters like I do here in Pa. then I would use 10w-30 or 10w40
20w-50 is for racing and very hot climates and a lot of stop/go driving.

[MEDIK418]

We run full synthetic in all the Mustangs at this house. 5w-30 in the winter ( and it does get cold here) and 10w-30 in the summer. I run Mobile 1 in me and Maw's vehicles and the boys both run Syntec in thier cars. I know, I probably just started a small war about synthetic vs. petroleum but this is what we use and it works to keep peace of mind.

[MidNiteBlu 5.0]

i use 10w30. I dont use synthetic cause my car has 100,000 miles on it hehe

[skiwesser]

Should I not put synthetic oil in a high milage car?
I was just about to.

[lx5091]

I've always run Mobil1 in everything I have. This has never caused any problems for me. I currently have 105K on the odometer. I change it at around 6000 miles, because it always has a lot of surfactant to it still and this is when it tends to start getting dirty. You want to change your oil when it gets dirty, because all oils are good enough these days to go 20K and still be slick, the problem is the detergents suck up the dirt in your engine and once they have captured as much dirt as they can then the dirt that cannot be "captured" by the detergents will float around in the engine and start to cause damage. When your oil gets dark it's time to change it, and I find that I can usually go 6K between changes using Mobil1.

[Mach 1]

I just switched to Mobil 1 0W-30 in my truck. Good stuff. Flows faster, better gas mileage, same great protection..

[MEDIK418]

THere was an argument years ago and I suppose it still surfaces now and again that synthetic oil in an old engine would all of a sudden cause multitudes of oil leaks. The argument was perpetrated mostly by people who didn't want to spring for the expensive stuff in an old car and needed an excuse not to do so. I suppose if you had a leak it might get worse, the stuff does flow better but, I've never seen this and I am running it in an engine with 186,000 miles on it right now.

True, running synthetic now after lots of miles won't undo any damage that's already been done and by no means am I asserting that petroleum based oils will damage an engine, I simply mean mileage is mileage, more miles means more wear, no matter which oil you run. However, starting life anew with synthetic oil in an old engine certainly won't hurt anything and perhaps (and I believe it will) it will last even longer than it would have otherwise. I say go for it.

[Mach 1]

Anybody else using 0W-30?

[95mustanggt]

Originally posted by MEDIK418
...( and it does get cold here) ...

COLD in Texas?!? When I lived in Dallas the parka's and mits came out at 55 degrees and every thing just about shut down at 32 degrees. Crap, I'll go out with just a T'shirt for quick erans (sp?) until 0-10 degrees!

Originally posted by Mach 1
Anybody else using 0W-30?

I don't, but where I'm from a lot of people do. In moy opinion, a good synthetic 5 weight is good enough for most of Southern Canada and the USA. People startedt o switch over to 0 weight oil once the temperature dropped below -30 to -35 degrees C. And even then, I found a good synthetic 5 weight was decent until that temperature. When you daily "high" (that's when the sun comes out and is beating down on you) only hits -35 or -40 you should switch.

[Mach 1]

Originally posted by 95mustanggt
COLD
I don't, but where I'm from a lot of people do. In moy opinion, a good synthetic 5 weight is good enough for most of Southern Canada and the USA. People startedt o switch over to 0 weight oil once the temperature dropped below -30 to -35 degrees C. And even then, I found a good synthetic 5 weight was decent until that temperature. When you daily "high" (that's when the sun comes out and is beating down on you) only hits -35 or -40 you should switch.

My trucks owner manual calls for 10w-30 or 5w-30 when very cold, as most cars today recommend the same weight oil.

However, my truck has a TSB (technical service bullutin) issued by the manufacture for a "valve train noise" problem caused by overhead cam engine and hydraulic valve lifters getting air stuck in them and not bleeding out properly or quick enough after startup.

The TSB says to use "mobil 1 0w-30" even though the manual calls for 10w-30, and that it still provides all the protection needed as 10w-30 with the additional benefits of faster flow when the engine is cold.

food for thought, as cold start up wear is the major cause of engine wear.

[2FastLX]

I switched to Mobile 1 tri-synthetic oil after 135,000 miles and never developed one leak. But then again it never had any leaks before I switched. But I agree with Medic. If you have a leak already it will probably get worse.

There is also a slight performance gain to be had with synthetic oils. I saw an article where they gained 8rwhp by switching all the fluids to synthetic. That's not a lot, but every little bit helps.

Another benefit is the cleaning power of the Mobile 1 oil. I religeously changed my oil every 3000 miles with the petroleum based oil. When I pulled my valve covers there was a slight film of sludge. I switched to Mobile 1 and ran for around 5 more oil changes or so (at 4000-5000 miles between each oil change) then had to pull my heads to replace the head gaskets. To my amazement when I pulled the valve covers they looked like a brand new set of heads. Not a spec of sludge to be found anywhere. Even the lifter valley looked like a freshly cleaned block. I was very impressed and now swear by this stuff. It may be more expensive, but to me it's one of the best things you can do for your engine...high mileage or not.

Another thing that I think may have helped though is I was running the K&N oil filters. The oil seemed to stay clean longer when I swicthed to them.

[bottlebaby91]

I have seen dyno test that there is a 3-5 rwhp lose using sythetic on mildly built 5 litres, but you cant believe everything you read.

[347 on juice]

I use Amsoil 0-30 in my car and it works great. No leaks whatsoever. I would recommend synthetic to most anyone.

[82 GT]

Originally posted by 2FastLX


Another benefit is the cleaning power of the Mobile 1 oil. I religeously changed my oil every 3000 miles with the petroleum based oil. When I pulled my valve covers there was a slight film of sludge. I switched to Mobile 1 and ran for around 5 more oil changes or so (at 4000-5000 miles between each oil change) then had to pull my heads to replace the head gaskets. To my amazement when I pulled the valve covers they looked like a brand new set of heads. Not a spec of sludge to be found anywhere. Even the lifter valley looked like a freshly cleaned block. I was very impressed and now swear by this stuff. It may be more expensive, but to me it's one of the best things you can do for your engine...high mileage or not.

I've always ran Valvoline 10w-40 in my mustangs, and still do.
When I tore my 351 down this summer I did'nt find one bit of sludge in the lifter gally or anywhere else for that matter.
I agree the synthetics are better then petro. based oils but there are some excellent petro based oils out there if you don't have the cash for the synthetics.

[Mach 1]

Originally posted by 347 on juice
I use Amsoil 0-30 in my car and it works great. No leaks whatsoever. I would recommend synthetic to most anyone.

Yeah, i think 0-30 synthetic is the way to go. great stuff. this weight isnt available in dino oil is it?

[MEDIK418]

Yes it are cold here once in a while. This morning it was 17 degrees at my house and it's 5:30pm and a whopping 34 degrees now.

[Mach 1]

Originally posted by MEDIK418
Yes it are cold here once in a while. This morning it was 17 degrees at my house and it's 5:30pm and a whopping 34 degrees now.

You southern People have to realize something....cold to you is not cold to someone in Canada. Its all what your used too,.......

Ive seen people wear shorts when it was 34 degrees outside. Why you ask? Because it felt warm to them. when your used to temps. in the negatives, 34 degrees is time for a tropicana party..

[JaxTheDJ]

I have tried basically all the top brand oils and recorded time,temp and how well it stood up after 40 runs at the track,this is my result:
Best parrafin based oil(regular motor oil): Pennzoil 10w30
Best Synthetic Blend: Castrol 5w30
Best Full Synthetic: Royal Purple 5w15 ( best 1/4 times) overall

We tested 5 major brands on 2 almost identical Mustangs and these are the best WE found based on ET and durability.

I personally run royal purple in MY Stang. try your own tests and see what works best for you.

[MEDIK418]

Yeah, but it was in the 80's here a couple of days ago. I grew up in Maine and you is right. Them Eskimos up yonder can have the cold stuff.

The cold here is nice because it only lasts a couple of months and it's back to the good stuff. I think the longest cold spell I can remember right off was one in 1982, December 16 the temperature fell to 6 degrees and that was the high for about 2 weeks. The bad part is the 30-60 mile an hour winds we have here. See, we're up here in the part of Texas that borders with Alaska. The only thing between us and the North pole is a barbed wire fence and most of it's down.

FYI, we use Royal Purple in every piece of rotating equipment in our refinery and the reliability folks swear by the stuff.