Oil for 1998 mustang

[MetalSlug]

Oil for very high miles 1998 Mustang GT 4.6L automatic ( I know I know, but I preferd auto myself after having TOO many manual.

the engine and everything is completely stock, 190k miles, no leak, no oil burn.

Which oil is best for this, im thinking QS 5w30 and FL820s

Transmission is having a leak, but I will get it fix soon, which transmission fluid should I get ?

for rear end, I know back then ford recom 80w90, which should I use 75w90 or 75w140 ( mobil 1 )

car is mostly drive on sunday, put In Drive and cruise. Thanks all

 

[aquariuscsm]

If it were mine,I'd use a 10W30 in your fave brand,and Amsoil SVG 75W110 in the rear diff.

 

[JustinH]

You can run those early modulars with just about anything. Just keep the oil level up it will run forever.

 

[Kuato]

No engine oil leaks? Choose your favorite.

I would put the 75w90 in the differential.

 

[ford46guy]

Motorcraft 5W30 or if you want to be brave 5W20. Can't beat the price. Mobil 1 is great too. The issue with those motors as they age are the timing guides and top end, so a 5W may be a good choice.

Ford specs at least a semi-synthetic, so QS dyno wouldn't be my first choice (but it is probably fine).

 

[69GTX]

The pre-2000 4.6L modulars were designed on 5w-30, and most were later back specced to 5w-20. I'd go with 5w-30 in QSUD, PP, or PUP as they go on sale. I have a mix of PP 5w-20 and PU SRT 0w-40 that will probably end up in my 4.6L (net 30 grade). But, currently running PP 5w-30. Since PP and QS are on sale for the rest of this year at $2/qt (48 qt limit per customer) it's hard to use something that's $3-$5 per qt. This month AAP has a QSUD deal, jug + filter for $19.99....less $7 QS rebate nets you at $13.

Trans fluid? I'd go with any of these: WM SuperTech MercV ATF, Castrol Merc V ATF, M1 ATF. The first 2 meet the Ford Mercon V specs. Any quality Mercon V would probably do even if not certified (Valvoline, Pennzoil, Amalie, etc.). Those all have operating viscosities of 7 cSt. While everyone seems to love Max Life ATF I don't see how that with a 6.0 cSt viscosity meets Mercon V specs (and it's not certified). Changing it every 25K-30K miles is the important thing. Your '98 might have been specced on DEX 3/Mercon. Using the syn blend Merc V is an upgrade imo...though a quality Dex 3 would be fine. My 1997 4.6L automatic came with a Mercon spec. By 2000-2001 those same cars were upgraded to Mercon V.

 

[BrocLuno]

190,000 and I'd be using Rotella T6. Cheap enough and easy to get. Not the thickest 40 when hot, so it's a lot like a 30. Any sludge or varnish will slowly go away. Change it once a year.

Your choice on filter. I'd use Napa Gold (WIX) but any good filter will do. One with a good ACBV is best...

Tranny, what does owners manual call for? I use Dex/Merc in most stuff I have. yours may be new enough to need slightly better. Change it at least every 50,000. If it has not been done, it's time. When they do the leak, have them do a new filter too

 

[Lyman]

In the last 4.6 I owned I used QSUD 5w30, SuperTech MercV ATF, Mobil 1 75w140.

 

[Merkava_4]

If you're up over 200,000 miles, you might want to consider a 10W-40 to save the chain guides.

 

[53' Stude]

Nah, go with a 10w30 like Formula Shell or Chevron Supreme or maybe Rotella T5 10w30

 

[ford46guy]

I was told the faster oil gets to the top of those engines at startup the better. Everyone here seems to suggest thicker oil, just trying to understand if it is best for this application.

A Dealer once told me 10W40 will practically grenade the engine if you ever start it on a very cold morning. Guaranteed warranty denial. That is pretty extreme, but i see people are using thicker oils. If you go to a Ford dealer you are getting Motorcraft 5W20 in your modular, you can take that to the bank.

I know some modulars speced 5W50.

Here is a snippet from an article in Engine Builder Magazine:

Something else that must be taken into account with late-model, overhead cam engines is cold oil flow following a cold start. Overhead cams are a long ways from the crankcase, so it takes awhile for oil to flow up through the engine to the cam journals and followers. If the oil is too thick for cold temperatures, it increases the risk of seizing or damaging an overhead cam. Fill a stock Ford 4.6L with 20W-50 oil and crank it over on a cold morning and you might seize a cam. That’s one of the reasons why OEMs have gone to relatively thin 5W-20 motor oils in most late-model, OHC engines. Another reason is to improve fuel economy.


http://www.enginebuildermag.com/2015/08/motor-oil-issues/

 

[Branson304]

Valvoline MaxLife Synthetic Blend 5W-30, 10W-30 or 10W-40. $15.88/5 quarts at Walmart, FL-820S Filter is about $3.97 at Walmart also.

 

[69GTX]

Originally Posted By: ford46guy
I was told the faster oil gets to the top of those engines at startup the better. Everyone here seems to suggest thicker oil, just trying to understand if it is best for this application.

A Dealer once told me 10W40 will practically grenade the engine if you ever start it on a very cold morning. Guaranteed warranty denial. That is pretty extreme, but i see people are using thicker oils. If you go to a Ford dealer you are getting Motorcraft 5W20 in your modular, you can take that to the bank....


In the OP's state of Mississippi I would think it would almost never get cold enough where a 10W-30 synthetic wouldn't flow on startup. And certainly a 5W would cover any possibilities. 10w is tested at -30C. There's also the point to consider that the thicker 10W cold rated oil would cling/cushion those upper cam shaft parts/guides "better" than a 0/5w. So they would be there to help until pump oil flow got there.

Unless your 10w is required to perform at under -20F, I think it will flow fine from -10F and higher. And as long as it flows/pumps, it will reach the upper cam shaft and galleries at the same time as the 0/5w grades.

Using a relatively heavy oil like a 20W-50 or straight SAE 30 or 40 in one of these engines is asking for trouble.

No one here is suggesting to do that.

 

[Nickdfresh]

I'd go with a HM oil, probably Quaker State Defy 10W-30 in summer, and 5W-30 in the cooler months. MaxLife and PHM would be good too, Mobil 1 HM if you want to pay more or mess with rebates...

 

[Gene K]

1996 GT
330,000 mi
Valvoline Maxlife 5W30 every 6,000 mi for last 200,000 mi.
No consumption.
No leaks.
Original timing chain and guides.

 

[aquariuscsm]

My best friend had a 1996 GT 5 speed. Pennzoil yellow 10W30 every 3000 miles since new. Had 350,000 miles on it when he was rear ended on I35,which totaled it. Those engines are indestructible.