• Mustang Forums
  • 1996 - 2004 SN95 Mustang -General/Talk-
  • SN95 4.6L Mustang Tech

When to come off full synthetic?

  • Thread starter Thread starter MoneygrubbinCar
  • Start date Start date Apr 3, 2011
M

MoneygrubbinCar

Member
Apr 7, 2007
155
2
19
Jacksonville
Apr 3, 2011
#1
  • Apr 3, 2011
  • #1
My cars gettin higher mileage around 80k now and I notice I'm developing a small oil leak on the underside probably the rear main seal and oil pan gasket. But I've always ran 5w 20 mobil 1 full synthetic. Would now be the time for me to switch to maybe a synthetic blend and a heavier oil? I plan on fixing them when the clutch comes due so I'm not to heavily worried about it as long as I got oil in the car with me. Like I say its ever so slight I lose maybe half a quart of oil every 3000-3500 miles. Anyways any input and replies would be great. Thanks!
 

evolucion311

Member
Mar 19, 2009
236
2
18
Apr 3, 2011
#2
  • Apr 3, 2011
  • #2
I don't see a reason to switch to dino oil. You can use a thicker viscosity oil that is still full synthetic.

I swear by using syn fluids... I have 141k miles on my original engine, t3650, and rear end. Thing runs like a champ.
 
M

MoneygrubbinCar

Member
Apr 7, 2007
155
2
19
Jacksonville
Apr 3, 2011
#3
  • Apr 3, 2011
  • #3
I've considered that as well which is why I question I rather stick to a full synthetic but how much heavier should and could I go? All my previous vehicles we're older and were satisfied with generic 10w30
 

bhuff30

Founding Member
Dec 11, 2001
6,037
35
129
Olathe KS
Apr 3, 2011
#4
  • Apr 3, 2011
  • #4
My '97 has 184k miles and still gets mobil 1 full synthetic. If you've been running synthetic, then keep running it. Your leak really is small at 1 qt per 3500 miles. If the mess bothers you, *borrow* a cookie sheet from your wife/girlfreind and set it on the ground where you normally park. That will collect the oil and keep your floor clean without getting in the way. Then, you'll have a perfect birthday/christmas gift idea.

You can try a higher viscosity, but I don't see any reason to. The engine will still leak, just *slightly* slower than before. Obviously, you just need to fix the leak. If it is a rear main leak, keep an eye on the clutch. Oil can ruin the clutch if it gets slung to that area.
 
M

MoneygrubbinCar

Member
Apr 7, 2007
155
2
19
Jacksonville
Apr 3, 2011
#5
  • Apr 3, 2011
  • #5
Will do, I do plan on fixing the problem but no point in doing so until the clutch is due in my eyes. Thanks for the input and advice I usually give my car a light cleaning on the underside wiping away oil and grime in that area way I know how progressively worse it gets or if other problems occur. Mostly irritated when I take my filter off always makes a mess . I'm a little bit of a stickler for a clean car. Anyways thanks very much I'll stick to what I use for now.
 
M

mr-mike

New Member
Jul 9, 2006
122
1
0
Apr 9, 2011
#6
  • Apr 9, 2011
  • #6
I have been off of it for about 40,000 I'm up to over 160,000 I use the hi-milage oil & a quart of Risolene .....it was good years ago & its still good ! I just drove up from Florida & she purred like new getting 22-24 MPG ....just did my oil change & it was clean I am good on changing oil on a regular basis ......I swear by Risolene..............I have lots of respect for the 4.6 & am looking for 250,000 ..... I drove a new 5.0 while down there handled nice didnt like the cab too crowded & the non locking acess to the trunk but it shifted good the 6 speed auto seemed sweet but the price tag was high & my 99 is still full of life ! so I punked out
 

crzyhrse99

Active Member
Mar 30, 2005
259
3
28
Kansas
Apr 10, 2011
#7
  • Apr 10, 2011
  • #7
Have 165k on mine and still runing Mobile 1 synthetic, so thats double what you have lol and no problems, would drive the car anywhere. I change it every 3k with mc filter and have never had to add oil in between.
 
You must log in or register to reply here.

Similar threads

A
2001 Mustang GT, scorched metal smell and noise from trans/diff?
  • AndyE2255
  • Dec 1, 2025
  • SN95 4.6L Mustang Tech
Replies
4
Views
443
SN95 4.6L Mustang Tech Dec 28, 2025
gkomo
E
2007 GT Stalls when lights or a/c turned on
  • ejscarfo
  • Jun 22, 2026
  • 2005 - 2009 Specific Tech
Replies
2
Views
119
2005 - 2009 Specific Tech Jun 29, 2026
ejscarfo
E
New Member with a 1992
  • Clutchfork
  • Oct 18, 2025
  • The Welcome Wagon
Replies
5
Views
290
The Welcome Wagon Oct 19, 2025
Clutchfork
Engine What engine oil are you running in your foxbody?
  • Mindseye007
  • Dec 9, 2023
  • Fox 5.0 Mustang Tech
  • 2 3 4
Replies
63
Views
16K
Fox 5.0 Mustang Tech Jun 5, 2024
limp
S
Engine Stalls when downshifting/coasting
  • Scott_S
  • Nov 5, 2025
  • Fox 5.0 Mustang Tech
Replies
11
Views
689
Fox 5.0 Mustang Tech Nov 6, 2025
Mustang5L5
Share:
Bluesky Email Share Link
  • Mustang Forums
  • 1996 - 2004 SN95 Mustang -General/Talk-
  • SN95 4.6L Mustang Tech
Menu
Log in

Register

  • Forums
  • What's new
  • Media
  • Resources
  • Contact
  • Sponsor
X

Privacy & Transparency

We use cookies and similar technologies for the following purposes:

  • Personalized ads and content
  • Content measurement and audience insights

Do you accept cookies and these technologies?

X

Privacy & Transparency

We use cookies and similar technologies for the following purposes:

  • Personalized ads and content
  • Content measurement and audience insights

Do you accept cookies and these technologies?