10w-40 Or 20w-40

1989Gt. · December 11th, 2011, 10:12 PM

Was wondering if this would be ok to run in my pony to see if the oil pressure picks up.

1996 GT · December 11th, 2011, 11:01 PM

I have 10w-40 in the '08 GT, hasnt really been driven with it in due to the winter but sat and idled perfect for 10 minutes.

1989Gt. · December 11th, 2011, 11:21 PM

ok I figured it would be ok its not much thicker then 5w-30 that alot of people use... But i just wasnt sure.

1996 GT · December 11th, 2011, 11:24 PM

I have a guy i work with running 15w-50 in his '97 eclipse GST. Says the car loves it.

1989Gt. · December 11th, 2011, 11:30 PM

Well i just did a oil pressure test today and it just seems a little low. to me not too low but a little low

1996 GT · December 11th, 2011, 11:32 PM

Mines super lower right now, but ill be putting 10w-40 in it most likely also, if that doesnt bring it up time for a new oil pump or sending unit.

1989Gt. · December 11th, 2011, 11:36 PM

Whats yours at could you give me your specs.

Mine was 10-11 psi at 800 rpm

7-9 at 650 rpm

1500rpm 18-20psi
3000rpm was 30-35

1996 GT · December 11th, 2011, 11:42 PM

I'm on a stock gauge, i need a real one put in this winter. It sat at the "O" on NORMAL.

1989Gt. · December 11th, 2011, 11:46 PM

Woah woah woah you know that the stock gauge is just a switch right... You should be pretty worried because

The stock gauge reads 6 psi if its lower then that then your gonna have some problems.

1989Gt. · December 11th, 2011, 11:48 PM

its prolly your sending unit.

1996 GT · December 12th, 2011, 12:56 PM

Yeah ill be doing a sending unit this winter, and a proper gauge. I think i was loosing a little bit of pressure do to a leaky valve cover grommet, but thats no problem now.

blkfordsedan · December 12th, 2011, 08:34 PM

The valve cover has nothing to do with oil pressure. The oil pressure is the internal oil passages that feed the bearings. I would recommend replacing the sending unit or installing a real pressure gauge. Both are very easy to do on these cars. Running an oil with higher cold temp/cold start viscosity will only accelerate engine wear. If you really need a thicker oil due to high miles and increased bearing wear, I would recommend a 5W-40.

1989Gt. · December 12th, 2011, 09:10 PM

It's a fresh engine rebuild

1996 GT · December 12th, 2011, 09:38 PM

Yeah like i said i will be getting a sending unit, im starting the engine pull tomorrow, ill also be adding a gauge in also.

MustGT98allday · December 12th, 2011, 10:12 PM

instead of using thicker oil i would find the real problem of the oil pressure. dont just use wrong oil cuz you want to boost up the pressure. change the gauge and sending unit first and then go from there

1989Gt. · December 13th, 2011, 12:19 AM

For the 3rd time I have been using a manual oil pressure gauge

Tang Stang · December 13th, 2011, 09:35 AM

In another thread you said that you're running bearing tolerances that are on the "tight" end of specs. If that's the case, I really wouldn't recommend increasing the oil viscosity.

Originally Posted by MustGT98allday

instead of using thicker oil i would find the real problem of the oil pressure. dont just use wrong oil cuz you want to boost up the pressure.

Agreed. Don't mask the real issue. If you assembled the engine with tolerances conducive to 5W-30, don't stick 20W-40 oil in it.

1989Gt. · December 13th, 2011, 06:18 PM

yeah I just asked my fathers friend what the tolerances were.

1989Gt. · December 13th, 2011, 06:41 PM

So the tolerances were between .0015 and .002 he said all of them were that close.

p4ndiamond · December 14th, 2011, 12:28 AM

neither....dont even consider it . seriously tho. 10w is not good startup protection at all. what is the PSI ... 9psi is minimal at idle.

December 11th, 2011, 10:12 PM	#1
1989Gt. Hardcore Enthusiast 1989 Mustang GT Join Date: Apr 2008 Posts: 2,799 iTrader: 0 reviews	10w-40 Or 20w-40 Was wondering if this would be ok to run in my pony to see if the oil pressure picks up. __________________ MM FOBRA CLUB MEMBER #1

December 11th, 2011, 11:21 PM	#3
1989Gt. Hardcore Enthusiast 1989 Mustang GT Join Date: Apr 2008 Posts: 2,799 iTrader: 0 reviews	ok I figured it would be ok its not much thicker then 5w-30 that alot of people use... But i just wasnt sure. __________________ MM FOBRA CLUB MEMBER #1

December 11th, 2011, 11:30 PM	#5
1989Gt. Hardcore Enthusiast 1989 Mustang GT Join Date: Apr 2008 Posts: 2,799 iTrader: 0 reviews	Well i just did a oil pressure test today and it just seems a little low. to me not too low but a little low __________________ MM FOBRA CLUB MEMBER #1

December 11th, 2011, 11:36 PM	#7
1989Gt. Hardcore Enthusiast 1989 Mustang GT Join Date: Apr 2008 Posts: 2,799 iTrader: 0 reviews	Whats yours at could you give me your specs. Mine was 10-11 psi at 800 rpm 7-9 at 650 rpm 1500rpm 18-20psi 3000rpm was 30-35 __________________ MM FOBRA CLUB MEMBER #1

December 11th, 2011, 11:46 PM	#9
1989Gt. Hardcore Enthusiast 1989 Mustang GT Join Date: Apr 2008 Posts: 2,799 iTrader: 0 reviews	Woah woah woah you know that the stock gauge is just a switch right... You should be pretty worried because The stock gauge reads 6 psi if its lower then that then your gonna have some problems. __________________ MM FOBRA CLUB MEMBER #1

December 11th, 2011, 11:01 PM	#2
1996 GT Traction...? 1996 GT/ 2008 GT Vert Join Date: Nov 2010 Location: Canada Posts: 2,207 iTrader: 0 reviews	I have 10w-40 in the '08 GT, hasnt really been driven with it in due to the winter but sat and idled perfect for 10 minutes.

December 11th, 2011, 11:24 PM	#4
1996 GT Traction...? 1996 GT/ 2008 GT Vert Join Date: Nov 2010 Location: Canada Posts: 2,207 iTrader: 0 reviews	I have a guy i work with running 15w-50 in his '97 eclipse GST. Says the car loves it.

December 11th, 2011, 11:32 PM	#6
1996 GT Traction...? 1996 GT/ 2008 GT Vert Join Date: Nov 2010 Location: Canada Posts: 2,207 iTrader: 0 reviews	Mines super lower right now, but ill be putting 10w-40 in it most likely also, if that doesnt bring it up time for a new oil pump or sending unit.

December 11th, 2011, 11:42 PM	#8
1996 GT Traction...? 1996 GT/ 2008 GT Vert Join Date: Nov 2010 Location: Canada Posts: 2,207 iTrader: 0 reviews	I'm on a stock gauge, i need a real one put in this winter. It sat at the "O" on NORMAL.

December 11th, 2011, 11:48 PM	#10
1989Gt. Hardcore Enthusiast 1989 Mustang GT Join Date: Apr 2008 Posts: 2,799 iTrader: 0 reviews	its prolly your sending unit. __________________ MM FOBRA CLUB MEMBER #1

December 12th, 2011, 12:56 PM	#11
1996 GT Traction...? 1996 GT/ 2008 GT Vert Join Date: Nov 2010 Location: Canada Posts: 2,207 iTrader: 0 reviews	Yeah ill be doing a sending unit this winter, and a proper gauge. I think i was loosing a little bit of pressure do to a leaky valve cover grommet, but thats no problem now.

December 12th, 2011, 08:34 PM	#12
blkfordsedan Enthusiast 2004 Mustang GT Join Date: Dec 2010 Location: Nebraska Posts: 684 iTrader: 0 reviews	The valve cover has nothing to do with oil pressure. The oil pressure is the internal oil passages that feed the bearings. I would recommend replacing the sending unit or installing a real pressure gauge. Both are very easy to do on these cars. Running an oil with higher cold temp/cold start viscosity will only accelerate engine wear. If you really need a thicker oil due to high miles and increased bearing wear, I would recommend a 5W-40. __________________ -Brian 2004 GT TR3650, MAC Straight Shot CAI, FRPP 70mm, TFS plenum, catted X-pipe, Pypes Violator polished 304SS cat-back, custom tuned by AM/Bama...... 4.10's - coming soon!

December 12th, 2011, 09:10 PM	#13
1989Gt. Hardcore Enthusiast 1989 Mustang GT Join Date: Apr 2008 Posts: 2,799 iTrader: 0 reviews	It's a fresh engine rebuild __________________ MM FOBRA CLUB MEMBER #1

December 12th, 2011, 09:38 PM	#14
1996 GT Traction...? 1996 GT/ 2008 GT Vert Join Date: Nov 2010 Location: Canada Posts: 2,207 iTrader: 0 reviews	Yeah like i said i will be getting a sending unit, im starting the engine pull tomorrow, ill also be adding a gauge in also.

December 12th, 2011, 10:12 PM	#15
MustGT98allday Hardcore Enthusiast 1998 Mustang GT Join Date: Aug 2010 Posts: 1,282 iTrader: 2 reviews	instead of using thicker oil i would find the real problem of the oil pressure. dont just use wrong oil cuz you want to boost up the pressure. change the gauge and sending unit first and then go from there __________________ pi swapped and dropped sn95

December 14th, 2011, 12:28 AM	#20
p4ndiamond Hardcore Enthusiast 1997 Pacific Green Cobra 14.80 No traction Join Date: May 2010 Location: New Orleans Posts: 1,216 iTrader: 0 reviews	neither....dont even consider it . seriously tho. 10w is not good startup protection at all. what is the PSI ... 9psi is minimal at idle. __________________ GT ENGINE (temporary) 4.30 Gears , 31 spline Moser axles , Detroit tru Trac diff, Jmod 4r70w , Pi intake Hitech stage 2 cam, Vortech V2 3.33 pulley. Alum drive shaft. Lowering kit x2 ball joints ,screamin demon coils, LCA "

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December 13th, 2011, 12:19 AM	#16
1989Gt. Hardcore Enthusiast 1989 Mustang GT Join Date: Apr 2008 Posts: 2,799 iTrader: 0 reviews	For the 3rd time I have been using a manual oil pressure gauge __________________ MM FOBRA CLUB MEMBER #1

December 13th, 2011, 06:18 PM	#18
1989Gt. Hardcore Enthusiast 1989 Mustang GT Join Date: Apr 2008 Posts: 2,799 iTrader: 0 reviews	yeah I just asked my fathers friend what the tolerances were. __________________ MM FOBRA CLUB MEMBER #1

December 13th, 2011, 06:41 PM	#19
1989Gt. Hardcore Enthusiast 1989 Mustang GT Join Date: Apr 2008 Posts: 2,799 iTrader: 0 reviews	So the tolerances were between .0015 and .002 he said all of them were that close. __________________ MM FOBRA CLUB MEMBER #1

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