longrunner1

Just picked up a concours condition 1991 944S2, getting it sorted out mechanically, researched the services records going back to the original owner, thru its life so far it has been serviced with mobile1, 20/50 original owner, 2nd owner 15/40, third owner 5/50 - 15/40, my mechanic suggested going with 0/40 synthetic mobile 1, will not be tracking car, will use my 944s for that. Any suggestions would be appreciated. Car has 87k original miles, oil pressure is 4-5 at speed, runs very cool, right now.

J Berk

A lot depends on where you live but I have always used 20W50 in my car.

PS - post some pics !

JET951

The owners manual that came with the 944S2 printed by Porsche states in the ambient temp range of between minus 10 deg cel to unlimited high ambient temps , either 15w-50 or 20w-50 .

These high loaded flat tappet designed last century Porsche engines rely heavily on high oil film strength engine oils for longivity .Remenber there is no oil pressure at the cam lobes to the hydraulic lifter faces , only splash , same goes for the timing chain & sprockets ( twin cam ) + valve guides + alloy pistons to the alloy bores ( Alusil ) & crank thrust bearings all these components rely on Oil Film Strength

There are only two ways to increase engine oil film strength }

A) Increase oil viscosity from say a 0w-40 to a 20w-50 if both these oils have the same levels of ZDDP , which is generally not the case as last century oils like 20w-50 are allowed more ZDDP

B) Increase the levels of ZDDP

Take one away = low oil film strength
Take both away = even lower oil film strength

So generally speaking a 20w-50 with decent levels of ZDDP ( which most do ) then you have a very good high oil film strength oil

We have seen many 944 ( single cam & twin cam ) engines at work over the years that have been on a so called synthetic engine oil in the viscosity ranges of less than 15w-50 ( meaning 5w-40, 10w-40 etc ) that have only travelled less than 40,000 kms & the cam lobes were trashed , along with the hydraulic lifter faces & the timing chain sprockets ( which are part of the cams on the twin cam engines)= big money & completely avoidable .

Note } in the Australian climate , these last century Porsche cars do not stay on 0w-40 viscosity for long , because once the engine core temp gets up ( oil temp) the oil pressure warning light comes on at idle & very low oil pressure all through the rev range , which in turn increases the risk of damage to no 2 conrod bearing at high RPM at high engine core temp .

On a 15w-50 or 20w -50 this is not the case
Where as the ones that have been on the 15w-50 & 20w-50 from new have little or no wear even at 300,00KMS.

As the car is in getting some work done now , I highly recommend to}

A) Remove the two engine bay fuel hoses & remove the painted magnesium alloy twin cam cams cover( rocker cover, except there car no rockers) & inspect the cam lobes for pitting ( very easy to do ) & inspect the condition of the timing chain teeth for excessive wear ( looking for excessive wear as if one is looking at a motorbike chain drive sprocket )

B) If the ( once white plastic) timing chain guides are dark brown in colour & if in doubt , remove the cams & replace the timing chain slipper guides ( available as a kit from Porsche ) & a new timing chain , all very inexpensive stuff & worth doing , we are now replacing these components every 150,000 KMS , because there has been a sharp increase in the little timing chains letting go( high mileage cars) and this causes destroyed cams & often destroyed head as well .

Naturally these inexpensive components should be replaced more often if the car , be it 944s , 944S or 968 do a fair bit of club track work

BikePilot

For temperate driving anything that ends in a -50 should be just dandy. For subfreezing weather I'd lean toward something with a 10w or smaller first number and 40w or larger second number. (e.g., 5w-50, 5w-40, 0w-50, etc.). I've got Mobile 1 15w-50 in the 968 right now and it seems quite happy. Note, with thicker oils its particularly wise to let the oil come up to to temp before running them hard.

John_AZ

JET951

Excellent --again!

My choice:


I previously used Castrol GTX 20-50 for years but the amount of ZDDP has been reduced by Castrol.

The argument on oil is ongoing. If you are concerned about engine longevity-use an oil with high ZDDP.

J_AZ

Mueller944s2

I agree, this is what I use too. I used Mobil1 15w-50 for years, but after I dropped in my 3rd engine I switched to this because my dad uses it in his 911s. I didn't want it to leak. Oil pressure is higher which is good, probably because it's not synthetic. I would definitely recommend the VR1 though.

michael2e

Curious about this also. I've been using 20/50 same as the old 951 but is there any benefit/downside to replacing one quart with some lucas oil? As someone said the oil flow into the head is splash. Do you guys hear much valve train noise when you get on the throttle? TIA

BikePilot

Throttle opening should have no impact on valve train noise. Maybe you are hearing detonation?

I use the VR1 20-50 in my Buell, it's good stuff.

longrunner1

Thanks for the input guys, I have been using 15w - 50w synthetic in my 1987 944s , which I have put 13k on her in the last year, no oil usage or leaks, so when my mechanic suggested 0 - 40 for the 944s2 which I just acquired, I got a little concerned. Will get some pics up when I get settled in, just moved to a new home. I like a 15w -50w 0r 20w - 50w in a synthetic, any pro" s or cons on synthetic or conventional. Funny I have always used 15w - 40w conventional oil in all my high revving 4 cylinder diesel skid loaders and my kenworth truck which really gets some severe duty. I realize these cars are a whole another animal though.

beamishnz

Interested in the comprehensive Jet951 post. I'm in North Island of New Zealand where temps sit in the -10 to +35C range which the manual recommends 10 W-40 grade which is what I use in my S2 and 944S. This is also recommended by our local Porsche specialist who says that the fully synthetic 5 W-30 oils such as Mobil 1 cause more leaks and 'other issues'.

I use Mobil 2000 10 W-40 and Valvoline VR1 10 W-40. Just looked at the containers and see that the Mobil is rated API SJ/SL/SM and the VR1 is 'lower spec' SJ. The owners manual states SE or SF which is lower grade than either the Valvoline or Mobil.

Interestingly there is a cautionary note on the API site re using SM oils in older cars - "API SM engine oil is backwards compatible. As such, it can be safely used in older vehicles. It should be noted, however, that the use of API SM engine oil in some older "muscle cars" with flat tappet camshafts, has been linked to premature wear. " Does this apply to our cars
??

For the record API state SM is for engines made 2011 or earlier, SJ pre 2001 and SE and SF pre '79 and '88 respectively.

Interested in Jet951's view whether semi synthetic 10 W-40 should have same issues as the fully synthetic 10 W-40's he referred to. Got to also remember that our max temps are lower than Sydney

Also does anyone know the ZDDP level of Mobil 2000?

Neither 20W -50 nor 15W -50 avaialble from either of our main oil retailers (SCA & Repco). Closest is 15W -40 and by far the most popular in the premium oils is 10W -40.

JET951

Hi beamishnz , yes premature wear in flat tappet design is directly connected to low oil film strength oils ,& yes the 944 ( all ) like the 928 ( all ) are high loaded flat tappet design .

I will never trust a standard street ( read emission low ZDDP ) 10w-40 unless the manufacturer of the oil states that the AW package is high in ZDDP which is not generally the case in this century 10w-40 street oils that are sold to the public for this century cars .

We even had a famous brand 15w-50 engine oil here in Australia at around the beginning of this century & this oil company thought it would be nice idea to drop the levels of ZDDP( with no fanfare) so this oil could meet the stricter ACEA emission protocols for some car makes that still had 15w-50 in their owners manuals for new cars from around 1999 to around 2002 ( aprox ) & yes all **** hit the fan we had a huge surge in badly worn cams , and no not think it happens overnight , it can take 20,000 or 30,000kms before its too late.
And yes the same oil company reinstated the earlier ZDDP levels after they found out( couple of years later) , and all this with a 15w-50 , that made quite a few of us very nervous even with a 15w-50 , it may of been a one off , but ?

The question is why does this century so called fully synthetic engine oils have or need any last century ZDDP AW ( Anti Wear ) package at all ?. One would think they would not need any of this last century AW ZDDP , because one would think the terminology " Fully Synthetic " would mean that it would have a built in high oil film strength by the expensive process of making it , but its not the case at all , these oil still need ZDDP , just have a look at " Racing " engine oils web sites( same oil companies) , because racing oils are exempt from the emission protocols they can & do use very good levels of ZDDP in the latest & greatest this century so called synthetic racing oils & because these oils are exempt , the oil companies are quite happy to mention things like high levels of ZDDP protection for high loaded flat tappet design .

I just took out an owners manual from a 1994 928GTS ( think of it as two 944S2's) and in the owners manual on the oil viscosity page it states from minus 10 deg cel to unlimited high ambient temp , first ( top ) line of the multi grade oils = 20w-50

Arominus

M1 0w 40 has a decent ZDDP level (1100ppm) and in a non track car should be fine. I've been running it in my S for a while now and everything looks good. I'll be switching to 20w-50 for my impending track days however.

JustinL

I use Mobil1 V-twin 20w-50.

princej

20w50 vr1 Valvoline here. 944 NA seems to like it. runs better with it.

wouldn't use anything else but 20w50

beamishnz

Interesting article on subject of ZDDP and low levels permitted in latest API SM rated oils. http://www.kirks-auto.com/Oil_101_byRobertKirk.html