oil

4dlvr · 10-01-2007, 06:42 PM

ive just bought some new oil, the guy recomended 20w50 penrite, i rekon thats way too thik as i was after 15w50 or even 10w50. does any one know what the best thickness for oil is? and will running a thick oil(20w50) do any damage? the car has 115,000km
cheers

rob_liss_lms10 · 10-01-2007, 06:53 PM

I use Penrite hpr5 which is 5 weight. afaik if the weight is to high you will put more strain on the seals. The ford book says 10/30 is standard. From what I have been told by a friend who is a ford mech, 5 weight is the way to go unless you are burning/using oil as youyr fuel econ will be better and performance can increase because the engine parts move free-er.

smally289 · 10-01-2007, 06:54 PM

With 115k on the clock I'd go for a 20/50. 15/50 may be ok, but it may eat 10/30!!

4dlvr · 10-01-2007, 07:06 PM

should i return the 20w50 for somthing thinner like 15w50 or keep it the same????

NeishaXR8_347 · 10-01-2007, 07:25 PM

Put in some Shell Helix Plus its semi syn and 15w-50.

The Monty · 10-01-2007, 07:28 PM

What does the 50 stand for? Its probably a silly question, but does it matter too much about the second number?

zippy450 · 10-01-2007, 07:52 PM

autobarn has in there books to run magnetic in it 15w40 i think

NeishaXR8_347 · 10-01-2007, 08:09 PM

10w-40 is Magna, The 50, 40, 30 part is the Hot viscosity in the summer months i would keep it to 40 as the minimum.

The Monty · 10-01-2007, 08:26 PM

Cool. Just wondering as I always just use 15W-50, GTX3. Seems to work fine, and you get it in 5.5L bottles.

RIPGMH · 10-01-2007, 08:38 PM

I only work with ISO viscosity grades, but I belive the bigger number is the oil at 0 degrees c and the lower number is 100 degrees c. Oil has to accomplish two things which are at odds with each other, it has to lubricate and reduce friction and at the same time seal itself against rings and valves.

Cooper69S · 11-01-2007, 01:03 PM

Quote:

Originally Posted by The Monty

What does the 50 stand for? Its probably a silly question, but does it matter too much about the second number?

the second number is the MOST important to look at. Its the viscosity (thickness) of the oil at 100*C (hot/running temperature). The first number (ie the 'W' or winter grade) is the viscosity of the oil when the oil is cold(at 0*C).
when the car is hot, the 5w-50, 15w-50, 20w-50 etc oils are all the SAME thickness. the difference between them is that the 20w-50 will be much thicker when cold than hot. the 5w-50 is still thicker cold than hot, but not as much and therefore easier to pump around the engine on startup.

Quote:

Originally Posted by smally351

With 115k on the clock I'd go for a 20/50. 15/50 may be ok, but it may eat 10/30!!

having over 100k on your car doesn't automatically mean you need to use thicker oil. my bro was using 5w-40 shell synthetic on a EF with 300k on it with no oil consumption problems... if your car isn't comsuming oil when using the recommended grade, its likely you don't need to change to a thicker - using oil thicker than you need to puts (a bit) more load on your motor, wearing it out earlier, higher fuel consumption and lower power

amiers · 11-01-2007, 02:30 PM

whats the go for a AU 5L?

smally289 · 11-01-2007, 02:33 PM

Thats why I said it may, not it will.
I don't agree with the thicker oil wearing the motor out earlier. Higher fuel consumption, maybe. Lower power, maybe, but not enough to notice.
I just dont think that a /30 oil will offer adequate protection for the bearings etc once the clearances open up a bit.

Cooper69S · 11-01-2007, 03:28 PM

Quote:

Originally Posted by amiers

whats the go for a AU 5L?

the manual (au2) says 10w-30 or 10?W-40 for non-xr v8's and 10w-40 for xr8 - not sure why the difference - maybe because the xr will be expected to have a harder life??
i'm using 10w-30 atm to see how it goes, but when i spoke to the Centre Ford service dept they said you may have oil consumption issues with a 30 grade, so they recommended use 40 - so far i haven't burnt any oil so i'll see what happens.

Quote:

Originally Posted by smally351

Thats why I said it may, not it will.
I don't agree with the thicker oil wearing the motor out earlier. Higher fuel consumption, maybe. Lower power, maybe, but not enough to notice.
I just dont think that a /30 oil will offer adequate protection for the bearings etc once the clearances open up a bit.

my knowledge on the subject is mostly from research rather than experience and i've only assisted in engine building, never actually done it all myself so i don't pretend to be always correct...
is it fair to assume that if your engine is not consuming oil, then the clearances are still good enough to run the original grade oil safely?

i don't dispute anything you said there, i was really commenting on the idea that seems to come up a bit that people think as soon as you're over 100k, you need thicker oil, and so they go from the originally-recommended-30-grade to a penrite 25w-60 or something - from one extreme to the other - when a 40 would probably have done nicely...

smally289 · 11-01-2007, 04:03 PM

Thats what the forums are all about, sharing knowledge gained either thru experience or research, and there will always be differing opinions.
I agree with what you said about the 100k mentality, it isnt the beginning of the end for the engine.
The use of /30 oils concerns me, only because manufacturers specify them to get better fuel consumption to help win the sales race, with little rergard to engine longevity. For long term engine protection i would prefer a /40 oil, and this is what I recommend to my customers, especially when they start to rack up a few km's.
When its 40+ degrees and you're cruising at 110kph for a few hours, maybe even towing a trailer or caravan, I'd like a thicker oil than 10/30 splashing around in my sump.
Dont get me started on 15,000km service intervals either!

Cooper69S · 11-01-2007, 04:16 PM

ok thats cool... so if i change my earlier question to refer to 40 grade, which is also recommended for most of the ford 6's and 8's i think (don't they usually say to use 30 or 40?)... so long as the engine isn't consuming oil, is it fair to say that regardless of the number of k's its done the 40 grade oil is still protecting the engine?
i guess if the rings were good but bearings weren't, then this test wouldn't work, so i suppose its a question what wears quicker - is it rings or bearings?

smally289 · 11-01-2007, 04:33 PM

/40 grade oil should be fine, yes.
As far as rings or bearings wearing quicker, thats a tough one! I suppose oil consumption will test the ring condition, and oil pressure would indicate the bearing clearances and therefore wear.
I'd be more worried about keeping the rotating parts in good condition, not waiting until they wear out, before choosing an oil grade.