Oil in a GTV6 Engine

[Fylnn]

I am currently running Penrite HPR15 (15W-60) oil in the engine of my GTV6.  Bear in mind it is a rally car, and so does get the occasional bit of hard use.  Although pretty occasional so far this year.  It seems to work OK, doesn't burn a lot, engine maybe a bit tappety but then I gather they all are.  When I got it dynoed the guy said I needed a heavier grade of oil, because the gauge reads about 1-2 bar at idle on a hot engine.  When it is cold it reads about 7bar or just a bit over.  This is with a VDO gauge and sender mounted down on the oil filter.  I gave up on the vaguely Veglia's some time ago.  But reading the engine manual for the V6 the pressure is pretty low at idle anyway.

So not overly worried about anything, but coming up to oil change time wondering what to put I am wondering what to put in next.  Penrite now say either a HPR15 (15W-60) or a HPR30 (20W-60).  Reading other posts on this forum I notice a bit of a preference for HPR30 in most people.  So what do people commonly use in the 2.5V6?  It doesn't have to be Penrite either by the way. 

[Steve S]

I don't know much about oil for V6 TBH, but what does Alfa Romeo actually recommend?

1-2 bar at idle sounds fine for any engine. Is that what Alfa specs? Pressure at idle is mostly unimportant anyway. You want it to make good pressure at high rpm and load. Generally you need oil viscous enough to give 10psi more pressure every 1000 rpm. You don't want to so viscous that you risk the oil relief valve opening at high rpm, giving no pressure rise there on.

[Doug Gould]

Firstly, don't mix up SAE viscosity with film strength. Oils are complex things. There is an ACEA rating which represents film strength. SAE viscosity rating and a code for the additive pack (ie SM). I forget exactly how they all go. Personally, I'm not a fan of Penzoil. They use Mobil base stock and Lubrizol addiditive packs. I've tried a number of oils in my GTV6. It burnt a lot of oil with Mobil 1. Interestingly, it uses least oil with Castrol 5W 30 which is counter intuitive. I had a bunch left over from a test and so started using it. Its actually quite a "strong" oil and suitable for diesels. Before that my choice was Castrol synthetic 10W 60. The truth is, if you change it frequently enough it probably doesn't matter a lot. Personally, I reckon the thinnest oil that maintains oil pressure is probably best.

The different additive packs in oils can change carbon build-ups and therefore oil consumption initially. Its best to try and have a stable oil regime.

But then again, I could be wrong.

[wankski]

technically alfa specc'd 10w-50 or alternatively 15w-50 for the gtv6.

so the heaviest oil i would go for is a 15w-50.... better than that would be a 5w-50...

in the penrite range, i would suggest HPR10..

http://www.penriteoil.com.au/products/engine-oils-~-automotive/hpr/hpr_10_full_synthetic

this is actually a very good oil, that meets alfa's specification, and contains zinc.

a 20w-60 will be far too thick on start up and you'll just be wearing your engine until it hits temp, and even that, the oil will be a bit thick... high oil pressure is not always good! it's the loss of pressure u need to worry about! that's it...

a thicker oil will give higher pressure but less flow at a fixed rpm than a thinner oil. it is flow, not pressure that prevents metal contact and excessive wear.

to give you an idea, the HPR30 is a whopping 64% thicker at cold temps than HPR10. U really want that running through your engine when alfa specc's a 10w oil?  btw, 'weight' is meaningless. the actually thickness if given in centistokes... HPR is around 132 cSt cold and 19 hot... comparedw with 216 cSt and 24....

HTHs...

[Beatle]

Penrite website shows:

GTV6 83-86  HPR15 or HPR30

GTV6 GP 86-88 HPR10 or Everyday 20W50.  I don't understand that latter recommendation, apart from viscocity it says that oil is not recommended for european engines.......

All the 75s (2.5, 3L and TS), and 164s show HPR10 or Everyday 20W50

The website doesn't seem to show the latest product packaging (the 'full zinc' statement) but I'd be sticking with HPR10. or 15

[colcol]

The Penrite 'everyday' oil is a cheap fleet car type that is 20-50 as competition for Valvoline and Castrol GTX volume sellers, not the best oil for your Alfa, go for the Penrite HPR series, and change it regulary, Colin.

[MD]

Irrespective of the oil type you elect to use, here's a little tip. The principle reason why you should change your oil as frequently as you can afford it is nothing to do with a loss of lubrication qualities of the oil.

It has everything to do with sulphur.

The sulphur burned in the fuel winds up as sulpuric acid in the sump. This stuff accelerates the wear of your engine faster than wankski knocks back a burbon and coke at the pub..

Frequent oil changes minimises the concentration..bdbdbdbder, yibbidda, that's all folks.

[Steve S]

Engine oil contains buffers to neutralise acids. It is only once the buffer is depleted that acid is a problem. So changing your oil before the buffer is depleted is really only wasting money.

Forget what Penrite recommend. What's more likely, Penrite know something all the other oil manufacturers don't or they are using old wives tales and misconceptions to sell their oil?

For a daily driven car, I would use a synthetic 5w50. If you want to use Penrite, I would use 0w50.  If you use the car more for racing and want the best money can buy, I'd look to something like Redline or Motul. Redline 5w40 will have similar viscosity to the original 10w50.

Don't worry too much about the idle pressure. If the pressure is low, using higher viscosity oil will only increase pressure, which counts for nothing. Higher pressure is not going to give the bearings any more oil, if anything less.

[GeeTV]

I've poured too much engine oil into my gtv6.
Will this cause any issues??... Do i need to empty some out or will it be fine??

[jazig.k]

How much is "too much"?

[GeeTV]

Can't tell you in liters but the level is more than 5ml over the 'max' indicator on the dipstick,... perhaps closer to 10ml.  I'll have another look tonight.

[GeeTV]

Yep, about 5mm (NOT ml) over the 'max' line on the dipstick.
I'm using Penrite HPR30.
This thread is 5 years old. Any new products or thoughts/experiences Alfisti would like to add?