5w40 / 5w50

[GEOMETRODUDE]

I have a FIAT 1.4L turbo 6spd that calls for 5w40 I've used premium brands and store brands 5w40 and when i do the UOA it always shears down to more a 5w30. Im worried about long term wear since the oils keep shearing down.

My question is would using a 5w50 help stop this? (Logically wouldn't it shear to a w40?) Appreciate the info

 

[Oillover]

How long are your OCI's?
What temps are you running in?

 

[GEOMETRODUDE]

How long are your OCI's?
What temps are you running in?

3k miles between changes and according to the vehicle it runs no hotter than 175F winter and 200F summer

 

[wpod]

Give it a try.

 

[Oillover]

Give it a try.

+1

Worst case scenario is it'll burn a bit more fuel

 

[blufeb95]

If the engine is spec'd for 5W40, don't you think they probably accounted for the shearing down during the OCI in the spec, there's not many 5W50 oils out there, and they tend to be racing oils that aren't intended for long OCIs or there was that 5W50 ford had for certain high performance engines but I think that stuff is known to be pretty not shear stable.

 

[Oillover]

If the engine is spec'd for 5W40, don't you think they probably accounted for the shearing down during the OCI in the spec, there's not many 5W50 oils out there, and they tend to be racing oils that aren't intended for long OCIs or there was that 5W50 ford had for certain high performance engines but I think that stuff is known to be pretty not shear stable.

Castrol makes a 5w50 that's pretty common up here in Canada.
No issue finding it at the local Canadian Tire
https://www.castrol.com/en_ca/canad...astrol-edge-brand/castrol-edge.html#tab_5w-50

 

[Rand]

3k miles between changes and according to the vehicle it runs no hotter than 175F winter and 200F summer

Sounds like coolant not oil temp.

 

[blufeb95]

Castrol makes a 5w50 that's pretty common up here in Canada.
No issue finding it at the local Canadian Tire
https://www.castrol.com/en_ca/canad...astrol-edge-brand/castrol-edge.html#tab_5w-50

That's that really basic SN rated stuff that's for a few Ford cars, I don't know about the Castrol, but I seem to recall the Motorcraft wasn't very sheer stable. There's a few 5W50 Porsche A40 oils out there I think, I don't know how easy they are to find where the OP lives, I assume somewhere in Europe.

 

[JavierH19]

A 30 grades worth of viscosity is still fine and I wouldn't worry about it. Someone on here has a turbo subaru that sheared the oil to near 0w-8 using a 0w-20. Now that's bad.

 

[Accent Abuser]

If the engine is spec'd for 5W40, don't you think they probably accounted for the shearing down during the OCI in the spec, there's not many 5W50 oils out there, and they tend to be racing oils that aren't intended for long OCIs or there was that 5W50 ford had for certain high performance engines but I think that stuff is known to be pretty not shear stable.

Mobil 5w50 is pretty good. Never seen it shear down below 14cst. The motorcraft 5w50 is garbage, it will very quickly shear down to 11cst.

 

[tundraotto]

just throw 15W-50 mobil 1 in it - it will shear too, but keep your OCI short....it's relatively cheap

 

[edyvw]

Run 5W40 or 0W40. What oils you used?
Can we see UOA?

 

[Vladimir Bonev]

Redline has 5W50, 10W50, 15W50 and a 20W50 if you wanna run a 50 weight that would not shear.
On the other hand, if you use a very good 40 weight like 5W40 or 10W40 (again Redline comes to mind) it should not thin out.
It is expensive though.

 

[shortyb]

Shear or fuel dilution? F/I engines can be notorious fuel diluters. And, a lot of 40wts. are on the thin side of the kV scale from the get go, so could thin to a "thick" 30wt. quickly then stabilize. 40wts. have pretty stout HTHS ratings, so I wouldn't worry too much unless its from fuel.

 

[TiGeo]

My turbo DI VW does the same thing as do others here. I've posted lots of UOA showing the same - 40ws down to 30ws by the end of even short OCIs. I stopped worrying about it. As shortyb above says, most of these are on the lighter side of a 40w and have a strong HTHS rating. Plenty of cars that run 30w or less all day.

 

[Accent Abuser]

just throw 15W-50 mobil 1 in it - it will shear too, but keep your OCI short....it's relatively cheap

Unless you're regularly below freezing.

 

[blufeb95]

The OP probably lives in Canada, now that I think about it, that's about the only place I can think of where you can get "store brand" 5W-40, assuming we're talking PCMO and not HDEO, so they probably don't want 15W.

 

[tundraotto]

The OP probably lives in Canada, now that I think about it, that's about the only place I can think of where you can get "store brand" 5W-40, assuming we're talking PCMO and not HDEO, so they probably don't want 15W.

If that's the case - I would use a block heater or a webasto - which in that climate is practically a necessity anyway.

 

[Snagglefoot]

I have a FIAT 1.4L turbo 6spd that calls for 5w40 I've used premium brands and store brands 5w40 and when i do the UOA it always shears down to more a 5w30. Im worried about long term wear since the oils keep shearing down.

My question is would using a 5w50 help stop this? (Logically wouldn't it shear to a w40?) Appreciate the info

You are reading something into this. When they “ call for 5w40”, they know it shears down to 30 grade. You are assuming they don’t know that and are worried about it. Fogetaboutit and enjoy your Fiat.