What oil to buy now 10w 40 full syn Nulon is NLA?

[J_D 2.0]

Castrol Magnatec

I used to use Castrol Magnatec or Shell Helix (whatever was on special) in my old SV6. Never had a problem with it. Having said that I figured the SSV deserved the best and I went with the recommendations on here WRT Penrite HPR5.

 

[losh1971]

It doesn't make any sense re your experience with w ratings. This only pertains to the winter rating (cold start kinematic viscosity) and the difference between a 5w and 10w only really affects folk on startup who might live around the Arctic Tundra. I'm guessing it's more likely these are different formulas, which can account for consumption

I wouldn't go into using Penrite with preconceived notions. HPR5 is the one you want, it's a different formulation to the 10 and your probably not wanting a 50 weight on your big ends just yet. I wouldn't mix them either

I can try 5w when my supplies of Nulon run out and see if I burn oil. If it does then I will go to 10w.

 

[chrisp]

I can try 5w when my supplies of Nulon run out and see if I burn oil. If it does then I will go to 10w.

Did you have the valve stem seals replaced when you had the valve springs replaced?

 

[losh1971]

Did you have the valve stem seals replaced when you had the valve springs replaced?

No.

 

[chrisp]

No.

Oil use is usually either (a) worn bores/rings, or (b) (and more commonly) the valve stem seals in the inlet valves allowing oil in. (The exhaust valve stem seals aren’t so critical as the exhaust gas pressure stops the oil flowing down the valve stems).

The easiest and cheapest thing to try on an engine that is using oil is the valve stem seals. If it is still using oil after it has new valve stem seals, it usual to just live with it as the next fix is an engine rebuild.

 

[losh1971]

Yeah I'm not spending $800 or so replacing valve stem seals. Especially when it may not fix the oil use issue. And definitely not dropping $15k or so on a rebuild. 10w does the job so I'll stick with that.

 

[chrisp]

Yeah I'm not spending $800 or so replacing valve stem seals. Especially when it may not fix the oil use issue. And definitely not dropping $15k or so on a rebuild. 10w does the job so I'll stick with that.

Most oil use is usually valve stem seals. Excessive oil oil can eventually glaze the bores and result in oil use via the rings as well, it’s definitely one of those things that is better done sooner than later.

You could DIY for about $100 https://malexmotorsports.com/produc...e-stem-seals-full-set-ls1-ls2-ls3-l98-l77-l76

You’d already have most of the tools needed. The only special tool is a compressed-air valve ‘holder’ adapter (about $50), and some sort of head-on valve spring compressor (there are many types of these - some are specific to the LS).

You already have a wonderful collection of tools, so why not put them to use to make them pay their way? They’ll get a good job done for very little outlay. Why buy tools otherwise?

 

[losh1971]

10w is doing the job. Not interested in changing valve stem seals. I only do basic repairs now. What I've done for the last two years has worked so far so ill keep doing what I've been doing.

 

[losh1971]

It doesn't make any sense re your experience with w ratings. This only pertains to the winter rating (cold start kinematic viscosity) and the difference between a 5w and 10w only really affects folk on start up.

What doesn't make sense is what you've said.

A 10w is still thicker oil when hot than a 5w. Otherwise going but your logic a 15w 40 is going to be the same thickness as 5w 40 when hot. The first number is what matters if you want a thicker oil.

Happy to be proven wrong though.

 

[chrisp]

What doesn't make sense is what you've said.

A 10w is still thicker oil when hot than a 5w. Otherwise going but your logic a 15w 40 is going to be the same thickness as 5w 40 when hot. The first number is what matters if you want a thicker oil.

The first number is the cold viscosity (-35C to -10C). The second number is the hot viscosity (at 100C). If they are both ‘-40’, then they should both be behaving like a ’40’ weight single-grade oil at operating temperature.

’Multigrade’ oils change their viscosity according to the temperature. So a 5W-40 behaves like a 5-weight oil when cold, and a 40-weight oil when it is hot.