Amsoil 5w30 or 5w40 for Saab Turbo?

[budopo]

I've got Amsoil euro 5w40 oil in my Saab 4 cylinder turbo (haven't done a used oil analysis yet). The other option per the owner's manual is 5w30. The pertinent specs are:

5w40:
HTHS 3.8
NOACK 10%
TBN 8

5w30:
HTHS 3.6
NOACK 7.1%
TBN 8.8

Most of my driving is around town, not too stressful, but some high speed highway road trips, some stop-and-go traffic, and some spirited driving. It looks like the 5w30 is the better choice, but how important is the slightly lower HTHS? Would 5w40 give a bit better wear protection? As for the 5w40, with summer heat (Maryland, so temps in the 90s are typical), would the higher NOACK of 10% and lower TBN be of concern (or would a shorter oil change interval take care of that)?

Thanks in advance

 

[VQLT]

I have a 99 Saab 9-3 that specs 10w40. I live in So. Cal so no cold start issues. I'm more worried about turbo heat so that is why i use 10w40 instead of 10w30. in fact, my owners manual specs 15w-40 if temps remain consistently above 60

 

[slacktide_bitog]

The 5w30 has a higher TBN and lower Noack, so it seems like a better oil

 

[Bailes1992]

Isn't the euro oil an ACEA C3 oil?

I'd be looking for a *w40 with ACEA A3/B4 for your car. How cold does Maryland get? Do you really need a 5w oil? Could you get away with something like a 15w40 HDEO

 

[Superflop]

Rotella t6 was maybe still is the darling os the saab tuner groups. I ran castrol 5-40 for a while and it seemed to like it in both my 2.3 and v6. Ive never put a gauge on it but alot of saab people say that 30 weights can give low oil pressure.

With that said im currently running kendall gt1 5w30 full syn dexos in mine. Im in the boost alot.

Given how hard these engines are on oil why are you looking at such expensive oil? Even with updated pcv these engi es demolish oils in short order. I was sending in samples but got bored with it saying to stick to near 5k intervals with what is now the old formula mobil1 0w40.

So now its just 5k oci with a stout filter and good but cheap full syn.

Btw to directly answer your question if i were to go amsoil and i have thought about it i would go 5w30 first and pull a sample at about 4k.

 

[dlundblad]

Originally Posted By: Bailes1992
Isn't the euro oil an ACEA C3 oil?

I'd be looking for a *w40 with ACEA A3/B4 for your car. How cold does Maryland get? Do you really need a 5w oil? Could you get away with something like a 15w40 HDEO


We don't have 15w40 A3/B4's here sadly.

Most are 0w40 and 5w40 and are marketed as Euro oils.

 

[mx5miata]

If the manual recommends 5w40 I'd stick with that for the warmer months, swap out 5w30 during the winter. I have a neighbor that owns and works on Saabs I've seen him throw away many empty 10w30 Qt bottles,the older Saabs see Shell newer Saabs Mobil or Castrol synthetic.

 

[RooflessVW]

What year is your Saab?

 

[budopo]

Thanks for all of the replies! It's a 2008 9-5. Owner's manual calls for 5w30 or 5w40, GM-LL-A-025 (which I understand has been superseeded by Dexos). It also calls for 0w30 and 0w40, but it doesn't get cold enough here (10*F once in a while, and trips to New York would also not get below 0*F).

The lower NOACK and higher TBN does make the 5w30 look like the better oil, but I was wondering about the lower HTHS, and if 5w40 gives better wear protection than 5w30 (at the expense of fuel mileage). Same with summer heat; which would be better, 30 or 40 weight?

 

[slacktide_bitog]

Originally Posted By: budopo
The lower NOACK and higher TBN does make the 5w30 look like the better oil, but I was wondering about the lower HTHS, and if 5w40 gives better wear protection than 5w30 (at the expense of fuel mileage). Same with summer heat; which would be better, 30 or 40 weight?


If they both meet dexos2, there is no problem even with the lower HTHS

 

[RooflessVW]

Run Mobil 1 0W-40, skip the Amsoil.

If you're dead set on Amsoil, I'd run their European 5W-40 Classic.

 

[nthach]

That Saab would have called for dexos2, which is for European gas engines and all small GM diesel engines.

I'd run a good Euro-spec xxW-40 in it.

 

[BrocLuno]

All my Saab 2.3T got was 5W-40. How many miles? Sold mine at 148K and change ... Running like a top

Has it had a pan drop to check the oil pump intake screen? They coke the pick-up is why they starve for oil. Run the best syn you can. You may not need 0W for cold, but it buys you a better formula most of the time.

Larger 3600 equivelent filter should fit right on there. Will be noisy on cold start if you don't have a really good anti-drain-back valve. Mine liked Napa Gold filters the best

 

[budopo]

It's got about 165,000 miles, and runs well (I bought it about 1 year ago). The sludge issue in the oil pick-up was fixed after the 2002 model year (mine is 2008). I've used Mann filters for the last couple of decades, and I'll probably switch to the larger ones when my current stash runs out. I've always just used 10w30 in my Saabs, but they were the older (pre-GM) ones.

From the responses, I'm going to assume 5w30 and 5w40 have similar wear protection and heat protection, and the different between HTHS of 3.6 and 3.8 is minimal, and a higher TBN and lower NOACK really just let me extend the oil change interval. Of course, I'll know a lot more after I do a used oil analysis.