Modern oil for 1990 VW Mk2 2.0 16V?

[JAG]

Their viscosity chart only makes sense if you assume the multigrades have horrible shear stability. Perhaps they did back then.

HTHS viscosity is largely what matters in terms of protecting the engine when warmed up. If it leaks, kinematic viscosity is what matters in terms of effect of viscosity on leak rate and higher kinematic viscosity can reduce oil consumption. Since you live where winter temps. are cold, I think an oil with a winter rating of 10 or less is ideal. For a less expensive option, I'd use Castrol Edge 5W-50. Edge 0W-40 and M1 0W-40 is as low as I'd go for HTHS. For a more expensive option, I'd use Redline 5W-40.
Castrol 5W-50: https://msdspds.castrol.com/bpglis/FusionPDS.nsf/Files/B85B27606403EF8080257FAA007243CB/$File/BPXE-AA5D5S.pdf
Redline 5W-40: https://www.redlineoil.com/5w40-motor-oil

 

[Garak]

I'm not sure how much they were paying attention to HTHS back then; Doug Hillary would recall more of that. It was just ordinary ILSAC products if using a 5w-30 or a 10w-30 and in North America, and "not" if using a 15w-40, the preferred grade, in North America. Now, there probably was some thought process there, at least if one looks at the chart and sees where the 30 grades' suitability ended, compared to what you'd see for an ordinary GM of the time, let's say. Also, note that at one time, 10w-40 was a problem child grade. Take a look at some historical SAE J300 charts, and you'll see that for quite a while, they didn't have to meet suitable HTHS requirements you'd expect for a 40 grade.

JAG's first sentence answers it. If it were me, and it was me at one time, I'd run something like 15w-40 when the climate permitted, or a 0w-40 or a 5w-40 year round. If I had it right now still, and I were looking at a year round fill given my climate, I'd run Shell Rotella T6 Multi-Vehicle 5w-30, Mobil Delvac 1 ESP 5w-40 (or any competitor's equivalent), or any of the 0w-40 or 5w-40 A3/B4 lubes, such as Pennzoil Platinum Euro 5w-30, Castrol 0w-40 A3/B4, or M1 0w-40. All these options have suitable winter starting numbers here and an HTHS of 3.5 or greater, which is sufficient. Don't worry much about kinematic viscosity. Pay attention to your winter number and your HTHS, and all will be fine. I'm sure the weaknesses in ordinary SAE grading were in the mind of European OEMs when they moved to proprietary specs.

The Red Line mentioned has HTHS elevated still more, and pricing is always an issue. Each example I listed are products I can get for roughly $30 or less a jug.

 

[FCD]

Originally Posted by edyvw
Originally Posted by tylerdurden
Hello everyone,

This is my first post, but I'm a long time lurker.

I've recently gotten back into Volkswagen Mk2 GTI's and would appreciate some input on what viscosity oil I should be using. The service manual recommends a high viscosity oil, and back in the old (pre-synthetic) days it seemed everyone ran Castrol GTX 20w-50.

My question is this: Did VW spec such heavy oil due to the limitations of conventional oils, or due to wider engineeering tolerances? If it's the former, am I good to use M1 0w-40, or Group IV Liqui-Moly 0w-40? If it's the latter then would M1 15w-50 be a good choice?

Here is a picture of the viscosity chart:


I had that car back in the days. It is great driving machine, and as someone said, in the 1990's driving 200km/h on two lane in Europe was normal, and that thing could do it, easily.
I ran good ole "black" Castrol 15W40 in that engine. You can run pretty much anything W40 in it, but considering your location, I would use 0W40 or 5W40 Castrol from Wal Mart. You could go cheaper, but why? Those oils are not expensive anyway.


You are aware that only Germany has autobahns and not all of Europe right?
Because driving 200 km/h was, and still isn't the norm, or even close in the rest of Europe.

 

[tylerdurden]

Garak/JAG,

Thanks for the replies.

I've been pouring through BITOG and have seen many a discussion that relate. And many helpful posts from both Doug and Garak. And I agree that JAG is exactly right about the original ambient temperature chart.

If ILSAC 10w-40 was a problem child then the chart really begins to make sense to me. It would seem evident to me that VW wanted a higher HTHS than an 80's era 30w ILSAC could provide. To me the chart indicates they predominantly wanted a 40w. But as ambient temps dropped to 0*F they caved in the interest of maybe protecting the engine at start up, but more likely just trying assure that the engine started at all.

On the other hand they were not confident that the 30w or even the 40w's could provide adequate HTHS back then so they were chasing HTHS with their 50w recommendation.

Which finally allows me to understand how Porsche, BMW, VW, all recommended heavier oils back in the day, but what they've ALWAYS wanted is the 5w40 and 0w40's we have today.

I've had limited experience with oils. A fair amount of M1 15w50, some short forays into redline and amsoil, a ton of T6 5w40, and a bit of 5w40 Edge. And just recently M1 0w40, which just seems like a miracle oil for my B7 S4. At $23 for 5q I'm sure it will be adequate for the 16V. Also going to test it out in the Subaru SVX powered Vanagon. None of these are high powered turbo charged cars that warrant Redline to me. And having one oil for everything would be very convenient.

 

[Garak]

When it comes to 30 grades, remember at the time of the writing of that page, most had lower HTHS, just like you'd see today with a 10w-30 or 5w-30 in SN/GF-5. You weren't seeing elevated HTHS 10w-30 options other than an HDEO, and things like Castrol 0w-30 A3/B4 weren't yet around. So, the easiest way to get an HTHS of 3.5 or higher was with a higher viscosity oil. 10w-40 historically has been a problematic grade. Even General Motors had warnings against that grade in its manuals for many, many years. Reading those manuals for years is probably what soured me on the grade.

M1 0w-40 would be just fine for that vehicle, too. T6 5w-40 would be fine, too. When I had my old Audi, I ran a 5w-30 one winter, as per the recommendations. That oil consumed like water, whereas 10w-30 did not, oddly enough. Shortly thereafter, I ended up going with a 0w-40 or 5w-40 synthetic, and that consumed much less.