Oil recommendation for a 1984 VW Jetta 1.7L FI

[micmac]

Hello,
A colleague of mine is looking to change his oil on a 1984 Jetta with a 1.7L 4cyl with fuel injection. He doesn't have the manual and I am pretty sure the 10W30 they put in it last at the oil place near work is wrong. He's happy with 3000 mile OCI he says. I am trying to talk him into a synthetic oil. Would Mobil 0W40 FS be a good choice?

 

[RooflessVW]

Why synthetic? These engines are easy on oil, and your buddy's is almost certainly weeping/leaking from more than one gasket.

I would, and have, run Rotella T 15W-40 in those old single slammers for 5k/1yr. It's good for year round, keeps the oil pressure well within spec, and is $12/gal. You simply can't beat it.

 

[micmac]

Well I was thinking that since he does a lot of short trips, the 15W40 is very thick at start up. Like 120 cps at 40°C vs 70 for the 0W40. He'll never get the think oil up to temp.

 

[Lolvoguy]

Originally Posted By: rooflessVW

I would, and have, run Rotella T 15W-40 in those old single slammers for 5k/1yr. It's good for year round, keeps the oil pressure well within spec, and is $12/gal. You simply can't beat it.


Aside from my DD, Rotella is my oil of choice for anything over 15 years of age.

 

[RooflessVW]

Originally Posted By: micmac
Well I was thinking that since he does a lot of short trips, the 15W40 is very thick at start up. Like 120 cps at 40°C vs 70 for the 0W40. He'll never get the think oil up to temp.


And that's perfectly fine. There was no 0W-40 when the 1.7 was new. Using 15W-40 in all situations is perfectly acceptable.

You can run a 0W-40, but will see no tangible benefit from it aside from him being able to say, "yeah, I run full synthetic."

 

[69GTX]

Originally Posted By: rooflessVW
You can run a 0W-40, but will see no tangible benefit from it aside from him being able to say, "yeah, I run full synthetic."


How about the price benefit? M1 0w-40 is available at $8.70/gall through October. Even the decent conventional oils have a tough time matching that. You can brag that you run full synthetic, at a less than conventional price. Enjoy it while you can. There's no guarantee that the oil companies will continue sales on synthetics throughout future years. And from a startup point of view, the 0w will start easier than a 15w in sub-freezing temps.

 

[micmac]

69GTX, where are you finding M1 0W40 that cheap. Last month I bought a 5qt jug for ~$22 and felt like I got a deal. Is there some sort of rebate deal?

 

[JimPghPA]

A

 

[JimPghPA]

Is the 1984 Jetta with a 1.7L 4cyl with fuel injection turbocharged or NA?

 

[RooflessVW]

Originally Posted By: JimPghPA
Is the 1984 Jetta with a 1.7L 4cyl with fuel injection turbocharged or NA?


Doesn't matter. But, if it's factory then it is a NA 1.7l screamer, making all of about 85hp.

I'm going to keep saying 15W-40, even if it isn't what the OP wants to hear for whatever reason.

OP: Do you want individual opinions based on experience, or confirmation of yours?

 

[micmac]

Just looking for the wisdom of folks on the forum who have a lot more experience with the old VWs than I do. Yeah, 85hp sounds about right... when it was new. And it is NA.

 

[RooflessVW]

The big weird issue on these engines is the intermediate shaft (distributor drive) nose bearing. They are known to fail over time. If you pull the oil pan and find a bunch of babbitt, that's where it is coming from.

Half of my bearing was completely gone at 300k miles, but there was no slop in the bearing or leaking at the seal.

15W-40 is the oil I'd run, and for maintenance I would replace the CIS injector seals and cups, the valve cover and oil pan gasket (check for the bearing pieces) and I would also do the transmission drive cup seals as they are also know to leak out all your transmission/differential oil very very slowly over time.

 

[micmac]

And the 15w40 you'd buy is Rotella T above any other?

 

[RooflessVW]

Originally Posted By: micmac
And the 15w40 you'd buy is Rotella T above any other?


I normally see the best prices on Rotella T and it is my preferred brand, but Chevron Delo or Mobil Delvac would work just as well.

 

[69GTX]

Originally Posted By: micmac
69GTX, where are you finding M1 0W40 that cheap. Last month I bought a 5qt jug for ~$22 and felt like I got a deal. Is there some sort of rebate deal?


There was a Mobil 1 rebate offer back in March-May - $12 rebate/jug. Another one just started August 1st/2nd that's good to end of October. See the rebate thread. Rebates abound this year. It pays to keep an eye on the rebate/discount offer thread. You could return that Mobil 1 you just got and then buy another with the current rebate(s).

 

[micmac]

The oil I purchased was from Walmart, and it looks like they don't allow those to get rebates. Nobody else around here has the 0w40 for less than $30 per jug.

 

[BrocLuno]

All the pre-2000's water cooled VW's I've owned, or dealt with, have got 15W40 HDEO for ever. Rotella is great for these engines, but Delo works fine too

You can usually fit a slightly oversized filter and that will reduce any tendency for cold oil to by-pass

If taken care of and fixed occasionally, they will run over 300,000 on HDEO

You're in western Oregon, not the arctic ... 15W is good down to something like 10 below before you need to get nervous. If it's cranking slowly, it is the ground circuits and corroded connections.