G12 Coolant, G50 Gear Oil

I don't know how it is in the USA, but here in europe you can buy pretty much anything, which is compatible with aliuminium. But there is not much point of doing this, because a bottle of G12+ concentrate costs here something about 7euros (~1.5liters), i need two of them for a complete change. And you do not need to do it very often.

Sounds like a drug store prices you have there :)

You don't need to do it at all, according to VW, but when someone puts windshield washer in the coolant tank, that's another story. I was under the impression that G12 is just another modern, long-life, silicate- and phosphate-free coolant, but I can't confirm that from any source.

Sounds like drug prices, all right. Don't know about the store part. I've got to believe that there is even less potential difference between synthetic 75W-90 gear oils than there is between different coolants. I can't imagine that VW actually sells any of the stuff at all -- a quart of Mobil 1 75W-90 is about $8.

Down here Hondas come with a pink stuff thts compatible and worth half.

You may want to look into what gear oil is required for your VW. My '03 Passat specs GL4. Mobil 1 75w90 is a GL5. They are not compatible. Many GL5 gear oils use sulphur-phosphorus (S-P) additives to meet the GL5 spec, which is corrosive to the yellow metals used in VW synchros. A GL4/5 gear oil MIGHT be compatible, if the manufacturer specifically states it is compatible with yellow or soft metals.

That's good advice -- however, VW doesn't specify what their G50 is, other than to say it's a synthetic 75W-90. I've also heard it said that GL-5 will cause problems in VW trannies because it's too slippery for the synchros to work correctly.

I don't like the business practice of being coy about the specs of your products so you can't identify alternatives, then warning against using anything but your products, and then charging outrageous prices for it. That ain't the cowboy way.

That's interesting. For example, the user manual of my VW Vento/Jetta clearly states, that gearbox needs a GL4 compatible oil. I would be surprised if VWoA handles that differently.

There is a general problem, that each oem/aftermarket manufacturer produces it's own coolant with it's own unique features. Just saying "silicate and phosphate free" is not enough, there are a lot of other important properties. It is vitually impossible for VW (and makes no commercial sense) to test a lot of aftermarket products for the compatibility, and then oficially bless each of them. It is actually a responsibility of the manufacturer. For example, here in europe you can buy a BASF "Glysantin", which claims to be compatible. But it does not make much sense, as it costs roughly the same.

And there is another thing: VW engines tend to run at fairly high temperatures, so it is very important, that a coolant has relatively high boiling temperatures. Try to ask for a G12+ concetrate, could be much cheaper.

It could well be, that VW does not want to sell that oil at all, as there is virtually no demand for it. Just some rare single cases (warranty, emergency etc), which force them to keep some small amount of it in stock. And if you sell a bottle or two per month, then the whole logistics starts to be really expensive. Maybe that's why this oil costs so much.

Not sure where you are located but if you're in the states, you might try

The OEM fluid is Pentosin G12 and German Auto Parts carries it for just over $8/1.5L bottle. You really don't want to play around with "equivalents" here. Just get the Pentosin G12.

Simple stealer mark-up. I'm sure that German Auto Parts can help you here as well.

- Charlie

What is the model and year of your vehicle, and the engine? After a quick Google search, I find references to VW G50 fluid being GL4.

'01 Jetta GLS, 2.0L engine. Transmission code indicates that G50 is the specified gear lube. Thank goodness -- G52 lube is $65 per liter, according to my local dealer.

Nowhere in my car's manuals does it indicate the gear-oil spec, and the Bentley manual simply describes G50 as 75W-90 synthetic. The only reliable-looking reference I found by Googling was in a discussion forum, the poster said he had received a letter from VW in response to his inquiry, and the letter stated that GL-4 should be used. Apparently, VW is somewhat reluctant to let this info out.

I took Charlie's advice and checked out German Auto Parts, and I see they recommend Red Line MT-90, which is a 75W-90 synthetic GL-4 oil. Less than 10 bucks a quart, looks like this is the way to go. I've looked around in local auto parts stores, and it's damned near impossible to find a synthetic gear oil that is not GL-5.

Just out of interest I just looked at my both VW and Audi user manuals, they both specify the gearbox oil in the same manner.

My manuals are in german, but I think there should be no significant difference. So, if you look at the "instructions of use" part (Betriebshinweise), then you will find the part called something like "the engine compartment" (at approx. 2/3 of manual), they they speak about the engine oil, viscosity, change intervals and specifications, and directly after this there is a chapter about the "gearbox oil". The first paragraph says "oil specifications" which says "API-GL 4 SAE 80 or G50, SAE 75W-90". The second paragraph explains automatic and so on.

The German and American manuals are apparently very different. Mine consists of a series of booklets in a ring binder. Booklet 3.1 is "Control and Operating Equipment." In it, on page 107, there is a section headed "engine compartment." It consists of nothing but warnings about working within the engine compartment. No lubricant information. In booklet 3.2, on page 35, there is a section headed "engine compartment," which is the same set of warnings, no lube data. On page 38 of booklet 3.2, there is engine oil data, specifying grades and weights. Immediately after that is cooling system data, beginning on page 42. There is no reference to transmission lubes, either in booklet 3.2 or in any other booklet or index. I'll swear on a stack of Bentley manuals, there is no gear lube info in the manuals that came with my car.

IIRC A few years back I researched the VW G11 and G12. I had one of the VW parts personnel look up the manufacturer of the coolant here in the USA. It was Valvoline. I called Valvoline and asked about this coolant to see if any other product they sold is compatible. I was informed that it was a special blend and was only blended for the VW/Audi vehicles. No other coolants that they sold were compatible. :-( Of course this may have changed some. I purchase Pensotine(?) compatible, which has VW and Audi on it, but it does not save me too much in $$$ than going to the dealer. But I did notice that regular green antifreeze has gone up in cost but the VW compatibles have not.

Well, there are a few:

Pennzoil Synthetic 75w90 GL-4 Amsoil 75w90 synthetic GL4 Royal Purple Max-Gear GL4/5 (75w90 claims to be safe for soft metals) Motul Motylgear is listed as a GL4/5, but I cannot get an answer out of them as to compatibility with yellow metals

Both of Amsoil's 75W-90 gear oils are GL-5. No dealer around here carries a Pennzoil 75W-90 with the GL-4 rating, it's all GL-5. There are no Royal Purple or Motul dealers around here, period. A lot of synthetic gear oils are marked "GL-4/GL-5" -- I think it's safe to assume that if it meets GL-5 requirements, and GL-5 can cause problems in VW transmissions, then those oils are not suitable.

All of the gear oils I listed above are GL4 or GL4/5 oils.

Pennzoil Synthetic GL4:

Motul Motulgear GL4/5 is available online at They recommend it for VW transmissions, but, as I said earlier, I have not received confrimation from Motul that it is safe for soft metals

Royal Purple Max-Gear:

with soft metals: vehicle's transmission specifies an API GL-4 gear oil. Can I use Max-Gear®?

Yes. Max-Gear® possesses both API GL-5 and GL-4 certification. Max-Gear® is formulated with Royal Purple's proprietary, Synslide® additive technology to provide the exceptional film strength necessary for GL-5 applications, yet it is noncorrosive to soft metals found in manual transmissions that specify a GL-4 rated lubricant.

Amsoil Synthetic GL4 75w90:

Like I said, a GL5 oil should not be used due to corrosive S-P additives. However, a GL4/5 gear oil can be used as long as the manufacturer states it is safe for use with yellow or soft metals, which are used in VW synchros.

In addition to Redline the oils listed above are at least the options available to you for replacing the gear oil in your Jetta. Take it for what it's worth, or just buy the VW OEM fluid--it's your choice. I researched this very same issue for my '03 Passat earlier this year, and I'm just sharing the results of my investigation. You're welcome to do your own research and reach your own conclusions.

Sorry, I can't help you with what is available in your local shops, but you can order some of these fluids online, or maybe even ask your local dealers to order them for you.

I'll be doggone. I was looking at this page:

and under "synthetic gear lubes," there's no 75W-90 GL-4 oil listed. The one you found is under "transmission fluid." You're a better web researcher than I am.

Don't get me wrong, I appreciate you taking the time to share your info. I'll probably go with the Redline, from germanautoparts.com.

Thanks for the info.

I looked at Redline MTL also, as I have used it in two previous vehicles (87 Ford and 95 Passat). It really improved the shifting in the Ford (T-5 tranny), but didn't seem to improve the Passat shifting at all, and I did notice some stiffness in the shifts when cold. Current VW owners report that the Motylgear fluid significantly improves shifting in the Passat, but I am reluctant to use it without confirming it is safe with soft metals.

I may try both Pennzoil and Royal Purple for a few thousand miles each, with the idea I can switch back to stock fluid if necessary. I would really like to try Motylgear, so I may also ask Motul again about Motylgear (I have already emailed them twice, but no response. But summer's over, maybe they are back to work).

Hmm, I've been putting MTL in VW transaxles for years ('84 GTI, '84 Scirocco, '89 GTI 16V, '89 Corrado G60) and in every case an improvement in shift quality has been noticed.

nate