Is EP 90, GL-4 Okay To Use In A 1987 Cobra Outdrive?

[DavidW2009]

I recently drained and refilled the Cobra (standard with 2.3L Ford) outdrive with EP 90, GL-4 rated gear lube. (EP = Extreme Pressure). Rereading the OMC specs, I realised it calls for a GL-5 rated lube. I see nothing about an EP rating, either.

The boat is not sea-worthy, so it hasn't been to the water. I've run it a max. at 1500 RPM briefly, and mostly at idle for a total of 15 minutes since adding the fresh oil. I don't believe I've hurt anything, and I'm willing to drain it and refill it with GL-5.

But I'd like to know if there is a technical problem with using EP 90 GL-4 in a Cobra. This lube does have some good properties to it. It is also had to find, if not impossible. But I still have an unused gallon of it.

Thanks.

 

[havasuboatman]

Re: Is EP 90, GL-4 Okay To Use In A 1987 Cobra Outdrive?

I personally put OMC hi vis drive oil (or Sierra's equivilant) in mine which is what the manufacturer recomends

 

[bruceb58]

Re: Is EP 90, GL-4 Okay To Use In A 1987 Cobra Outdrive?

Get some GL5 75w-90 Mobil-1 at the auto parts store and you will be fine.

 

[zbnutcase]

Re: Is EP 90, GL-4 Okay To Use In A 1987 Cobra Outdrive?

With that no (oops) I mean low power engine you will be fine, assuming you filled it CORRECTLY! 'nutcase

 

[DavidW2009]

Re: Is EP 90, GL-4 Okay To Use In A 1987 Cobra Outdrive?

zbnutcase,

I did a modified fill procedure. Loaded it from the bottom drain until it came out the middle fill hole. Then finished filling from the middle. Took 64 ounces and is above the ring mark on the dipstick (not screwed in).

Then came back after a couple of days and rechecked the dipstick. Still above the ring mark.

The OMC manual says 60 ounces for the 1987 Cobra. But it seems like most put in 64 ounces.

As for low power, I've been theorising that since this is the same outdrive used on higher HP models (ratios may differ), then maybe, if taken care of, it should hold up better. No? Should hold up like the venerable Volvo-Penta.

Edit: The omc manual does not specify how much grease to use to lube the gimbal bearing. It states to lube it when the drive is off and make sure the old grease is pushed out. Can't see that when the drive is in place, so I put (5) grease pumps into the zerk.

 

[JustJason]

Re: Is EP 90, GL-4 Okay To Use In A 1987 Cobra Outdrive?

I put Merc HP gear lube in everything that does not specifically call for something other than gear lube.

 

[bruceb58]

Re: Is EP 90, GL-4 Okay To Use In A 1987 Cobra Outdrive?

I did a modified fill procedure. Loaded it from the bottom drain until it came out the middle fill hole. Then finished filling from the middle. Took 64 ounces and is above the ring mark on the dipstick (not screwed in).

Curious why you would not follow the instructions that the factory manual says to do when you fill which is fill from the middle.

 

[Lou C]

Re: Is EP 90, GL-4 Okay To Use In A 1987 Cobra Outdrive?

I also use the Merc Hi Perf gear oil at my mechanic's recommendation and it's worked great in my Cobra over the years...the OMC HiVis is not that easy to find although West Marine does sell an aftermarket version and Pennzoil makes one too...I do think there is a benefit in using a marine rated lube because of the issue of possible water intrusion during the season...

 

[DavidW2009]

Re: Is EP 90, GL-4 Okay To Use In A 1987 Cobra Outdrive?

Curious why you would not follow the instructions that the factory manual says to do when you fill which is fill from the middle.

I reason that there is more likelihood of entrapping air in the lower half when filling only from the middle. There are pockets down there where that looks like it could happen. I'm adding another step, but the same 64 ounces gets into the unit. That's what's important.

 

[DavidW2009]

Re: Is EP 90, GL-4 Okay To Use In A 1987 Cobra Outdrive?

I also use the Merc Hi Perf gear oil at my mechanic's recommendation and it's worked great in my Cobra over the years...the OMC HiVis is not that easy to find although West Marine does sell an aftermarket version and Pennzoil makes one too...I do think there is a benefit in using a marine rated lube because of the issue of possible water intrusion during the season...

I just did some more reading on gear lubes and the differences between GL-4 and GL-5. GL-5 has sulphur added to it to give it it's EP rating. Apparently, GL-5 has EP included in its spec.

I now also think there is a difference between GL-4 (has very little sulphur in it) and EP GL-4 which does have sulphur. See this quote:

"To give the gear oil its EP rating, it's trationally been easiest to add a sulpher based friction modifier like MoS2 (molybdenum disulphide) but the broken down sulphur left in the oil (you can smell it) has in the past been responsible for corrosion and pitting of the vintage copper alloy that was used to make the VW synchros."

The EP 90 GL-4 I'm using is 30+ years old. Maybe back then there wasn't a GL-5 rating, but there was a difference between GL-4 and EP GL-4 (?). I don't remember. I have found out this EP GL-4 is okay to use in the old Chrysler O/B lower ends.

I'll use what I've got for muff testing. Whe it comes time to go to the lake, I'll put some Quicksilver or equivalent in it.

 

[bruceb58]

Re: Is EP 90, GL-4 Okay To Use In A 1987 Cobra Outdrive?

I reason that there is more likelihood of entrapping air in the lower half when filling only from the middle. There are pockets down there where that looks like it could happen. I'm adding another step, but the same 64 ounces gets into the unit. That's what's important.

The whole reason that the factory OMC manual states to fill from the middle is to avoid just what you are trying to avoid. You should fill from the middle.

 

[Gary H NC]

Re: Is EP 90, GL-4 Okay To Use In A 1987 Cobra Outdrive?

Drain that old GL-4 oil. Use the Merc oil or go to Napa and they can get CRC Hi-Vis marine gearcase lube.It is stated in the OMC factory service manual that the CRC is the exact replacement lube for the OMC brand.

 

[HT32BSX115]

Re: Is EP 90, GL-4 Okay To Use In A 1987 Cobra Outdrive?

The whole reason that the factory OMC manual states to fill from the middle is to avoid just what you are trying to avoid. You should fill from the middle.

You know, many a Cobra has been destroyed by filling it wrong. I am somewhat at a loss understanding why anyone would not do it the way OMC recommended.

There are a more than a few places out there that think filling it from the bottom until it comes out the "FILL" port, then capping the drain and filling it from the FILL port is OK.

So you're not alone. I still wouldn't do it though based on what the consequences are if you still trap a "bubble".

Your drive may indeed hold 60oz. The "little" ones held 60, the "mediums" held 64 and the 87-89 Dog-Clutch King held 108oz.


If the service manual says to put GL-5 in it, you should drain the GL-4 and put GL-5 in it. I don't think they make it any clearer than that.


Regards,


Rick

 

[DavidW2009]

Re: Is EP 90, GL-4 Okay To Use In A 1987 Cobra Outdrive?

Gary, Rick,

Thanks for the feedback. I plan on using GL-5 before I go to the water, which probably at least a year, to never.....

(The EP 90 GL-4 does have a marine application, according to the Clymer's Chrysler manual. But again, I will put GL-5 in it before splashing the boat.)

I am going to run some more tests on the drive on the muffs. I don't want to spend $40 for GL-5 only to find the outdrive is bad in some way.

I'll drain some of that lube out and bring the level back down to the fill indicator ring.
64 ounces is too much.

 

[DavidW2009]

Re: Is EP 90, GL-4 Okay To Use In A 1987 Cobra Outdrive?

The local Advance Auto store has Coastal 80w-90 GL-5 for $4.39 per quart. This is way cheaper than other brands that were $10-12 per quart.

Is Coastal a good product or is it "you get what you pay for" thing? Is Coastal adequate for an OMC lower end?