John Deere 80 Lubrication Questions

I'm the guy with the 80 and the cracked frame. (A different post). I got my manual a few days ago, got it read, and wanted to see if this was a typo or truth. It says the Diesel engine is supposed to use 20W oil? Operating range of 0 -95 F. If colder than 0, use 10 W. That just seems crazy. I could see it for the Pony, but that just seems really thin for the main engine. I have a 70D and read and read and read a long post or two on what guys were using in their diesels for that engine and the general consensus was Rotella 15w-40. Don't see why that wouldn't work for the 80's main engine as well unless it just has much tighter tolerances??

Question #2. Was looking over the lube chart in the manual which was pretty straightforward, but the fan shaft is puzzling me. It's in a casting that is mounted down from the top radiator housing and holds the fan. No grease zerk, no bearing or bushing it appears, and it says zero about lubing it in the manual. I can't see how a steel shaft spinning in a dry cast iron housing would last. I am going to oil it for sure, but it just seems odd. Going to try and include a photo. Thanks.

I wouldn't hesitate to use 15-40 in the main engine.

Only possible issue would be if it has sat a LONG time and has old oil and lots of sludge in the crankcase.

The fan uses a "waterpump bearing", typically a sealed, unitized ball bearing, roller bearing, and shaft.

<img src = "http://www.gmb.jp/assets/templates/palette-en/img/product/bearing/water_pump_bearing_img01.jpg">

There is a free parts book on the JD web site.

If it's a sealed bearing and no zerk, then it must work fine the way it is. I did download the parts book in pdf onto my computer last week. Have done that on all my tractors and it's very helpful. Just my 2 cents, but I think everyone should always have an owners manual and an I&T manual for everything you've got. They're easy to find on Ebay. The schematic for the fan housing showed "bearing 8515R" but didn't show much of an exploded view (like you provided above-thanks) so figured if it was a bearing, it would have a oil cap or grease zerk, but apparently not.

As for the oil, I'm going to definitely flush the crankcase out, put new oil and filter in it and run it for a while and drop that oil & filter and put fresh in. Oil is very cheap insurance. 15w-40 is what I'm thinking as well. 10w or 20w just seems too thin.

The lighter weight oils were what Deere specified. I know, it seems too light. Keep in mind however, the crankcase on these holds a good amount (more than say a 4020), and there is no turbo making heat, etc.

I had a very experienced Deere Mechanic tell me once, "I've seen far more engines wrecked from too thick an oil than too thin." Too thick means poor lube at cold starts.