Hydro Oil - M1 15W-50, VR1 20W-50 or GTX Classic 20W-50

[Brice]

I'm going to do a fluid change in my ZT-3100s before mowing season. I had planned on Mobil 1 15W-50 for $30/5qt, but I noticed Castrol GTX Classic 20W-50 on clearance for $13/5qt. VR1 20W50 has a stout add pack for about $35/5qt. I just used plain old SuperTech 20W50 last time before I put much thought into it.

Which would you go with? I don't mow terribly much but want this zero turn to last.

A couple recent VOAs on the Mobil and VR1 below. I couldn't find anything on the GTX Classic.

 

[repairman54]

It's not so much the oil but the regular changing of it for long life.
Getting the old oil out before it's worn out is the main thing. I like full synthetics for extra ''cushion'' in case other things delay the routine.
On here we have a habit of picking the fly poop out of the pepper.

 

[Cujet]

Use the M1. It has a proven track record in this application.

 

[Brice]

Thanks guys. I had settled on M1 but my mind started to wander. I'll stick to the plan.

 

[fantastic]

20w-50 is commonly cited for commercial small engines. Even harley davidson recommend this weight because of their air cooled bikes. 20w-50 is going to have slightly less viscosity improvers which would mean 20w50 could potentially be more shear stable.

But if you want to make sure it lasts why not stick with the slightly thicker 20w. I vote 20w-50 but it's your call & the other weight should work just fine too.

The price is right too.

 

[Drew7a]

The 15w-50 does well on the ZTR transaxles.

I have used both 20w-50 and 15w-50 and preffer the 15w-50 less whinning when cold.

 

[Brice]

20w-50 is commonly cited for commercial small engines. Even harley davidson recommend this weight because of their air cooled bikes. 20w-50 is going to have slightly less viscosity improvers which would mean 20w50 could potentially be more shear stable.

But if you want to make sure it lasts why not stick with the slightly thicker 20w. I vote 20w-50 but it's your call & the other weight should work just fine too.

The price is right too.

Synthetic vs conventional base stocks. Plus lots of anecdotal evidence of success in transaxles with the Mobil 1.

 

[Paul B]

Did my hydro on my Husqvarna at 50 hours. Factory fill was a standard 10w30 grade. Removing the axle wasn't really that hard. Cleaned the unit spic n span before I did any oil drain. Let it drain for a couple hours and rotated it to make sure all out. I elected to run 15w50 Mobil One. The magnet was clean with no metallic fuzzies. After the fill I bench bled the system to rid any air pockets and rechecked the proper level fill. I'll tell ya, there was a noticeable difference in performance and how quiet it was. Some might think was waste of time and $$$ doing so early but I call it preventative maintenance. Pay little bit now or a WHOLE LOT more later.

 

[fantastic]

Synthetic vs conventional base stocks. Plus lots of anecdotal evidence of success in transaxles with the Mobil 1.

Yes, thinner oils usually are synthetics but needing more VI. Thicker oils closer to range needing less to be synthetic & lesser VI's. Stick with what you feel comfortable with. I'm sure either will suit just fine.

 

[#18FAN]

Dumped the factory fill on my SCAG ZT2800 filled with Amsoil excellent feel and response it’s just another option.
https://amsoilcontent.com/ams/lit/databulletins/g3471.pdf

 

[gman2304]

My 1998 TT K61 has had Mobil1 15w50 since I dumped the factory fill at about 5 years. After 25 years 2 oil changes and around 2,000 hours, it’s still smooth quiet and responsive. I have used the Vr1 20w50 in 3 Harley’s and an excellent choice for air/oil cooled Harley’s, but in this case I would go with the Mobil1.

 

[MParr]

Hydro Gear recommends 20W50. Any quality 20W50 will work. If you want to use a synthetic 20W50 or Mobil 1 15W50, those will work too.