Combines Overheating hydro oil in R62

Bluebeard, You mention that you have blown out oil cooler. Have you taken the hyd. oil cooler off of engine and actually power washed cooler. Over several years of use you will get a build up of material in cooler that only a power washer will remove by getting material wet and letting go of oil cooler fins. You also mention 68 grade oilIJ This machine should be using Dex II or III. Another item to check would be coolong fan dimension on engine. Service manual will give you these figures to compare yours to.If excessively worn it will not produce enough air to keep everything cool. I would not rule out hydro but other common things should be checked first and you can also have pressures checked on hydro system. As oil warms up to overheating you are definitely going to affect operation of all hydraulic related items. Hope you find your problem, Hyper Harvest II

Hyper, Sorry, I forgot to mention that we had replaced the fan two seasons ago. The large hydro oil cooler I have lifted off the engine and have visually checked that there are no passages blocked in the core - looks very clean to me, no build up at all on it. I attended a Gleaner clinic in '03 and they recommended changing from Dexron to Agco Hydraulic Oil or equivilent which is a 68 grade. Australian conditions I guess. Also said to have pressures in hydro checked every 500 hours. local dealer said that checking pressures not feasable on our model machine. I am guessing that when hydro is only half way forward, there is a good flow bypassing through the cooler, push right forward and all the flow is to the hydro motor thus giving me the problem. Has me a little stumped what can be causing the problem other than a great deal of leakage past the pistons in the hydro motor. Any more suggestions most welcome. Bluebeard.

With out actually being there to do some pressure checks I would think there is a high pressure relief valve letting some oil bleed by and heating oil. If memory serves me right there is a forward high press. relief and rearward high press. relief valve and they are identical. I swapped these on one machine to determine if that was the problem. We have a really good hydro repair facility here in the midwest that is really good with troubleshooting. They may be worth giving a call to and describing your problem. Make sure you have the numbers off of your hydro tag so they know which Sunstrand hydro you have. (Hydro Service Inc.515-388-4096 and ask for larry or Dan) Reguards, Hyper Harvest II

Besides the other suggestions hear I would check out cooler bypass valve. Follow the low pressure line back from hydro (large hose clamped line). You will find a brass colored inline valve. This is to hold 30 or 50PSI which will cause oil to travel threw cooler in another line rather than go straight to tank when oil has warmed up some. Might be able to just feel line to cooler and line that goes straight to tank if it is bothering that much. line with valve should stay cooler for it shouldn't have much flow going threw it. Other wise just remove it to have it pressure tested. Good luck