IceStationZebra
Gold Member
I haven't heard of an oil yet that doesn't get thinner as it heats! Full synthetic generally doesn't thin as much, but that all depends on the VI improvers used in the additive package.
As far as testing your system JJ is on the right path.
1. Check you relief pressure with cold oil. Set it to the high side of the OEM's recommended range and be aware that you might have one relief on the tractor and another one set a little lower on the FEL
2. Heat the oil to 150-170°F.
3. Check when hot. If it is below the recommended range there are three prime suspects. A: a weak spring in a relief valve B: a worn pump and C: worn out hydraulic oil.
If you suspect the oil you could save yourself some time and $ by getting it checked first. You should be able to get it analyzed for about $30. Get the oil warm and thoroughly mixed before you take the sample for best results. If you can't find a lab most CAT deals have an inhouse facility.
The ideal is to compare a sample of new unused oil to the used oil in your tractor. At work I always pull a sample when brand new to get a baseline. But if you don't still have the exact same barrel don't bother sampling new oil because oil is mixed in batches and will vary.
A quick way to warm the oil is to fully stroke a function and hold it over relief with the engine at about 2/3 throttle. Do this 15-20 seconds at relief and then 40 seconds with the lever in neutral. Repeat twice more, then fully cycle all the motions to mix the warm and cold oil. Repeat until the oil in the reservoir (usually your tranmission case) is at least 150°F.
ISZ
