L345DT getting warm.

Hasnt overheated yet but today I was using the PTO for about 15 minutes straight , 70 degree day, and the temp guage started getting close to the HOT zone.

I noticed that my upper radiator hose was hot and had pressure but my lower was cool and didnt feel like had pressure.

Previous owner replaced radiator due to having a leak and also replaced water pump for unknown reason.

Do I have a potential issue with the thermostat? Lower radiator hose being cool seems like a clue to me.

little update on this.

I visually looked at radiator fins and they look fairly clean to me. The radiator is fairly new, The PO said he got the original one re-cored due to leak.

I was running it for about 10 minutes with PTO engaged driving a hydro pump for my BH. The temp rose a little above the middle towards hot but not on hot yet so I throttled to idle and the needle climbed slightly hotter, still not on H and in the normal range.

At this point I used my IR gun and got 150-175F all around the block and the thermostat housing. The upper rad hose was about 120 and had pressure and the lower rad hose was 90.

Maybe the gauge is just sensitive? It has never made it to HOT level