Hello all, read a lot on this forum over the years but finally joined and reaching out for some advice. I have read all the threads I can fin on this issue and this has helped me narrow down my theory. I have a cat 330 BL ser# 8TR00589. The machine has worked fine until recently. The hydraulics are overheating while engine temp remains normal. I have pressure washed the cores and they are clean. Fan belt is tight and everything seems to be normal on the cooling side. I did recently replace the Hydraulic filter. I cant say if this problem started immediately after or shortly after but after for sure. It overheats within 1.5 hrs of work. After I reach 7-8 bars on the temp indicator function speed decays. I suspect a restriction. I ran it today at WOT for a test. am attaching the results of my temp measurements at various points. Basically I just traveled back and forth and did "push ups" with the boom & swinging slowly back and forth 180 degrees. Nothing heavy b/c all the compartment doors are open. Every time the temp indicator rose a bar I took readings. The locations I checked were Tank (right beside the sensor), pump housing at each pump, filter housing at the bypass valve location, pilot filter. On the other side I checked the 4 tubes off of the cooler bypass valve. I refer to them as cooler inlet,outlet, return from main valve body and return to filter. I am attaching my results i put in a spread sheet. I realized I missed a couple but should be good enough to see a pattern. It seems to me that there is not enough moving through the cooler. That leads me to believe I need to inspect the bypass valve. It also seems that the filter housing seems to be generating a lot of heat initially? My questions are: does the entire block and plumbing have to be removed to get to the cooler bypass valve or can it be accessed through the plug on top? Does the pilot oil temp normally run higher than the rest? Could I have installed the filter improperly. I have a tech manual and followed the procedure I thought. (I did remove the canister first) Of course if anyone has any other ideas or suggestions I am all ears. thanks !!
Nothing seems to be attached. Maybe the wrong format for this forum? Some forums only take .jpgs. Might have to convert your document to jpg?
i accidentally prematurely posted. Story of my life. Edited and re-posted Let me know if still not showing. I checked on a different device and I can see the attachments.
All came through...looks good. We'll let the folks who know stuff parse it out. I've got a CAT 320C so I have an interest in what you find out.
Well no one chimed in but I thought I would share anyway, should it help with anyone else in the future. Turned out to be the slow return check valve. Came loseand plugged the return line to the cooler bypass valve. Eventually the restriction broke the valve and sent the pieces downstream where it lodged in a bend just past the cooler bypass in the inlet of the actual cooler. Still missing a piece. Assuming it is in the cooler core.
Wow.
Regarding the inspection of the cooling bypass valve, this valve is usually used to regulate whether the oil passes through the cooler. If the bypass valve is stuck or faulty, the oil may circulate directly without passing through the cooler, causing the temperature to rise. Try to check whether this valve is working properly through the plug above ?
Thank you, but that post was a couple months ago when I was first trying to figure out the problem. Many many hours later I discovered it was the slow return check valve that had failed and plugged the return line. With respect to the cooler bypass valve, I discovered you actually have to take the block apart to access that valve. I believe the plug was only for machining purposes.