Evening, We have a 325D ( SCR serial prefix with 4700 hours )that is overheating both engine and hydraulics, we have blown out with shop air the hydraulic cooler and radiator and then washed it with light pressure clean the core it is now imactulatly clean. Did not seem to make much of a difference, was wondering if any one else has experienced any common faults with this model, we can hammer and pulverize concerte all day and will not over heat but as soon as we're digging, loading scraping concrete off the top of dirt (raking) it really heats up both. Was wondering if they have viscous fan hubs that give some grief? Any advice would be super, Thanks
Did you actually separate the hydraulic oil cooler from the radiator in order to clean them..? AFAIK it's impossible to completely clean the radiator with the cooler in place. You have to remove either the rad or the cooler (or the complete package and split it once it's out) in order to completely clean them. Is this something that has come up all of a sudden or has it been developing over time..? Do you have access to an infra-red temp gun..? If so when it's overheating shoot the temperature of the hose going from the thermostat housing into the top of the radiator and also the hose from the bottom of the radiator back to the engine. Post back here giving the temperature difference. No fan clutch as far as I can see, simply a direct-drive fan via a serpentine belt. There are however 2 different cooling arrangements, "normal" and high ambient temperature. I wonder which one you have..?
Check the relief pressures on all digging functions and also the main relief, when you use hammer and pulverizer you don't hit max pressures with any function but when digging you could have a problem with a relief setting being to low causing more heat being created when oil is bypassing the faulty relief.
Check the air filter, a dirty air filter will cause overheating under a heavy load.
Does the 325 have an electric fan clutch like my 320dl? You should see a wire going down the front of the fan if you look through the cowl.
Unless it has an attachment fan clutch, no. Standard is direct drive.
Check your book for optional fan Nige, recall one that failed that way, might have been a 320??? If the fan drive is good unplugging it will speed up fan. If it has one it can be programed. breaking will not over heat due to low power setting for that tool. Later Bob
Post a serial number and these guys can look up the configuration that the machine was sold with. As I recall high ambient cooling in those machines has a separate cooler behind the cab and a hydraulic driven cooling fan. I don't recall ever noticing a fan clutch on an excavator. From what I have seen, Nige has the most probable solution of pulling the coolers apart and pulling the junk out of between them.
Check fan belts and pulleys for tension and wear.
The high ambient cooling package option does have an electricaly controled viscous coupling. I've seen at least three in Aus. As mentioned above, look for a wire coming from the front of the fan hub. If you see that wire then......... The bad news is that the early ones fail, first by not spinning fast enough and then, if you leave it too long, the fan will fall off and cause carnage in the radiator cowling. The goood news is there is a service letter to replace the faulty coupling. It expires in July this year. I suggest you phone your dealer and ask him to have a look at it. If the viscous coupling is faulty, you should be able to have it repaired at a much reduced cost. As the machine has 4700hrs on it, you will probably have to pay 50% of the labour, and the travel charge, but talk to your dealer about it. (The service letter is PS52059)
Evening, Thank you all so much for your help, went back to cat with the service letter, they are going to fit new fan hub, due to the hours and the age of machine they will cover 1/2 the labour costs and 1/2 the cost of a complete fan hub ($1300), the product support rep did mention issues with other machines overheating and in some cases slippage of the main belt on the fan hub. This slippage cannot be heard only traced on et by desired fan speed and actual fan speed, they have seen this before and by leaning on the tensioner while operating fan speed increases, thus requiring new tensioner and belt, and ensuring all pulleys are cleaned out with wire brush to allow belt to grip deep in the pulley, we will have all this completed soon and will let you know the outcome, hope this helps any one else in the future, Cheers