305 cat runs hot after about an hour of digging. I have clean the radiator, cleaned the oil cooler, and clean the AC condenser. I have taken the radiator to the radiator shop and had it cleaned inside. I have replaced the thermostat and the fan belts, and adjusted them. I was talking to the guy the other day that had a 304.5 and he said his fan blew out through the radiator my fan pulls air in through the radiator and over the motor I have looked at several pictures of 305s and it looks like my fan is on in the correct orientation. Do any of you guys have a 305 and does the fan blow out or suck in through the radiator. Any ideas on solving this problem would be greatly appreciated. I have heard people say, that first generation 305s were bad about overheating but when I called the Cat dealership, he said he has never had a problem with them. Any ideas?
To assist in looking up technical information please supply a machine Serial Number. Generally in an excavator the fan sucks air from the engine compartment and blows it out through the louvres in the side panel. Whether this is the case on your 305 I don't know. It would require photos of the fan and knowledge of which way the engine rotated to determine air flow direction. BTW changing the orientation of the fan will NOT change the direction of the air flow. It will just reduce the volume of air flowing. To change the direction of air flow the fan needs to be rotated in the opposite direction.
Just couldn't provide a serial number
Is the foam that is supposed to be around the radiator in place? The shroud should be tightly sealed around the radiator. On older machines the foam seems to disappear. How long have you owned the machine and how long has the operating temperature been an issue? When overheating what are the actual temperatures at the cylinder head and upper and lower radiator outlets via an infrared thermometer?
This..... Loss of air flow because the foam is missing is one of the largest single causes of excavator cooling system overheating.
I no see-um foam in drawing.
If it's a DSA-prefix then need to look under all the different covers in the Frame & Body section. Every one that's anywhere near the radiator has a sponge seal (order by the metre), insulation, or both.
I suppose there is a piece on left of picture.
On my Takeuchi TB53FR, I put on a smaller water pump/ fan pulley. Finally cured it. As for this thread, where's the original poster at?
"high ambient" usually means over 40C or 100F, which is unusual most places. So what temp are you operating in, and what temp is the engine? The temp of the engine, coolant going to the radiator, and coming back from the radiator, all when the engine is as hot as you run it, will give a good clue what's going on.
Serial number is dgt00722
I replaced the foam when I had the radiator out
So, your serial number should have the revised pulley and belt, therefore, the uprated fan may be a solution, IF, all the insulation surrounding the radiator and cooler is still in place and the cooling fins are all clean.
Serial number is dgt00722 and thanks for the fan tip I was thinking I could turn it around and it would blow the other way, you saved me a lot of working trying to reverse it.
Ok thanks a lot for the info, the insulation has been replaced and the radiator has been to the radiator shop for a cleaning.
From all the above, especially since you have had the radiator to a shop, it would appear that the uprated fan spider and all the associated parts as HMC mentioned above is probably the solution. According to the Service Magazine (attached) it applies to your Serial Number.
Do not know if this applies to your machine but I recently read of a fan system that has a reversal purge option... My words there. It can cycle and and flow in either direction based upon either a pre-programmed cycle or a manual selection.
Not a chance on this one, as the fan is mechanically driven by the engine. Reversing option features only exist on hydraulically driven fans. Dozens may have reversible blades on their fan, but, they have to be manually turned.
Has anyone had success by replacing the fan
There are so few of that model around that you are unlikely to get an answer to that question, especially for a model that was originally manufactured almost 20 years ago. All I can say is that the new fan has 10 blades compared to the 7 of the original, so it should flow significantly more air.
What is the history of the problem? I am always a little wary of blaming something that can't fail, in this case a fan, that worked fine for the last 20 years.
Bought the used 305 from cat dealer had 5500 hours on it they had just installed new engine. Ran it for Personal use for about a year didn’t use much. Then started a business and started using it considerably more, that is when it showed its overheating problems. It will get hot even in cool weather just takes a little longer if you disengage the hydraulics and keep full throttle it will cool down but as soon as you start using it will heat right back up. It takes a while around a hour to heat up when it has been first started for the day but after it has been run it will go from normal operating range to hot in about 15 minutes. I can load a dump truck with dirt before it gets hot but that is about it.
Interesting, sounds as though the problem goes back to the rebuild. Unless the engine was over heated and rebuilt and the underlying cause not addressed. Which of course could never happen at a Cat dealer . . . I would think that inferior fan would not cause issues in cool weather, but would allow overheating during sustained use in hot weather, say over 80* . . . Just a thought? Are the grates in the belly pan clear? The fan needs to pull air through the radiator, but the air needs to come from somewhere and needs somewhere to go. What is the condition of the radiator hoses? In my opinion any rubber hose more than about 15 years old is suspect. Could there be internal failure? Internal hose failure is pretty much invisible from the outside. There really needs to be some thorough analysis of the actual temperatures of the machine when it is running hot. Do you have an infrared thermometer?
Hey Roger, it could be one of the following issues, check one by one carefully. 1- I think it could be a a faulty hydraulic bypass valve. so theres a valve that bypasses the hydraulic fluid to tank instead via the hydraulic cooler. Check if the hydraulic tank is getting hot and use a IR thermometer to check the temps of the piping going to the hydraulic cooler, out of the hydraulic cooler, the cooler and the tank. This could be the reason for the issue. It could be the valve is stuck open halfway. You could just take it out and jam it temporarily to force fluid through the cooler (so warm up time will be affected) but if that eliminates the problem you can just fix it cheap. 2- Could be a faulty master relief valve, although if this is the case the hydraulics tend to be a bit slow.
I forgot to say, so when you check the temps periodically when you use the machine, you will see the tank temp go up compared to the piping to the cooler. Also the cooler out temp will be lower as the cooler is doing its job, just that the majority of the hot hydraulic oil is going direct to the tank as the bypass has failed to close once the hydraulic oil has come up to temp. same logic as an engine thermostat valve. what we used to do as a dirty fix was to jam some coins on the spring inside this valve and jam it shut until it could be replaced or fixed, usually since this was in Sri Lanka which was a tropical climate we just jammed it shut as the warm up was not really an issue due to lack of winters!
The belly pan grates are I have even taken one off to allow more air to exit, I will check the radiator hoses. I have checked the temps with a gun and it seems the radiator has a temp drop from inlet to outlet but I will check again it has been a while. Thx
I think you could be on to something it seems to be the hydraulic oil is what is heating up the system. When it gets hot I disengage the hydraulics and leave the engine running full throttle and the temp gauge starts coming down but as soon as I put hydraulics back in gear the temp immediately goes back up before I even start using machine. It like when I stop hydraulic flow it cools off what is in the cooler then the engine radiator can cool down but as soon as I start hyd flow it moves cool hyd fluid out of oil cooler and puts hot hyd fluid back in it and water temp goes back up again immediately. I feel the hyd oil cooler is getting too hot and putting off so much heat that the radiator is only getting hot air and can’t cool the engine. So if i understand you the hydraulic oil is partially bypassing the cooler allowing it to get hotter and hotter till the oil cooler can’t cool it. If I am not understanding you would you please explain it so I can.
yes exactly. you found the culprit!
small valve attached to a T from the return from the main control valve going to tank and cooler.
You need to know this, not feel it. Use the temp gun and get some hydraulic temperature numbers up here. Tank temperatures and cooler temperatures. Don't take the temps off of rubber hoses. It appears that your machine has stacked coolers from the diagrams that Hymcall posted, which could make hydraulic oil temps very relevant to this discussion. The later 305 C models have side by side coolers.
Yes the coolers are stacked I have always suspected that the hydraulic cooler is what is driving the water temp up. Also the plastic on each side of the seat below the arm rest get so hot it burns my legs when wearing shorts and the AC can’t keep up. im not sure but I suspect that the joysticks have hyd oil running to them like my old skid steer, not like my newer skid steer which is electronically controlled. As I think back heat in the cab has gotten worse over time. Does anyone know where this valve is located on a 305.
Get the facts with your temp gun before you start messing with the hydraulics . . .
I will be running it next wk I will take my temp gun with me, I can’t really tell anything unless I am working it.
A couple thoughts; The hydraulics are normally too hot to touch when the machine is hot and working. The pilot circuit may not be as hot, but numbers are necessary. The hydraulics don't "disengage". When the engine is running, the pump is turning and oil is flowing. When you stop working it is reducing the load, and therefore the temperatures drop. I have a 305c, I find that the air conditioner struggles when it is hot out. There is a lot of heat coming up through the seat, as our are essentially sitting on the engine. Mine is older and the insulation isn't in the greatest shape, but I have my doubts that the AC was ever very effective.
Something changes on the hydraulics when the lever that engages the hydraulics is pushed down because after the engine gets hot I can quit working the machine but the temp gauge doesn’t fall but as soon as I disengage the hyd lever the temp gauge starts falling but when I put the hyd lever back down it immediately starts raising the water temp Even when not working the excavator i guess the pump is turning all the time but it seems oil quits flowing through the cooler when I lift the hyd lever and the oil that is in the oil cooler cools then the water temp starts to drop but when i put hyd lever back down a new batch of oil runs through the cooler and once again heats up the radiator. You are right about the AC it is barely sufficient even when the engine is cool. I know there is heat coming through the floor but I feel the hyd hoses that run to the joysticks is what is heating up the consoles the joysticks are mounted on. I am assuming the joysticks are mechanical like my 226b was. My 259d doesn’t have hyd lines in the cab it is all electronically operated.
Roger, are the hydraulics going to the levers getting hot? I.E the joysticks etc? Is the the hydraulic tank super hot I mean like if its like scalding hot its too much. you should be able to keep you hand on it. be careful! Better to use the IR gun just in case. do the hydraulics slow down when it gets hot? Is the pump getting fully loaded? Do you have a hydraulic quick coupler or some aux hydraulic line thats been looped. I mean sometimes people connect the high pressure hose to the return line to plug a leak or something silly like that and end up creating a demand for flow and if that return line is directly sent to tank (if its like an aftermarket job) then it could be a reason as well. It could be causing pump to go to full swash and all that unused energy gets converted to heat, cavitation etc and causes the temp to go up.
The joysticks are not hot but the panels on each side of the seat that the joysticks are mounted on get so hot it will burn your legs with shorts on. I don’t notice the hydraulics slowing down when it gets hot but there is a hydraulic thumb on the machine and it seems to work way to fast, when you open it back up after using it it slams against the stick.
ok looks like you have a problem there. The flow to the thumb is probably taken out of the wrong place. It seems like too much flow going to thumb. also check pilot pump pressure and lines for temperature. Could be the pilot pump pressure setting is too high or relief valve problems etc. Check temps on pilot hose from pump and also main pressure hose from main pump and check if one of them is getting too hot too fast. I have a feeling the pilot hose is getting hot very quickly due to some fault there. I think the thumb plumbing may have a problem. Something as silly as a larger size hose running without a relief valve etc. And check return hose if its being sent to tank directly. See if you can plug the thumb high pressure hoses and operate the excavator to see if the temperature issue goes away. that could be an easier way to diagnose the fault. You could get an end cap and plug it and see what happens to temp.
Prepare yourself now with some photos of all the hydraulic plumbing, especially on the boom & stick, because that’s probably the next thing you’ll be asked for.
Ok you are going to need to slow down. I’m a pretty versatile guy when it comes to working on most anything mechanical, i can rebuild hyd cylinders engines and fix about anything, but my knowledge of the hydraulic system is pretty weak, you are going to have to slow and explain a little more in detail when talking about pilot pump pressure, pilot hose p, and pilot pump. I don’t know if a pilot pump is different to a main hyd pump, I think pilot pressure is different system that is used to operate the valves that control the main hyd pressure. but I may even be wrong about that. Any schooling you can give me would be much appreciated. I don’t take my equipment to the cat store to get it worked on I generally find someone that knows something about it then I dive in head first. Sometimes it cost me more to fix it than someone else but I learn something in the process That I can use next time.
Without actual numbers all anybody is doing is guessing. We will be dragging out the parts cannon next . . .
Quick de-rail...I looked for a forum/thread about this question (I would call it "tools" or "test equipment") but nothing jumped out at me. There is lots of mention in this thread of using an IR gun for heat readings. What are the specs y'all recommend for an IR gun? I have seen them on Home Depot for $29 and then some are $299. What specs do I need to look for when I get one? I don't plan to use it a lot so I don't need a "shop grade" unit. Thanks.
I understand that and I will get some numbers and pictures next week when I am using it but in the mean time I need to understand the hyd system a little better. No parts cannon for me
I have a Milwaukee gun but I think most of them are fairly accurate, I wouldnt buy the cheapest thing I could buy but u don’t need to spend a bunch of money on one. I’m just a Milwaukee junkie.
My TB53FR and TB180FR machines are same way. The pilot hoses warm the armrest consoles to the point that you can't hold a hand on them. Unfortunately, perfectly normal. IMHO, the cooling system was poorly engineered, just as it was on my TB53FR. Just because Cat hides behind the "for high ambient", doesn't mean it won't run excessively hot on an 80°F day. Look, its a early generation mini that shows not one, but two revisions, to aid in running cooler. Either put on the noisier fan or change the duty cycles of your work. It's just the nature of the beast.
To tick a box, post a photo of the installed fan and indicate in which direction it rotates - just to eliminate the possibility that it is installed backwards. Remember my earlier post that installing the fan the “wrong way round” will NOT change the direction of the air flow, only reduce it, and with a cooling system that's marginal at best you can’t afford that…..
I have looked at pictures Of other machines and they seemed to be mounted the same way, so I’m assuming it is correct. Don’t think a picture will help cant hardly see through the fan guard.
If I could talked to someone that had installed the other fan and it worked I would do it in a minute. But I hate to do it if I have a hydraulic problem, I would like to make sure that’s not the problem first
You said earlier it had an engine change before you bought it. There is a 50/50 chance that the fan might have been installed backwards during the engine replacement. This is how it's supposed to be installed with the fan belt & pulley for reference.
My fan looks like this one, not mine but can hardly see mine for the guard.
If your fan installation looks like the photo above which way does the engine rotate, clockwise or anti-clockwise.? Another thought. A fan installed backwards can cause a loss of airflow of anything up to 50%. In a marginal cooling situation such as in your model any airflow losses could be the straw that breaks the camel’s back.
I put pic of original fan installed on motor in post #3...first image.
Looking at front of engine it turns clockwise
Yes that is the way mine is orientated
Thanks I will try that I have figured out that I don’t operate it at full throttle it doesn’t get hot.
Don't leave us hanging. If you do ABAB testing, does it still get hot at full throttle? and not when operated at lower throttle? and then again at full throttle? and again not at lower throttle? In what temps, and what RPM are you talking about?
I can run at 3/4 throttle and not overheat, I have bought a 2021 306 so im giving the 305 back to my brother who I had borrowed it from.
Did this problem ever get resolved. I have a 2005 305 Cr same symptoms. New motor from Cat 2 years ago. Problem existed with original motor as well. Very annoying issue. Today was 84 degrees same situation after an hour temp goes to H. Have to stop let idle for 10 min than can go another 1/2 hour then back to Hot. Pusher fan installed on hydraulic cooler also. Does nothing. Problem not present with temps in the 50 degree range.
I think the high water temperature is caused by the mismatch between the engine and the hydraulic pump power or the high load of the hydraulic pump
Going back through all the points made in the 3 pages of the thread what have you checked/ticked off so far.?
No I gave t back to my brother and bought a 306