CAT 312 questions, I have a few.

I have a cat 312 that I bought a little over a year ago to use around the farm.
It is a 1994 model and has 5400 hours on it.
I have put about 200 hours on it with not problems so far. NO leaks, runs cool, starts easily, good power, walks true.
I changed the engine oil as soon as I bought it but nothing else.

All the work I have done so far was in cool weather, today was the first day of work in hot July south Georgia weather.

(1) The HYd oil temp got very close to the red line so I shut things down after about 3 hours of work.
What should I look for as the most likely cause of the hyd oil getting hot?

(2) A very small leak sprang forth dripping from the left side belly pan. I removed both of the left side inspection covers to expose all the small hoses that run up to the hand controls and it looks like this leak might be from the left joystick.
I have no idea how to get at the hoses under the arm consoles.
How do I get to where the hoses connect to the joystick?

(3) there is also a small hose that looks like a vacuum hose that is not connected to anything but has a hose couple on the end.
Can anyone tell me what this hose connects to? I could not see anything for it to hook to.

(4) The control pad is faded and I really do not know what all the buttons control.
Can someone clue me in on what these buttons control?

THanks in advance.

Regarding your first issue, try this ....................

https://www.heavyequipmentforums.com/showthread.php?44770-running-hot

#3 where abouts is the suspect vacuum line located? Could it be the aircon Evaparator drain line that someone has attempted to block off?

Hello Southern Man,

It's been a couple of years since I took the left hand console apart on my machine (312 BL), but here's what I recall. There are screws that hold the top of the console to the bottom section. The top includes the whole length of the console with the climate controls and fusebox, etc. There are screws positioned horizontally around the perimeter of the joint (where the upper meets the lower), and there may be a copule of screws in the fusebox also. Take out the screws, and as you lift it up pop the base of the joystick boot out and let it stay on the joystick. Of course, you mayhave to unplug some wires if there is not enough room to lay the upper console to the side. This may or may not be enough to allow you to inspect the joystick connections. If not.....

Next, I remember having to take the little handle off the hydraulic lock out mechanism -- just a couple of other screws I think. There may be a small cover to remove also.

Now, really stretching my memory, I believe near the base of the lower console are plastic or rubber covers that snap in place. Remove them and there are screws that hold the lower console in place. You are just going to have to feel you way around looking for screws that hold it all together.

(4) The control pad is faded and I really do not know what all the buttons control.
Can someone clue me in on what these buttons control?

Send me a pm with your email and I can get you my operators manual

dirt dobber, I tried sending you a pm but the system will not allow me to access your profile page to do that.
mine is abc123email(at)yahoo.com

fsmech:
The small rubber hose is bundeled in with all the hyd lines running up to the joysticks. It runs toward the front of the machine toward the windshield but stops about a foot short of the tractor front. Has a green connector in the end of it.

NIge:
The water is not running hot just the hyd oil.
does that make a difference?

Southern,

Emails sent - had to break it into two sections (7 MB each).

Southern Man said:

NIge:
The water is not running hot just the hyd oil.
does that make a difference?

Click to expand...

Not necessarily. In almost every case a in a hot-running machine the issue is in the radiator/cooler package because the two are sandwiched so close together and it's impossible to clean them thoroughly without removing them. I would suggest doing that as a first step and at the same time change the hydraulic oil and filter(s) if you are either unsure of what's in there and if the previous owner cannot confirm the last change. The recommended change interval is every 1 year for a low-hour machine like yours. The correct hydraulic oil is an SAE 10W (ISO 32) oil.

Southern,

Nige is correct in that you need to make sure the AC coil, oil cooler and radiator are all clean. The good news is on the 312 you don't have to disconnect the lines to gain access. I had to clean mine, and there is enough excess line that I was able to unbolt each component and seperate them enough to thoroughly clean them (I think the AC coil laid completely out of the way....watch your battery posts). You want to wash in the opposite direction of the air flow. To reach the bottom of the radiator, I took a straight piece of 1/2 inch copper pipe, clamped one end in a garden hose, capped the other end, and drilled some small holes (1/8 or so) just above the cap so water would spray perpendicular to the pipe. Use it to reach to the bottom of the radiator and anywhere else that needs a good cleaning.

Southern Man : ….. Welcome to the Forum …… With regards to your 312, I might have the evil twin to yours …… Same YR and close to the same HRS …

Mine had these very same issues as yours ….. fought to find what the cause was, as yours …. everytime the ambient outside air temp went up the machines system temps went Nuts !!! ……

My hyd temps went so nuts that i'm now paying the price …. didn't cook the system, but, ALL of the O-rings (like in the Rotary Manifold) are hard and is bypassing within ……

One of the failures due to excessive heat was the electric throttle positioning motor AND cables melting to a point of seizure …… $$$$$

Long story short !!!! ……if once u'r rads are ASSUMED clean and the temps still go Bionic ….. Guaranteed it will the the Main Radiator …… I wouldn't of believed it if it didn't happen to me !!! …. $$$$$

The rads of the machines Era had a issue with Electrolysis within the radiator …… we sometime call it "water stone" build-up, looks like calcium deposits from the water when you look into thru the rad cap …….. UNTIL I talked in depth with a radiator tech …… He pointed out if this was true of the excess calcium that in one filling there wouldn't be enough parts per million to cause that much blockage inside the rad …… True Enough ! …… SO I ASKED ! …… What is the Cause ???? …….. It is Was the type of Lead used to build these Rads having a reaction to the Anti-Freeze causing the Lead to build this white hard stuff up within the tubes of the Radiator …… You could have the end Caps removed, where they Rod-Out the tubes, BUT no guarantees that there won't be Damage ……

My only solution was to Replace $$$$$ the $$$$$ Radiator $$$$$ …….. Brand New from CAT …… Local shops (including, for us, Vancouver/Edmonton) could NOT build one as cheap or for the cost directly from CAT/Finning ……….. END RESULT was It's fixed and has NOT heated up once in the last 7 yrs since that re/re …….. after attaining the literature from Cat support about these issues of electrolysis it backs-up what happened to me ….. We NOW USE only the polyethylene glycol (red or barney purple crap) Anti-freeze formulated for Diesels only, as what is found from the factory in my Dodge Cummins, Bobcat, and my newer 320CL …… Sometimes they also call it LongLife Antifreeze Coolant ……. As a small note too, VW diesels also have been using this stuff since the late '70s in their cars too …….

Cheers and Good-luck !

Another quick thought about hydraulic oil. SAE15W/40 engine is oil an alternative oil but is not the "preferred" oil. Years ago a lot of users ran engine oil in hydraulics, today not so much as the demands of modern hydraulic systems have increased to a point where IMHO an engine oil can't meet them. Despite that engine oil is still listed as an alternative. You really need to get to the bottom of what oil exactly is in there.

Once the issue of the radiator/cooler being externally clean and the issue of the hydraulic oil/filter condition was out of the way I was thinking about taking the discussion forward to the coolant itself. The next question is - is the radiator core copper/brass or aluminium..? If you can't tell at a quick glance from outside pull the radiator cap off and smell the coolant. Can you smell ammonia..? If you can then guaranteed the radiator has an aluminium core and will require a coolant conditioner for aluminium to be put in the system in addition to the coolant/antifreeze. If you can't smell ammonia it's not a cast-iron guarantee your radiator is copper/brass. What happens is the ammonia smell only occurs while a degradation is taking place in the coolant. Once certain additives in the coolant have been depleted to zero that process will stop and the smell will disappear. I would recommend only using a pre-mixed heavy-duty red-coloured Extended Life Coolant (ELC) for diesel engines that meets ASTM D4985 or D5345. Stay away from anything that only meets ASTM D6210, that stuff is not good enough for a machine cooling system.

Craft, Nigel, and Dirtdobber. Thanks for your help and input.

Today I stopped by and needed to move the machine from the location it was in when I shut it down on Wed.

After it was running for about 10 minutes 2 warning light came on. After getting a peel at the 312b owners book that dirdobber sent it was the Electronic controler light and the monitor panel light. When I started to shut the machine down it kept running even with the key removed. I reinserted the key and switched to the on position and this time the machine shut down.

When it rains it pours.

It will be a few days to a couple weeks till I can get around to it but plans are to.
(1) Change hyd oil and filters.
(2) Remove and clean the radiator and oil cooler, no A/C in my machine.
(3) replace the 2 top fan belts, they are a little frayed.
(4) Flush and replace coolant.

After reading Craft's post I fear that my new problem today may be the electronic throttler cables.

I am still all ears for any input.

And

Thanks everyone.

Do #2 on your list before #1, just in case you have to disconnect any hydraulic lines to remove the cooler for cleaning. It would be a shame to throw new oil away.

I will. Was you recommending using the red coolant no mater what the make up of my rad is?

Whats your opinion on the electrical issue I described?

IMHO irrespective from what material your radiator is made you want to be using the red ELC. The only question is whether or not it will require the additive for aluminium radiators.

Regarding your other issue the people to ask on here are the excavator specialists.

Southern Man said:

I will. Was you recommending using the red coolant no mater what the make up of my rad is?

Whats your opinion on the electrical issue I described?

Click to expand...

Southern Man : ….. Unless you are for sure that your machine is still not ALL original (meaning that the rad has been exchanged to another) the rad WILL be as mine was and as the New one is … Brass/Copper/Lead soldered/welded the core and top & bottom caps on with the lead based solder …….

This happened to me too, as far as not shutting down … check the linkage ball joints at the fuel pump …. they get worn and will Jam up (a stage that happens before they fall apart) …. cheap to fix … the throttle control motor has Nothing to do with shutting down …. there is a elec solenoid with a rod that pushes forward to mechanically shut the fuel going into the pump OFF ….. that can and will, as I said fall apart, the other thing that has happened too, is the wires connected to the solenoid can/ will get loose causing a poor connection (kinda like when the battery terminals get loose) so you have to cycle the key switch a couple times to make connection ….. weird but it happens …..

The symptoms of throttle motor failing is the motor WILL NOT increase or decrease engine RPM, mine drove me nuts because it would work when (under cowl) temps were cooler and once Hot the cables would seize-up ….. you have a Manual throttle override switch under the covers (back of the armrests) 2-switches that 1.) will turn off the Auto part of the stepping motor 2.) a spring loaded switch that you toggle in the direction of up or down RPM ……. At the time mine failed the motor burned out from fighting the seized cables …. $1800 CAD at the time I replaced …

Another thing to CHECK ! …… It's hard to visually see but you can feel …. Engine COLD Preferred …. is my muffler had the bottom drain plug Rot Off causing a lot of soot everywhere under and behind cowl/lid/doors …. we (Finning so called techs and myself) always thought the stainless band clamps or exhaust manifold or ??? but as it turned out the welds rotted off and Pure "HOT" exhaust gasses were under the hood causing even more reason to have extreme temps …….. these are all simple to fix if its the cause and the stepping motor is not damaged from the heat …..

It's worth a check if as a person like me mentions this ….. NO ONE told me leaving me to 2nd guess everything and Costing me BIG $$$$$ in the end ……

As far as the Rad issues I had (anti-freeze type) the info was directed NOT from CAT Techs but from Radiator Journeymen that had been in the business for over 40yrs, again a hard $$$$$ lesson learned ….


Hope my little insight helps save a few Bucks in the end ….. Cheers ….

Craft, Thanks again, I may noy always follow free advise but I will always listen to it. (so long as the BS does not get too deep)

Do you think all of the things happening at the same time had any thing in common or were they just consistences.
The timeline again was.

One day about noon I mounted the machine and was doing light brush clearing, *more walking than digging/pushing/piling.
About 3pm I noticed the oil gauge getting closer to the red than I have ever seen before. 2 bars away from RED.
A warning buzzer sounded for 2-3 seconds and then went off.
I shut the machine down 5 minutes later and the gauge was 1 bar away from red but never entered the red zone and the oil temp warning light never came on.
The next morning I had ran the machine for about 5 minutes when the (listed in the 312b owners book) warning lights #4electronic controller & #5 monitor panel came on. I walked the machine out of the work zone to level ground and then the machine did not want to shut down. IT took a few attempts of cycling the key to get the machine to shut down.

Also on my to do list is installing a new aftermarket muffler, the previous owner had converted the machine to a straight pipe so I will most likely have to buy the mounting hardware and turbo-muffler connector from CAT.
I also plan on replacing the stick to bucket pin and bushings.

Thanks again to everyone.

here is a photo of my unit.

As a comment regarding Craft's radiator issue and the "electrolysis" reaction with anti-freeze that would entirely depend on the type of anti-freeze/coolant being used in the system. Mixing an old-style D6210 anti-freeze with a "modern" D4985/D5345 organic-acid-based ELC would be a recipe for disaster. An issue that's easily solved - all you have to do is have samples of the collant analyzed every once in a while.

A question for Craft - Do you buy your coolant pre-mixed or concentrated and dilute it with water..?

Generally copper/brass radiators assembled with lead solder pose far less issues than their aluminium-cored equivalents, at least in my experience. Aluminium-cored radiators are extremely sensitive to coolants and their additives.

still no photo?????

got it.