Cat 988B heating issue

[kshansen]

Is this your tank..?
View attachment 213279

The tank does not have a breather.
Look at the section A-A in the illustration. That is a relief valve to prevent the tank pressurizing excessively. In your 988B the implement pump suction is above the oil level in the tank so the design is for it to pressurize once the oil gets hot. This assists with oil flow into the implement pump suction side. Provided nothing is stuck in that relief valve you should be fine. Strictly speaking you should only unscrew the tank cap when the oil is cold.

Not to argue here but I'm thinking that A-A illustration is the oil filter cover and the springs are, one to clamp the filter in place and the other is the by-pass valve for the filter. If I'm not mistaken the pressure relieve valve for the tank is actually the item #5 in that drawing.

 

[kshansen]

Isn't the relief valve for the tank the what they sometime call the breaker? Or in this case just simply "VALVE-BREAKER RELIEF"
Item #29 in this picture of a
another S/N range 988B?

 

[John C.]

That's it.

 

[Nige]

You're right Ken. The breaker relief valve functions as a relief valve when the pressure gets too high and as a "vacuum reliever" if the pressure in the tank gets to the point where it wants to suck air in from outside. It's designed to relieve at 20+/-3psi and suck at 0.3+/-0.15psi of vacuum.

Suggest to pull it off and see if it the vacuum side opens when you suck on the threaded end. If it does at least you know the internal mechanism in it is moving and I guess from that test you could assume that it's relieving correctly.

 

[Nige]

Thinking about it you could test it if you were so inclined by rigging up a regulated air supply from your air compressor. Remove the breaker valve and hook the air supply up to the threaded end of the valve that screws into the hydraulic tank. Crank up the regulator slowly and see what pressure is on the gauge when the valve finally pops off. DON'T go above the maximum specified pressure + tolerance, in other words 23psi. If it doesn't blow off before that, it's fcuked. Get another one.

 

[ajginger]

Just an update on this ......

Put the new thermostats in, new fan belts, new cat coolant, re- sealed both the lift rams, drained the transmission, engine & hydraulics & refilled with new oil.
( ouch.... $$ )

Then put her to work building a new road, through the property, clearing about 7 kms of fencelines, then building a new dam wall across a small rock gorge so the cattle/native animals have access to water in country that has remained waterless till now. Also put about 10 hrs into building a large earth tank.

The old 988B ran well and temps stayed within the green on the coolant guage.

Here is a video of her working the dam project.

 

[Birken Vogt]

I'd rather hear the machine....the sound is as much a part of the job as the visual

 

[kshansen]

I'd rather hear the machine....the sound is as much a part of the job as the visual

Yes on the sound, only thing worse would be if this was a 12V-71 Detroit and he put that music on to block the Buzzin' Dozen Music! Not that a 3408 running hard wouldn't sound good! Heck I'd love to hear a D399 genset going through the passes of a load test!

 

[Nige]

Just an update on this ......

Put the new thermostats in, new fan belts, new cat coolant, re- sealed both the lift rams, drained the transmission, engine & hydraulics & refilled with new oil.
( ouch.... $$ )

Welcome to the world of running Big Yellow Iron

Another vote to get rid of the music..........
On the other hand I'm glad to hear that you finally seem to be getting on top of the issues with the machine.

 

[ajginger]

Haha..... should have gone with gut feeling that you guys have diesel running through your veins & would want the authentic version with all the engine noise. ( will upload that as well for you )

One issue I do still have is that I can't get the new ' converter oil ' temp guage to work properly. I think it is the sender unit but cant locate the exact position.
I would appreatiate it greatly if anyone could point me to where it is located.

 

[kshansen]

One issue I do still have is that I can't get the new ' converter oil ' temp guage to work properly. I think it is the sender unit but cant locate the exact position.
I would appreciate it greatly if anyone could point me to where it is located.

Well hard to find one easy to see picture! It is mounted in a valve on rear of converter and has a large steel line going back to the oil cooler.
Hope these pictures help!
This above is the best picture of the valve, arrow point to the temp sensor.

Here is a picture out of prts book showing the two steel lines heading to the oil cooler to the left of drawing.

And this last one shows the cutaway of the valve itself. Arrow shows where steel line connects. For size comparison the bolts on either end are 3/8 inch with 9/16 heads. The temp sender would be just below the plug marked #1, someone cut the boss off for the picture!



And just because I know you were going to ask here is the parts book section showing the sender. Note that in the list item #10 is for torque converter temp and guess what item #3 is for water temperature. Notice something about the two of them??????

Now I'm just wonder when someone will ask about item #9?

 

[DB2]

I’ll bite. What does that solenoid do Ken ?

 

[ajginger]

Hey thanks for that Kshansen......I was looking all over the front of the converter and the transmission housing.

I thought there would be an obvious wire harness to follow to it but it seems to be hidden out of obvious site.

 

[kshansen]

I’ll bite. What does that solenoid do Ken ?

Well that converter is a "variable rate converter" and the solenoid is so you can leave it set in the lower torque position and when you need more torque you can just work the switch on the control lever to get max torque then click switch back off to go to the lower setting.

I'll see if I can find the "official" description on sis!

 

[Nige]

Well that converter is a "variable rate converter" and the solenoid is so you can leave it set in the lower torque position and when you need more torque you can just work the switch on the control lever to get max torque then click switch back off to go to the lower setting.

I'll see if I can find the "official" description on sis!

Variable Capacity Torque Converter (VCTC)..?

 

[kshansen]

Well Cat decided to spread the description over four files!

Attaching them here:

 

[kshansen]

Variable Capacity Torque Converter (VCTC)..?

Yep I stand corrected VCTC is the "official designation!"

And the early ones from the 87A 988 and early 988B's did tend to give some problems till they went from six to nine blots holding them together inside. Did many of those upgrades back then.

If any one wants the full "Systems Operation" on that convertor it is about a 15 page PDF that I just happen to have saved!

 

[ajginger]

Heck you guys are helpfull........ I had been going to research where the vctc solenoid is located so I can get the switch operating again ( nothing happens when you hit the switch ).

Question : Would the solenoid be the only cause for the switch not working ?
Or would there be a couple of things to check first ?

Kshansen, is there a way that could I get that document off you please ?

 

[ajginger]

Here is the version of the video that has no music as promised.

 

[kshansen]

Question : Would the solenoid be the only cause for the switch not working ?
Or would there be a couple of things to check first ?

Well first thing I liked to do to test that system was to put the control lever for the convertor in the "Minimum Torque" position and have the switch in the off position. Not sure if your machine has the rocker switch on the bucket control or the floor mounted switch.

Then either stick bucket into a stone pile or apply the right brake pedal and do a stall test, give it full throttle. While doing this just work the switch on and off. If the solenoid and wiring is working you should have a good indication of the engine coming under more load.

There should be a light on the dash that indicates when switch is in on position also.

Guess I need to do a bit more research on your machine's wiring, yours is the 50W03844 S/N right?