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Cat D6H LGP 2 overheating engine (coolant restrictor?)
- Thread starter JAJ
- Start date
Nige
Senior Member
i have no idea. I searched everywhere and could only find that data I posted above. Whether the sender performance between the two mentioned temperatures is linear or something else I'm afraid I have no idea.
Just throwing it out there, but have you considered dropping the coolant and running the machine for a while with cooling system cleaner just to see what comes out of the drain plug.? I would say it's worth a shot.
The sticker will read more accurately on the metal radiator tank than on a rubber hose, the hose is insulating and the surface will be between the coolant temp and the air temp.
Next time, try to determine what voltage the gauges are being supplied with, in older equipment there would sometimes be a voltage stabilizer just for the gauges. I don't know if these gauges do that internally, or if there is still a voltage stabilizer on something like this. I'd check the voltage supplied to the gauges, and then sent to the sensor with the wire disconnected at the sensor, both when you first start, and after a couple hours when they're creeping up.
Next time, try to determine what voltage the gauges are being supplied with, in older equipment there would sometimes be a voltage stabilizer just for the gauges. I don't know if these gauges do that internally, or if there is still a voltage stabilizer on something like this. I'd check the voltage supplied to the gauges, and then sent to the sensor with the wire disconnected at the sensor, both when you first start, and after a couple hours when they're creeping up.
Nige
Senior Member
Maybe someone can interpret better than me how exactly this table should be interpreted. I assume the 312 Ohms is a resistor in series with the sender on the signal side.?
Inspection procedure: The resistance of the sender must fall within the limits shown in chart at indicated bath temperature with sender in a continuous flow bath with series resistance and applied voltage specified in chart. Bath medium shall be U con oil spec. 50-HB-280X with flow controlled to 228.6 to 254.0 mm per second. Power shall be applied for minimum of seven minutes before inspection.
Inspection procedure: The resistance of the sender must fall within the limits shown in chart at indicated bath temperature with sender in a continuous flow bath with series resistance and applied voltage specified in chart. Bath medium shall be U con oil spec. 50-HB-280X with flow controlled to 228.6 to 254.0 mm per second. Power shall be applied for minimum of seven minutes before inspection.
Yes, that's how I would read it. The 312 ohm resistance added in series is supposed to replace the gauge (and voltage stabilizer if there is one) to test the sender under the same operating range as it would be on the machine. The math adds up.
But I'm a jack of all trades, not a cat or instrumentation guy.
But I'm a jack of all trades, not a cat or instrumentation guy.
Nige
Senior Member
There is no voltage stabilizer other than what's inside the alternator.
The gauge power is fed directly from the ACC side of the ignition switch.
The gauge power is fed directly from the ACC side of the ignition switch.
JAJ
Well-Known Member
Thanks heaps for both adding your thoughts
Did some temp testing yesterday with my multimeter temp probe dropped in the top tank of the radiator at different times to compare to the gauge and also the temp stickers. I had been putting the stickers on the steel top hose just above the thermostat housing but I did as Delmer suggested and put some more on the top tank beside the inlet top hose. The steel must be thinner there as the temp stickers read little bit hotter.
So results are
Gauge: Top tank: Sticker:
92. 85. 82 bubble popped
105. 96. 93 bubble popped
109. 99. No change
It seemed to stabilise around 110*C on the gauge working hard. Based on my testing it seemed it was safe so I put it up to second gear for a while to see what would happen. It crept up to 115*c on the gauge and seemed to stabilise. So I let it cool back down as I figured I would have to be close to setting the temp light off…. But it never came on. The day was about 41ish ambient. I’ll post pics of the sticker but it looks like it was about to pop the 104*c bubble. The radiator has done 10.3hrs since being blown out and is due but I think this indicates I’m dealing with a gauge issue not an overheating problem per se.
We had a 49*C ambient day a few days ago and it was reading between 110-112*c then I think, with a cleaner radiator but I was stopping every now and then and letting it cool off for a few minutes.
Would be very interested to hear your thoughts on this data.
Did some temp testing yesterday with my multimeter temp probe dropped in the top tank of the radiator at different times to compare to the gauge and also the temp stickers. I had been putting the stickers on the steel top hose just above the thermostat housing but I did as Delmer suggested and put some more on the top tank beside the inlet top hose. The steel must be thinner there as the temp stickers read little bit hotter.
So results are
Gauge: Top tank: Sticker:
92. 85. 82 bubble popped
105. 96. 93 bubble popped
109. 99. No change
It seemed to stabilise around 110*C on the gauge working hard. Based on my testing it seemed it was safe so I put it up to second gear for a while to see what would happen. It crept up to 115*c on the gauge and seemed to stabilise. So I let it cool back down as I figured I would have to be close to setting the temp light off…. But it never came on. The day was about 41ish ambient. I’ll post pics of the sticker but it looks like it was about to pop the 104*c bubble. The radiator has done 10.3hrs since being blown out and is due but I think this indicates I’m dealing with a gauge issue not an overheating problem per se.
We had a 49*C ambient day a few days ago and it was reading between 110-112*c then I think, with a cleaner radiator but I was stopping every now and then and letting it cool off for a few minutes.
Would be very interested to hear your thoughts on this data.
JAJ
Well-Known Member
I checked the voltage at the gauge but I missed the bit about the sensor sorry.
After warm up at first start, full revs 27.36V
When hot 27.6V (was varying between 27.5-.6)
Nige
Senior Member
JAJ
Well-Known Member
I was going to run some cleaner/flush through the system before but I thought I had it sorted when I found the earth dramas and the client wanted me to hurry up and get the last few days done on his job so thought I’d test it again and see.
I have a manual gauge and some Cummins Restore and Restore Plus coming on the mail today.
I think I could have a bit of build up in the radiator that if cleaner out will certainly make it better again.
I also have another coolant temp switch ordered. I thought it would be good to make sure there is a new one fitted in this situation. The one in there looks good but just to be sure. I also ordered a hydraulic oil temp switch that activates at 102*c and was going to add that on a seperate light to give an early warning that things were getting hot… but the manual gauge should be better anyway I think???
JAJ
Well-Known Member
I was typing when you replied. Thanks for the input.
Have the cleaner coming today… I want to fit the manual gauge first and test today to see what it reads so I have a base line with it before the cleaner goes in. Apparently the Cummins Restore Plus will remove rust and scale so I might wait till I get the machine done on this job and home incase I have to remove coolers if they get blocked. The Restore one removes other deposits so I might run it first then progress to the nuclear option perhaps???
Re the voltage… it seemed high. Do you think that could be the cause with the gauge reading high?
Nige
Senior Member
I wouldn't think so. To get a charge into the batteries of a 24v system you need to generate far more than 24v to force the electrons back in the opposite direction.......
Usually High system Voltage alarms on electronic machines come on around 30v and VERY HIGH warnings at 32v. I wouldn't think 27.6v is high at all.
Last edited:
JAJ
Well-Known Member
Yes for charging I thought it was fine but I thought perhaps it might be high for the gauge… thanks for clarifying.
I miss read you response too, missed the “wouldn’t” in the “wouldn’t think”
Ah well I hope this manual gauge will fit and I’ll report back this evening with more data
Thanks again.
JAJ
Well-Known Member
Another update
Did the cleaning flush treatment today.
Fitted the manual gauge the day before.
The manual gauge confirmed that the electric gauge is out a lot. It looks to be between about 7-10*C lower on the manual gauge, which backs up the other tests.
It was still running hotter than it should be at around 103-4*C and the electric gauge reading just over 110*C.
The radiator did need a proper blow out but, at one stage I had to free run 10minutes to the next line in second gear and it still went up from 90 (after cooling it down) up to 105*c. It was 44 ambient but I thought this was pretty telling that it needed a flush.
After this and knowing I had a gauge I felt I could trust I worked in second gear to see if the light would come one. It did and read about 112*C on the manual and just off 120*C on the electric. This was a bit out of spec I think? Cooled it back off and then worked in first gear again.
Today drained coolant put in the first alkaline chemical and worked it for 2hrs and then drained and flushed it 5 times I think it was, till it came clean then refilled with a weak mix of green coolant to test it with. The flushes weren’t a really dirty brown but a milky looking sort of colour with a green coolant tinge. A bit of sediment in the chemical run and a little bit in the first clean flush but bugger all if any after that. I think it made a difference and well worth doing but won’t know exactly how much difference till tomorrow. Depending on how it goes now, I might wait till it gets home and then run the acid based cleaner as well. I want to flush and swap over to Cat ELI as soon as it gets home, think that will be a good move??
I can post pics of the coolant and flush samples if anyone wants to see them for diagnoses purposes?
Did the cleaning flush treatment today.
Fitted the manual gauge the day before.
The manual gauge confirmed that the electric gauge is out a lot. It looks to be between about 7-10*C lower on the manual gauge, which backs up the other tests.
It was still running hotter than it should be at around 103-4*C and the electric gauge reading just over 110*C.
The radiator did need a proper blow out but, at one stage I had to free run 10minutes to the next line in second gear and it still went up from 90 (after cooling it down) up to 105*c. It was 44 ambient but I thought this was pretty telling that it needed a flush.
After this and knowing I had a gauge I felt I could trust I worked in second gear to see if the light would come one. It did and read about 112*C on the manual and just off 120*C on the electric. This was a bit out of spec I think? Cooled it back off and then worked in first gear again.
Today drained coolant put in the first alkaline chemical and worked it for 2hrs and then drained and flushed it 5 times I think it was, till it came clean then refilled with a weak mix of green coolant to test it with. The flushes weren’t a really dirty brown but a milky looking sort of colour with a green coolant tinge. A bit of sediment in the chemical run and a little bit in the first clean flush but bugger all if any after that. I think it made a difference and well worth doing but won’t know exactly how much difference till tomorrow. Depending on how it goes now, I might wait till it gets home and then run the acid based cleaner as well. I want to flush and swap over to Cat ELI as soon as it gets home, think that will be a good move??
I can post pics of the coolant and flush samples if anyone wants to see them for diagnoses purposes?
JAJ
Well-Known Member
Got to test it out today. Seemed to take a lot longer to heat up and then stayed around 92-95*C on the manual gauge until the trans temp finally met up with it. That took a lot longer than normal too, but once it caught up it crept up to 100. Comparing the electric gauges the trans and engine temp, the trans still stayed 5-10*C hotter and stabilised. It was only 38*C ambient today which would have helped.
So I think the flush certainly helped but it has me a thinking now that perhaps the trans could be contributing still. I thought I had that sorted but wondering what you guys think?
I blew a hydraulic hose (I think going to the valve on the underside of the main hydraulic pump) and have to remove the belly plate to get access to it. While I’m under there I thought I might pull the scavenger line off the torque converter to check the screen. My idea is the converter might not be draining properly and slowly building up…. not sure if this could cause what I am seeing but thought worth checking.
Any ideas what I should look at next is most welcome!
Also Nige I wanted to pick your brain about transmission oils. The local Cat dealers tell me to only ever run sae30 oil but the book says that for higher temps sae50? What would you recommend?
Any ideas or thoughts most welcome
Thanks for the help guys!!!
So I think the flush certainly helped but it has me a thinking now that perhaps the trans could be contributing still. I thought I had that sorted but wondering what you guys think?
I blew a hydraulic hose (I think going to the valve on the underside of the main hydraulic pump) and have to remove the belly plate to get access to it. While I’m under there I thought I might pull the scavenger line off the torque converter to check the screen. My idea is the converter might not be draining properly and slowly building up…. not sure if this could cause what I am seeing but thought worth checking.
Any ideas what I should look at next is most welcome!
Also Nige I wanted to pick your brain about transmission oils. The local Cat dealers tell me to only ever run sae30 oil but the book says that for higher temps sae50? What would you recommend?
Any ideas or thoughts most welcome
Thanks for the help guys!!!
Nige
Senior Member
JAJ
Well-Known Member
Ah ok that’s what the local Cat guys said too.
It’s pretty rare to have a day time max temp as low as 10*C in winter, usual cold days might be 15-20*C. Over night temps do get around zero, rare times down to -3*C or so. Summer temps 40-45*C is pretty standard and high 45+ up to 50 in heat waves.
JAJ
Well-Known Member
An update on the saga. I have the machine home now and so time I can get into pulling stuff apart.
I had rechecked the trans pressures while it was still working and found the Torque Converter pressures were getting very low when it got hot. I left the gauge on the TC while working and it seems to get lower the hotter it got, from in spec cold to low hot. I know that is what happens as things heat up but I figured the outlet relief valve needed to be checked, cleaned and adjusted.
Pulled the outlet relief valve off and apart last night and it has only one spring and no shims. The parts diagrams say it should have an outer and inner spring and lists 5 shims. Nige stated on another tread i was watching that the listed amount of shims is the starting point so I will start from there with new springs.
I am hoping this is a big part of problems. Will order new springs and enough shims to do any adjusting that is needed as well.
I think its interesting as the images in the shop manual show only one spring in the disassembly pics, but the parts manual clearly show two springs, so not sure if this was updated at some stage?
I had rechecked the trans pressures while it was still working and found the Torque Converter pressures were getting very low when it got hot. I left the gauge on the TC while working and it seems to get lower the hotter it got, from in spec cold to low hot. I know that is what happens as things heat up but I figured the outlet relief valve needed to be checked, cleaned and adjusted.
Pulled the outlet relief valve off and apart last night and it has only one spring and no shims. The parts diagrams say it should have an outer and inner spring and lists 5 shims. Nige stated on another tread i was watching that the listed amount of shims is the starting point so I will start from there with new springs.
I am hoping this is a big part of problems. Will order new springs and enough shims to do any adjusting that is needed as well.
I think its interesting as the images in the shop manual show only one spring in the disassembly pics, but the parts manual clearly show two springs, so not sure if this was updated at some stage?
Nige
Senior Member
Buy 5 shims by all means + all the other replaceable bits of the converter outlet relief valve, not just the spring.
I would suggest that you start with maybe 3 shims and go up or down from there to achieve the specified pressure. Remember that you have to test the converter outlet pressure with the oil at normal operating temperature, around 80C as a minimum.
I’ll have a look at the parts tomorrow regarding the springs, etc, as it applies to your particular Serial Number.