Cat D6H LGP 2 overheating engine (coolant restrictor?)

[JAJ]

Hi everyone I created an account on the forum ages ago but this is my first post, I hope I am doing everything the right way, if I am not following the correct procedure please let me know. Don’t want to start off on the wrong foot. This place is a wealth of knowledge and I hope I might be able to help add a little bit to the community in the future. I am an owner/operator of a small fleet of machines and I do almost all of my own repairs and maintenance so fingers crossed that I can be helpful to others on here as well.
Anyway on to my question!

So I have a series 2 D6H LGP dozer that I have had for 4 years and have had over heating dramas (engine and trans) ever since I have had it. As we have worked through everything we have been getting it better over time. We thought we finally had it all sorted but as it has heated up here in Australia (our summer at the moment) the dozer is again getting hot, engine only now.
I was helping a friend with his d6h the other day chasing an overheating drama as well and he had been told about this flow restrictor in top radiator hose. The story was that this was part of specing the dozers for cold climates and that it could cause over heating in hot climates and it should be removed. It wasn’t the drama with that dozer but I am pretty sure mine has one as well (going to check in the next couple of days) and I wonder if this could be the final drama with my machine.
Has anyone seen these restrictors before and is there any truth to the cold climate spec up story?
My 966G loader definitely doesn’t have one so I had just assumed it must have been a dozer thing, couldn’t work out the purpose though. Can’t find anything about it on SIS or anywhere on the internet, so I am hoping someone can shed some light on it for me.
My serial no.
Sn: 4GG05795
Best regards
Jason

 

[Nige]

he had been told about this flow restrictor in top radiator hose.

By the fella in the pub I suppose.?
TBH I've never heard of it but that doesn't mean much.
Why don't you just remove the top radiator hose and take a look.? That would remove all doubt.

Is this the only D6H you have.?
What sort of work is it doing and how do you go about cleaning radiators.?
What coolant do you use.?
A list of what you've done so far to improve the situation might also help.
Oh, and some photos as well, but you will need to make a minimum of 3 posts on the forum before you can upload them.

 

[Delmer]

I don't know CAT's but I've never heard of such a thing, and I know cold climates and heat flow. It doesn't sound impossible that something like that would have been made, just never seen it. The temperature drop across the radiator should tell if something like that is contributing. Work until it's borderline overheating, take the temp of the coolant going to the radiator, and coming back. The top and bottom of the radiator work as long as they're painted surfaces, or the ports on the engine.

 

[JAJ]

Hi guys thanks for the responses.
I only have the one D6h, I do have a D6C but it’s not similar enough to test against I don’t think.
Haha yeah Nige almost… the mechanic that rebuilt the engine in the friends dozer before he purchased it. There had already been some conflicting stories from him so I wasn’t sure if I should believe it or not!! Apparently the restrictor could mean an extra 5*C. The restrictor was definitely there on that dozer though, the friend said make the hole bigger so we did. I forgot to take a pic of it but I will if mine has one when we check the thermostat tomorrow. We couldn’t tell for certain how much of a difference it made because we replaced plugged coolers at the same time on that machine. The restrictor was in the outlet from the thermostat housing and reduced it from full size back to a bit over about half size if I recall correctly. Wish I had measured it, will on mine if it’s there.

Anyway yeah cleaning radiators is a huge thing for us, same as air filters. We struggle with fine red dust especially on the dozer. They are usually blown out with compressed air daily or every couple of days if the conditions are better. We wash them with a steam cleaner every chance we get if they need it. The dozer has been sitting at the job for a couple months and is a long way from base so we took a water tank and Honda water pump to it the other day to flush it out. It’s not perfectly clean but it’s not enough of an excuse either.
It is running green coolant.
I took pics of the temps after flushing but before I changed the fan belts (which were worn out). So I’ll take some more temps as well tomorrow. I think there was still about a 4*C drop from top to bottom but will confirm. Top hose was around 104*C. The temp of the afternoon was 44*C so anything will be warm in this weather, but I thought if there was any truth to the magical 5* cooler it would be very helpful.
The dozer is pushing an 18ft stickrake clearing fence lines and fire brakes on a cattle station. So it is traveling forward pushing a lot more than reversing.
I will do another post of a list of what we have done on our journey to getting the dozer cooler so far. That should hopefully get me three posts and let me post pictures.

 

[Delmer]

In hot air temps like that, airflow is critical, and that's a tough job to keep a radiator clean. Soaking with detergent, rinsing and repeating are needed to get dirt out. Or remove the radiator, or coolers in front to get better access and rinse until clean. Pulleys wearing out will cause slip and wear the belts faster also.

Are you running 50/50 coolant, and has it always run that? If it's had water added, then there's the possibility of mineral deposits blocking the radiator tubes. You might check into 40/60 or even 30/70 coolant mixes, water moves heat much better than glycol, but you'd have to change the coolant sooner just because there's less of it.

I'm still suspicious of the restrictor. I'd love to see a picture and location. I don't think it's a significant factor in the overheating though.
edit: It turns out coolant restrictors are easy to find, either washers or thicker aluminum pieces to do just what you say, restrict the coolant flow. I assume for "high performance" use without a thermostat. I don't see a purpose for one with a thermostat in place, and you'd never want to run a diesel without a thermostat, nearly all have a bypass that the thermostat has to block off.

 

[Nige]

When you go in there take a good look at the thermostat and post details of it.
If you find the famous restrictor have a good look for a Part numbetr on it in addition to taking photos.
Do you dilute the green coolant yourself from concentrate or buy it premixed.? TBH I'd suggest switching to Cat premixed Red ELC whatever your answer is.
4*C difference from top to bottom of the radiator is waaaaaay off, even in 44*C ambient temperatures. You should be looking for somewhere close to 10.

I took pics of the temps after flushing but before I changed the fan belts (which were worn out).

Have you done any more work on the fan drive.? Pulleys, tensioner, etc, etc.? What sort of state are they in.? What about the condition of the fan spider itself.?

 

[JAJ]

Sorry I got got dragged away from my post with list of things done so far. Ill post the list and then answer the couple of extra posts.
I should have started talking to you guys at the beginning... I think you would have saved me a lot of headaches!

Purchased the machine from a bloke that had got it from the auctions and said he hadn't done any work with it or on it. It looked like it had been neglected a bit but components and engine looked and sounded good. I think reading between the lines he was being forced to sell it and the 966G loader I also got as part of a package deal. It was cheap enough to take a risk on it with a budget for repairs. Dug up history on it since and engine and TC only have about 4500Hrs I think if I remember right. Engine done by Cat dealer and Torque Converter was exchanged reman.

We got it home and it would run hot (engine and trans) when worked.
Did an engine service. Then started off with the simplest stuff first, coolant was bad and dirty. So flushed and cleaned and flushed again ect till all seemed clean. Then refilled with new coolant 50/50 green concentrate mixed with rain water.
Radiator needed steam cleaning.
Ran warm but ok after that for a while, but temps slowly started going up again.

Once i got the stickrake and start doing clearing jobs it was getting too hot. I blew a track adjuster and had to transport it home to fix that so while it was home we went through the cooling system properly. Found flaky rust chunks in the engine oil cooler blocking about 1/3 of it and trans cooler clean. The rust chunks were coming from the top and bottom radiator tanks it turned out. Prior to pulling everything apart the infrared gun was showing temp fluctuations all over the radiator cores so I figured the rust had blocked the cores internally and they looked a bit worse for wear anyway. Some looked older than others as well so we just replaced all the cores. Getting the rust cleaned out of the top and bottom tanks was a chore but we got them cleaned eventually and reassembled it.
Swapped the thermostat with a new one.The old one tested ok afterwards when we checked it.
Checked water pump.
New Radiator pressure cap
It needed a new alternator so fitted one with new pulley.
Fitted new "aftermarket Fan belts" that made all the pulleys look worn. I only realized when I tried the old belts back on last week that the old genuine cat belts fit the pulleys better than the aftermarket ones did when they were new!!! They were on there for 400hrs but I will only use genuine belts from now on. I was under pressure to get the machine back to work and over looked this at the time, a very silly mistake.
Machine went back to work and was warmer than I wanted but ok.
Checked Trans pressures and they seemed to be acceptable

It was ok till that summer and then got too hot again.
This time it looked like the Trans was getting hot and dragging the coolant temp up.
At this stage I rechecked the engine oil cooler expecting to find more rust blockages but it was completely clean.
Checked for combustion leaks into coolant.
Trans pressures were rechecked and things were within spec but on the low side especially the Trans lube circuit which is last in line. I reasoned that there was low oil flow to the Trans cooler. At this stage I found that the torque converter didn't have many hours, it pushed well and the oil was clean. I took the leap of faith to replace the transmission pump and that seemed to fix all the trans heating problems.
All was then good through winter, coolant temp stayed at 95*C and Trans temp hovered around 100-105*C when working hard. I was hoping the coolant temp would have been a little cooler but it could keep it there.

Summer again now and it looks like what we are left with is an engine heating issue.
The old fan belts i put back on sit just proud of the pulleys and more air seems to be getting pushed out the radiator. They definitely made a difference but it still seems to be generating more heat than it can get rid of and when it gets up over 104*C it takes a long time to get back under 100* at high idle. I have new fan belts coming to rule that out completely but getting parts here takes a while.
This left me with that restrictor removal idea and checking injection timing in case it is out a small amount. Any other ideas are very welcome, I am running out of ideas of my own.

 

[JAJ]

Yeah i thought that 8-10*C difference was what i should be seeing. I don't know if that restrictor could contribute to that or not?
The gap between the fan and shroud looks a little larger than it should be but lots of air is coming out the front still.
I thought i would put a new thermostat in just in case that is contributing, while looking for the restrictor. Do you think its worth doing?

The Cat Red ELC premixed is sounding like a good move.

I found the restrictor plates mentioned with high performance cars exactly like you say but nothing about construction machines. Yes you couldn't run this engine (Cat 3306) without the thermostat because it blocks the by-pass like you said. The only use i could come up with that made sense was to add back pressure on the water pump to stop cavitation, found that mentioned where some people were arguing over whether cars overheat with thermostats removed. But if that was the reason it was there all 3306's would have it I guess... not sure?

I hope my memory is right that there is one in my dozer so i can get a pic

Its a 2hr drive to get to the machine so if there is any other test you guys think I should add to my list while I am there let me know
Thanks heaps

 

[Nige]

I haven't checked the Parts Manual for your machine but aren't there supposed to be like sheet rubber baffles to close all the gaps between the radiator and the shroud.?

The Cat Red ELC premixed is sounding like a good move.

There is also fluid for hot climates like yours. It's called ELI (Extended Life Inhibitor), basically it has all the chemicals to protect engine components but no anti-freeze capability because it's not needed. You could enquire at your dealer if they stock it. See attached.

 

[Delmer]

If the restrictor is doing anything, it will reduce the flow of coolant through the radiator, and cause the temperature drop to be higher, because there's less hot coolant flow to keep the radiator hot all the way through. The low temperature drop suggests that the airflow is limited, BUT if the airflow is really bad, and the coolant flow is only a little reduced, you could get the same low temp drop. I'd guess that the new cores are doing their job by moving coolant well, but are somewhat dirty outside, combined with some slipping at the pulleys, combined with some air leakage from the shroud. Check the radiator with a light on the other side to see how much dirt is there, you can't see anything from the surface, unless it's completely plugged.

Cavitation shouldn't be an issue if the cap holds pressure. Remove the restrictor entirely if it's a separate piece like the examples online. Check the wear on the pulleys with a small straight edge, they will get rounded out on the sides in the middle and bottom, so the profile won't look like a sharp flat bottom V, but rounded out sides.

You know the coolant was bad and there was a lot of rust. I'd backflush the radiator but removing both hoses and cap, stuff a rag and an air gun in the bottom and a garden hose running in the top. When the water overflows, give it a shot of air, repeat until there's no more sediment coming out. Run it a couple hours with the coolant left in the engine and the rest filled with rainwater, drain into a white bucket and repeat until there's no more sediment. That ELI sounds like good stuff, water has a lower viscosity, higher heat capacity, and lower corrosiveness than glycol. Better all around if it never freezes there.

 

[tctractors]

The only flow restrictor I can think of used on a 3306 is built on the spiggot that bolts down the temp' regulator, the bit with the 4 bolts in that is, it's used on some wheeled loading shovels with out a regulator fitted (I seem to think) it's not something I have seen fitted on a D6 anything, there is a transmission cooler air blown on the dash 2 that is regulator controlled as well as the water heat exchanger by the engine oil filter, the cooled water goes through the water pump into the engine oil cooler, then the water travels into the top of the transmission oil cooler flowing down 1 half then turning at the bottom and then heading up the other half of the cooler, after this the water enters the side of the cylinder block travelling around the liners and heading up into the cylinder head via the insert directors that are placed in the spacer plate, if you have completely stripped all the water coolers and rodded out every hole and done all the work to the Rad the temp should be running sweet, I have had to strip the head and pull the liners on engines that seemed to have been filled with dirt but this was spotted through the water hole that enters the block with the cooler removed, you could see the sludge build up. tctractors.

 

[heymccall]

Sounds like water pumps were improved in 2014.

 

[heymccall]

What is a "water director" on that motor?

 

[Nige]

if you have completely stripped all the water coolers and rodded out every hole and done all the work to the Rad the temp should be running sweet, I have had to strip the head and pull the liners on engines that seemed to have been filled with dirt but this was spotted through the water hole that enters the block with the cooler removed, you could see the sludge build up.

TC has a point. If the radiator was as bad as you say it was what's the probability that the cylinder block and cylinder head are in a similar condition.? Is it worth pulling the cooler for a look-see.?

What is a "water director" on that motor?

From the SysOp
"The coolant enters the block and flows around cylinder liners and up through the coolant directors into cylinder head. The coolant directors make the coolant flow around the valves and around the exhaust ports in the cylinder head. The coolant now goes to the front of the cylinder head. At the front of the cylinder head water temperature regulator controls the direction of the coolant flow. If the coolant temperature is less than normal for engine operation, the water temperature regulator is closed. The coolant must go through internal bypass to the water pump. When the coolant gets to the temperature of normal operation the water temperature regulator opens and most of the coolant flows through radiator inlet line to the radiator. A part of the coolant still goes through internal bypass."

 

[JAJ]

My plans to get to the dozer have been put back till tomorrow now. Got stuck here at home carting water for thirsty goats today.

Nige Re the rubber baffles
I was thinking about the rubber strip that takes up the gap around the outer diameter of the fan, I didn't even think about rubber baffles on this machine. The way the fan shroud bolts straight onto the back of the Rad frame I didn't think they would be needed. Checked the parts diagram and they are sure supposed to be there though! Will have a go at posting the diagram. Looking at the parts diagram it seems the are set up to stop air that has passed through the Rad from recirculating around inside the engine compartment and going through again, more than actually directing the air through from the fan. Not sure on that until I actually look at the machine. It has been over 12 months since I had the Rad apart and I cant remember if they were there or not.
If they are to stop recirculating of the hot air and are missing, I am thinking this could be the drama?
When we swapped the belts it changed the tone of the fan and it seems like its moving a lot of air, but if it is sending hot air through again that would explain why when it gets hot it doesn't want to cool down in a hurry.... I hope its as simple as this??

 

[JAJ]

Thanks TC
That restrictor on the wheel shovels sounds exactly like the one we found on my friends D6H and what i recall seeing on mine. Will get a pic tomorrow if mine has one. Both machines have thermostats too. I thought it might play some part in my problem, but it causing a bigger drop in the Rad like Delmer explained makes more sense.

When we were trying to flush the old Radiator, before we made the decision to replace it, we got a lot of sediment out, even run a laundry powder mix in it for a bit which removed a lot more than we got with just water. When we pulled the radiator out and seeing what was in the top and bottom tanks I was expecting something like you spoke of in the engine. When we looked in the side of the block (cooler bonnet piece removed) and under thermostat, the engine looked very clean. Cleanest part of the system. So I dont think I have the problem in the cylinder block and head like you said you have seen.
I am really hoping i dont have to pull the engine apart to check inside... fingers crossed its something simple I have over looked like the baffles

 

[Nige]

Daft question. Is the fan spider installed the right way round.? Installed backwards it will still push air forwards through the radiator, just not as much as it should. Post a photo if you’re not sure.

 

[JAJ]

Thanks Delmer
Making the Rad hose temp diff bigger makes more sense due to keeping it in the Rad longer for sure. I was thinking if it stays in the engine longer it might pick up more heat a bit like a stuck thermostat and eventually add more heat than the system can get rid of? This is my crazy theory that I came up with when I ran out of more plausible options to chase... the more I think about it the less sense it make though.
Missing baffles like Nige said sounds much more likely than my idea!

The pulleys looked ok to me but I will get some pics and see what you think if you dont mind please. I thought they must have been buggered even though they looked ok till I put the Cat belts back on and they fit properly. The fan sounds like it is louder and has a different tone with the cat belts on and seems to be moving more air out the front now. Took a little longer to heat up as well.
I dont think I am getting any slip but like you said a little bit of everything could be adding up to my problem.

That way of unplugging the radiator cores with water and air sounds very good. I have kept the old core sections so I'll try it out when i get a chance.

Anyway thanks again everyone I'll get to bed and report back tomorrow!!!

 

[JAJ]

Ohhh good question Nige I dont know. I have seen it mentioned on here before but i forgot to ask about it.
Ill get pics tomorrow and see what you think
Thanks

 

[Nige]

When you post a pic of the spider be sure to indicate in which direction the fan rotates.