Hi sorry for another delay in getting back to everyone. and for the long post
There is a few posts to answer so I will get to that in moment, bit of an update first. I worked the machine for a few hours yesterday to actually give it a good test to see how the improvements we have worked out so far are helping up to now and test with a door off as well. I couldn't hook a gauge up to test Radiator pressure with what I had with me but with everything up to temp, if you lift the valve on the rad cap it seemed to have quite a bit of pressure in there. So I'd say it would be working correctly. It has 50 stamped on the top so I expect that to be 50 Kpa (7.25psi). It is a genine Cat one and it looks like the one Cat lists on the website for it, I can find the old invoice and check part no. if you want?
So temp comes up rather quickly to 80*C then slowly rises to 91. It pauses around there for a while then slowly rose up to 98-100 and stayed there for a while but slowly crept up as the day got hotter. Around lunch time it was up around 104*C. I pulled one of the side doors off for awhile at this stage but it made no difference. I did notice at this stage too that the AC condenser was getting plugged up again (only done a few hours since last cleanout) so we blew that and the whole radiator out and air filter. Lots of dust came out of the rad core. I do an initial clean then repeat with engine at high idle to get extra out (best way I have came up with so far for field clean out) After doing this I expected that there would be even a small drop in temp... absolutely no change, it ran at 104*C for the rest of the afternoon. It was a 43* ambient temp afternoon so rather hot, but a cleaner radiator made no difference to the coolant temp!! More air through a cleaner radiator has to mean more heat out... if that was the problem wouldnt it? This is the key point that has had me stumped all along, and I blew it out mid way thought the day to make sure I wasn't just convincing my self that it was happening, about as scientific as I could come up with. Any other machine I have the moment the coolant temps rises above its normal range it signals time for a clean out and everthing goes back to normal.
I also double checked temps of the core sections and the temp drops from top to bottom were the same on all cores at the end of the afternoon. It was extremely hard to get accurate temps with the amount of hot air that was blasting out the front with it at mid Revs, what i imagine being in a fan forced oven feels like. I was thinking afterwards maybe I should have checked this as soon as the temp got to something like 93* so it hadnt had a chance to soaked though the Rad if things were blocked but I haven't convinced myself that it would make much difference. Happy to repeat if you guys think that would be better?
I forgot to take the tacho up yesterday to check fan speed as has been suggested but I am going back tomorrow because I want to take the muffler off to make sure an exhaust restriction isn't a contributing factor. This is something I realized I haven't checked yet and I wanted to rule it out.
That "Know your cooling system" is a very good read I have it saved on my phone for reference, there is also a dozer specific one as well that is an extra add on that I found a while ago. It added a few other things and I thought was worth reading too.
So up till this point of the thread I have tried to just state the facts as I see them and not bias them with my own opinions to much (hope everyone thinks I have done a good job of this). I didnt start the thread to find people to validate my ideas, I wanted to share the facts with some other like minded problem solvers and hopefully brainstorm a solution... and all of us(especially ME!!!!) learn a bit in the process. SO with that said I an going to give my interpretation of the facts and see what you guys think. I welcome to be corrected or challenged with anything I say, I am here to learn and are very grateful for what info and knowledge everyone has shared so far!!!!
Here is my take on what I see happening. The thermostat/regulator is matching up with pauses at the correct temps as per the specs so I think this should rule it out for misbehaving. I hear what Nige is getting at with higher coolant temp meaning better heat transfer but once you get to 97*C both regulators are going to be fully open and at max flow. This should mean that at that point the system would function the same regardless wouldn't it? As I understand it if heat keeps getting added after this then you get to a point where it should balance out at the systems capacity to shed the heat. I think this is what I am seeing when it levels off at around 100*C and the rises as the ambient temp goes up. Please set me straight if I have this wrong, but I think that is the theory isn't it?
A coolant temp of over 100*C is too hot isnt it? I just want to make sure that we all agree on that. Just thinking about it and if its not boiling and spewing coolant out is it really too hot? I am worried it is over 95*C but with high ambient temps what should I be aiming for? The manual suggests normal operating temp range is 75-93*C and the warning light should come on at 107*C.
Ok so if it is too hot, where is the heat coming from and why isn't it getting rid of it... the fact that I did the test with blowing the radiator out has me directed back at excess heating rather than not enough cooling. Just my thinking trail.... I could be and probably am incorrect.
The torque converter/trans temp (once everything heats up) is 5*C hotter than the coolant. It heats up a bit more if you load the machine right up and travel speed slows right down but cools off back to the 5* when the load is lessened. I don't let it slow down very much from rated speed with a load, once you notice and feel a slight difference in speed it's time to get rid of the pile and start again. So I am thinking thats an unlikely cause. That has me looking back at the engine.
I know the intake isnt sucking hot gasses back trough the dust ejector, but I dont know if the muffler might have a restriction. I think this could cause heating and it is about the last easy thing I can think of to check. I figure if I put a straight pipe on it and it makes no difference that is ruled out (going to try that tomorrow).
I'm not saying that the pulleys and belts are not still a possible factor but I am thinking unlikely. The pics I took were of the used Cat belts that I put back on, the new ones that I have coming still havent showed up yet. Have to chase them up. The old belts were sitting right down in the Vee's but these seem to be up ok.
The fan shroud is a small factor I believe for sure but I really think there is something else that is the more major cause. If its not the exhaust I really hope I am wrong!!!!!
I did have a overheating issue on a small Fiat dozer (first one I got) when I had the injector pump rebuilt. I got the timing a little out when i re installed it and it was lacking in power and overheated very quickly. So that is something I had wondered about but haven't checked yet.
Flushing the Coolant out where the machine is would be a challenge. I am looking forward to doing it and getting ELC or ELI in there but getting enough clean water to it where it is, is going to be hard. I have talked to the client and we can wait till the days cool off a bit to work it back to a source of rainwater if we need to as an option. When I do it I was thinking some cooling system restorer might be worth running through it as well? Might pick up some more efficiency in the radiator?
The water pump impeller (cast not plastic) looked good and clean when I had the cover off but I didnt take any pics. Do you think with the evidence we have it could still be a suspect?
Anyway looking forward to reading everyone's feedback on my theory's in the morning. I will get the fan and engine speeds tomorrow hopefully and test the exhaust idea. I think so far we have made a big improvement with the fact temps aren't continuing to climb and are actually now stopping. So we are winning bit by bit.
Bloody late here now so well past my bed time.
