New piece of information from the current owner that sounds significant - when it was last operating that bulldozer had "issues with overheating" which doesn't sound ominous at all...

Not sure where to start with troubleshooting this one. Does anyone have any recommendations? I guess my starting point would be flushing the cooling system. I know that the water that is in it is pretty rusty, so perhaps we are dealing with corroded cooling channels?

Any thoughts appreciated.

Hi, LangdonStevenson.
Overheating can have a few causes, from as simple as the fan belt slipping to clogged cores from dust, dirt, grass, etc., to blocked tubes in the core to a cracked head or leaking head gasket. I think I'd look at getting it running and warmed up with the radiator cap OFF and the radiator full to the top and look for any bubbles coming up in the water. No bubbles means itza fairly sure bet that the problem is with the radiator.

If the top pipe is getting hot but the bottom one is staying cold or MUCH cooler, the issue could well be blocked tubes - which MAY be helped by flushing but may also invlove dismantling the radiator to rod the tubes. If it comes to that, an old carpentry shop bandsaw blade with the teeth blunted on a grinder can be helpul.

Look through the core from the front to see if it is clear of dirt and/or debris. If you can have somebody move a torch - 'flashlight' for our American friends - behind the core, that would help with this inspection.

That jigger will have a fan belt tensioner built into the top pulley. Remove the locking tab and tap the back face of the pulley around to tighten the belt. Don't forget to put the locking tab back in when you are done tightening it. Don't laugh - I've seen it done. I think the disease is called S.A.S. - Short Attention Span.

Hope this helps.

Just my 0.02. (P.S. You're a braver man than I am living in Sydney. I am allergic to crowds and traffic jams.)

Thank you Deas, that's just what I needed. From what I have seen the core looks pretty clean from the outside, but I'll check with a torch as suggested. Fan belt is pretty tight, so it's probably not that.

Fingers crossed it's not a cracked head or bad head gasket! I'll put a bit of money on radiator core blockage, but I guess we will see. I'll get it running and we will go from there!

Hi, LangdonStevenson.
Yer welkum, Sir. Happy hunting.

Just my 0.02.

i could never pull start the pilot on our d4. i just couldnt get enough omph into it. dad could and he's twice my age. his reasoning was your just not doing it right. i used to cheat and use a electric motor and vee belt onto the flywheel and a prybar to pull tension against the motor.

yes by relay i ment solenoid. thats all electrically speaking a solenoid is just a heavy duty relay.
there was a fellow at toowoomba how did them but i think he has retired due to poor health.

Cat D 318 heads must be some of the toughest around as far as cracking, I have not heard of even one. If you have bubbles in the radiator 98% chance it is pre combustion chambers. They can rust out and leak combustion gas, or the washer seals under them need replacing, or worst case the seat in the head needs dressing. I have had poor seats seal with a real copper washer seal, when the steel copper painted ones failed.


The age of parts and the way most of the engines have had mostly other than pure demineralized water run in them, a rodding out of the core does wonders. It is a job most are able to do themselves. I have never had a broken cap screw on the cast iron parts that would not come by welding a nut on the broken pieces. Some I have welded 5 or 6 nuts on before it came, but it came without destroying the threads. And I don't claim to be a great welder.

I have started the rodding with pieces of old school gas welding rods. Gently tapping one in a ways, backing out, a shot of air, and more tapping it down. Then start a second rod by the first after you get the first all the way through. Then finish with a piece of aluminum flat stock I found a hardware store. I have done 4 without causing any new leaks. One had a leak that I had used gasket group on a stick pocked hole. I closed that tube with solder top and bottom. It is alway a bit of a worry with old radiators, but have had good results.

But start as Des said by cleaning the outside of the core very well, and make sure the belt is somewhat tight. As well as thermostats do fail, but make sure the old one is bad. As the last new ones out of a Cat box I saw for a 318 engine said MADE IN CHINA on them.

Fan -- The older Cats --- Thirty, Sixty had a fiber "clutch" on the fan shaft --- Not sure that is still a factor - worth a look as that had tendancey to slip and the fan not pull as much as it should. Just a simple look.

Suggestion on the starting engine --- being horizontal, open the petcocks on each cylinder and turn it over a few revolutions, make sure there is nothing in the cylinders to cause an issue. Hydrolocking is not friendly to components. Good habit to form, as important as checking fluids and following other procedures.

CTS

Trainzkid88 - having turned over the pony motor on the D6 a few times out of curiosity I can totally understand!

I'm thinking that I may be better off just replacing the solenoid on the starter.  I can't see how I can disassemble it, and it's just a switch, so it seems reasonable to replace it.  I found what I think is the right kind of unit and it is only $40.  I'll talk to my mechanic about it too.  See what he says.

Ray54 - that's really good to know about the D318 heads being strong. That's interesting about the pre combustion chambers,  I wasn't aware that they were a thing!  Having done some research I now see that they are replaceable (and available) parts, so that's good to know.  Thank you for the education.

I hope that I don't have to pull the radiator and rod the cores, but if it needs doing then ok.  That will be after I have gotten it running and decided if it's worth pursuing.  Definitely will give the exterior of the core a good clean first and see if that helps - as I said it looks pretty clean, but I may not have been looking closely enough!

Regarding the thermostat - see the photo below.  Houston, we have a problem!  Seriously though, from what I can see, that's the thermostat sensor hanging off the side of the dozer.  So I'm not even sure how the owner would have known that it was overheating - hopefully not by it boiling the radiator like a kettle...

 

Regardless it looks like I'm going to have to renovate the thermostat and the oil pressure gauge.

CTS - thank you for the intel on the fan clutch, I'll check that out too.

Regarding the pony - yes that's exactly what I did.  It turns over fine with the petcocks open and you can hear it sucking and blowing through them.  Close them up and you get compression resistance, so the basics are all there! (and we now have spark, just got to get that fuel through).