MEngr- I'm not familiar with bottom by-pass thermostats- I haven't had to diagnose a cooling problem with a set up like this yet. What's the harm in running this set up without the thermostat?
MEngr,
I am not that familar with the Nissan, thnaks for the info.
Just wondering if you have checked the adjustment of inching linkage and changed transmission fluid and filter. all info and tips expressed are worth double cecking and make sure Radiator is performing as supposed to as Edward T advised and more than likely you will find your source of trouble. Good Luck!
rogeriwt;
I do believe you may want to wish to re-think your comment. bbforks suggestion is almost identical to the manufacture's recommendation. It is just missing a few other task which are included in Nissan's procedures to correct this issue.
Removal of the thermostat and running the engine without it, is not a wise procedure to take on a bottom by-pass thermostat. Removal of the thermostat and putting it in a calorimeter to check it's function is the OEM's recommended step to take.
Stupid suggestion: have you tried removing the thermostat to see if it changes anything?
If the surroundings affect the temp I believe it would be an air flow issue. If all the usual suspects are OK I would install vents in the hood assy & relocate the muffler (assuming it's in the middle & behind the radiator).
I have sold an identical Nissan CPJ02A-25PV to a fairly high cycle account that is having the identical overheating problem. The water pump has been replaced, the radiator is clean and the coolant is circulating fine. We have checked everything we can think of and it still runs very hot. It is OK in a wide open area but once it is operating in a confined area, such as truck unloading, it runs super hot.
Any suggestions?
A couple other thoughts -
1. Is engine timing set correctly?
2. Valves set correctly?
3. Does this unit have a cat converter? If so - if its "plugged" could be the issue?
all these are good suggestions, and if none of them pan out, or you have an IR temp gun to check the temps, you may find that trucks this young experience clogging of a percentage of the radiator tubes so that while there is circulation, there is not enough to keep water in the rad long enough for it to cool off. you may also find when you do start with the water pump that while the pump seals are good, the blades on the pump maybe rusted away and not pushing much water.
I would be looking at the transmission fluid and filter screen and make sure the inching is adjusted properly. I have had this problem and figured out that the operator kept "resting" his foot on the inching pedal all day and didn't realize it.
Make sure the fan is turned the right way and you didn't say if the water pump had been replaced or not, I'd start there with a new water pump & thermostat, make sure you bleed the system also of you'll have the same problem again real quick.
I've done the service work on lots of Nissan CPJ and H models with the H20 and H20 II motors and never had a overheating problem, even with dirty radiators. I guess the first step would be to check to see if the radiator is as hot as the motor when it overheats to prove the the coolant is circulating. Sounds like it isn't circulating good due to the thermostat or maybe the head water jackets are plugged. If the head gasket is bad and blowing combustion gases into the water, it will definately have problems.