overheating 5.9

[warner]

I have a 90 non intercooled that Is overheating. I've replaced the thermostat water pump fan clutch belt coolant. I'm not sure what modifications the engine or pump have had. it runs strong as Hell . I shut it down before it got past the third mark on the gauge. it will idle forever but will start to get past it's normal range within ten miles. I'm new to this forum so I apologize if I've placed this in the wrong place.

 

[JLEONARD]

The non IC engines used a top flow style radiator as opposed to the newer cross flow style. My guess is that the radiator may be clogged (mine was but it was not overheating). You can try doing a flush with fresh water or one of the flushing compounds, but be advised you may end up with a leak afterward. I eventually replaced the radiator, it was not all that expensive.

 

[MLee]

When this problem was discovered back early in the day, the top flow was changed to a cross flow radiator. Here in SLC we had a shop that would modify the radiator and make it into a cross flow. You might be able to find a radiator that would fit and change it over. I checked with this shop for friend and they still do the change, cost might be cheaper than a new radiator. You might find one near you and inquire.

 

[cerberusiam]

Before spending a lot of money get a manual temp gauge on it to verify it is actually getting too warm. Frequently it was just a miscalibrated gauge and\or signal causing the a misrepresentation of coolant heat. You may find it is not really getting as warm as the gauge says it is.

 

[warner]

I stuck a temp gauge in the radiator and it read 200 . I have another rad and top neck I'm gonna try that and see if that works. this truck is my daily driver so I'm hoping is not anything to serious.

 

[goodguys75]

could it have air in the cooling system??? that will cause it to run hot, if not bleed properly......make sure you use distilled water and not a water hose for the water

 

[DVolk]

Did you put a OEM Cummins Thermostat in it ? If not Do that the same with the water pump . There is tons of issues with the non stock Cummins ones

 

[JR]

Do the lower radiator hoses on the early Cummins have the internal spiral rings to prevent them from collapsing? I have seen weakened hoses collapse on the suction side of the water pump under higher engine load. The higher the load, the more the pump sucks the hose down. Hard to catch while your under the hood, at idle the truck would run all day on a 90* day and not overheat. Take it down the road and within minutes the temp gauge would start climbing.

 

[DVolk]

The older ones do but most of the newer hoses dont

 

[HHhuntitall]

If it's only going to 200*, you probably got a thermostat from a major parts dealer like Orielly's or Napa. They only sell, that I"ve found, the 195* thermostat, and the factory ones are 180, IIRC. Try finding a Cummins thermostat, and it may fix your problem.....

Also, as mentioned above, check to make sure the radiator has been washed out on the outside, and the AC condenser isn't plugged, either. Flushing it might help, too. At cruise speeds, it shouldn't heat up. As it does it fairly quickly, I'd think it's the thermostat....

 

[RSchwarzli]

A few things to check. I ran th factory rad up until 3 years ago and this is what I found:

Even putting out 720 ft/lbs at the wheels, I could run 33 psi boost while GCW was at 20,000 in 90 F days at 70 MPH and was fine. The key is to ensure when you look through the rad with a flashlight behind that the cores are clean.

Also, shine a flashlight down the rad cap hole and see if the rad cores are closed shut from oxidation/garbage inside the rad.

I dont suspect it is a thermostat issue, and it doesn't sound like a gauge issue. In the end, mine was plugged on the inside so I had it recored with dual 3/4" core. That helped and as it could flow properly again due to open passages, that was a huge help!

 

[JLEONARD]

If you have a temperature gun you can check the radiator in several places to learn if you have hot and cold spots. That will tell you if your radiator is plugged or not.
Simple procedure takes about 1 minute after the truck is "overheating".
You can also shoot the temp sender and learn if your gage is telling the truth. You can find out if the T stat is opening also I think depending onwhere in the system is hot or cool.
Then there will be no guessing.

 

[DVolk]

If your not doing it , one thing to do once a year is add a cup of water soluible oil to the radaitor it prevents rust issues and lubricates the water pump . You casn buy the premixed , so called mixes to add to the radaitor but i dont , the oil disapates and dont cause any issues I have not changed my antifreeze in years its clean and still test -30 or better

My dad was a 30 year plus radaitor man

 

[HHhuntitall]

Not a bad idea.... but I prefer the water filters with the anti-cavitation powder recharge already in 'em.... Easy to install, easy to change, and no worries about any foreign buildup or corrosion.

 

[DVolk]

True either one works just a matter of preference or Economics , or Both !!!