How hot is to hot?

[BigBlackTurd]

Hey, guys I have a m-1010 that has a pickup bed on it. Friday I was hauling a load of firewood about 2 1/4 rick, and while pulling a 4 mile grade in 2nd gear at about 35 mph. The engine temp was up to 220 when I topped the hill, it fell to 190 within a couple of miles. It has a 180 thermostat and new antifreeze. Will a temp of 220 damage the engine? How do I check the fan clutch, should I pull the radiator and have it checked by a shop? Any ideas.

Thanks, Brad

 

[Jones]

Up to 220 under a heavy load is to be expected if the cooling system needs a flush. As long as you didn't hold it there for 10 or 15 minutes you should be OK.
When the vehicle is up to operating temp you shouldn't open the radiator cap because the pressurized water isn't boiling even though the temp is over 212 degrees. Opening the cap relieves the pressure and allows the super-heated water to boil and to turn to steam immediately. However, if the cooling system has boiled over already, some tricks to keep damage to a minimum are; carry extra water and an old bath towel.
The spare water is obvious and the towel doubled over a couple of times and placed over the radiator cap will contain the spray and steam and keep you from getting scalded.
Keep the engine running while you refill the radiator; cold water on hot engine parts can crack heads and cylinders but with the engine running, the water circulation carries off the excess heat but doesn't create hot and cold spots because of the continued combustion.
With the engine cold the fan clutch should turn but with resistance. If it turns too freely or doesn't turn at all without slipping the pulley, it's time for another fan clutch. Take a look into the radiator tank and see what the ends of the tubes in the core look like. If the ends are crusted over then the radiator should be rodded out.

 

[chuck500cc]

Also. If there is not at least a 15* diff. between upper and lower hoses you need a rad. No cooling flush will cure that in the long run. Upper hot, lower cold..so to speak.

Chuck XD Fan

 

[mangus580]

220 should be ok for short times... but DONT go over that with a 6.2...... Bad things will happen

 

[BobS]

The original TAACOM specs was 235 degrees F, peak temp (stabilized), at 0.7 tractive effort on a 0 % grade (flat road).

The "0.7 tractive effort" means that the drawbar pull on a towing dyno is equal to seven tenths of the spec'ed gross combined weight of the vehicle and towed load, at maximum speed (usually around 5-8mph in top gear)without exceeding 235 degrees F at the engine out location (or the radiator inlet) the test usually takes anywhere from 30 minutes (failing by exceeding the required stabilized temp) to 8 hours (stabilizing the temp at 235) to run, depending on ambient temps. The 15 degree delta T across the radiator is also a must, as mentioned by chuck500cc, above.

 

[CUCVFAN]

Agreed. Considering the original t-stat is 195 degree, 220 is not a problem. These engines were designed to run hotter than 180. I wouldn't want to run it at 220 all day, but it didn't hurt anything.

What kind of gauge are you using? I had a factory gauge in my civvy truk that read 20 degrees higher than it actually was. It always read about 210-220 under any moderate load. I always thought it ran hot until I swapped in a high-flow 180 t-stat. Then, it read 200. Finally put an aftermarket gauge in and it read correctly.

You'll hear the roar of the fan if the clutch is working and you're running anywhere near 210-220 when you take off from a stop at those temps. Otherwise, use a heat gun to heat the clutch (not too long - don't want to damage it), then try to turn the fan. It should turn tightly. Then, start the engine and rev it up a little. The fan should roar noticeably more than it does when the truck has been running at normal temp and you rev it up in the same manner.