Need help with overheating 454 Firetruck

[ARTEMIS1759]

This is for my Dad who is a volunteer Fire Fighter. They got an '89 Chevy 3500 454 5 speed. Owned since new. Not sure when it started but for sure last 10 years. Stuff I suggested and done to it. It is TBI. New engine, thermostat and CORRECT water pump. Aluminum Radiator, new hoses. Not sure on heater core. Problem is, is everytime they take it out it overheats. Brush setup on back. I was thinking maybe adding electric radiator fans and cooler thermostat. But, they were told you cannot get a cooler thermostat? Climate is in South Dakota so some hot days usually though 70-80 during the summer and cold winters. Plains type terrain, gravel and paved roads. Correct coolant mix also. I suggested mold sand in the passages, but on both engines? Throw me some ideas y'all...

 

[ARTEMIS1759]

Oh and it is a dually.

 

[90halfton]

Does the fan clutch act like it's engaging?

 

[ARTEMIS1759]

OK a little more info. It has 4x4 4 speed with dual electric fans. New fan clutch when engine replaced but don't know if they checked it. Factory heater core with flushed coolant. And I saw summit had cooler thermostat.

 

[wingman]

Check it has the spring inside the bottom hose......... Had a guy here years ago with a 454 RV complaining of overheating. Fitted the missing spring and the problem went away. The water pump sucks the hose flat with revs. Hope this helps!

 

[ARTEMIS1759]

I will have them check that. Thanks Wingman. Anyone else with other theories just in case. I am 1800 miles away so I figured I would give them a few options unless everyone concurs with Wingman.

 

[90halfton]

I will have them check that. Thanks Wingman. Anyone else with other theories just in case. I am 1800 miles away so I figured I would give them a few options unless everyone concurs with Wingman.

Nobody with sense will argue with what he said. That is definitely a real thing.

 

[ARTEMIS1759]

Nobody with sense will argue with what he said. That is definitely a real thing.

Well, I get that. I already told them to check that a few hours ago. I just was asking if anyone had any other suggestions.

 

[90halfton]

Well, I get that. I already told them to check that a few hours ago. I just was asking if anyone had any other suggestions.

Ah, gotcha

 

[AllThrottleNoBottle]

Just to be sure, how are they noticing the overheating? If it's just with the dash gauge, it could be the gauge sender or gauge. An infrared thermometer might be handy and is probably something a fire department has around. Now if we're talking it's 'puking coolant' hot, obviously I'm barking in the wrong forest.

Oh, for ***** and giggles, is it catalytic converter equipped? If so, I wonder if they or anything else exhaust-wise (muffler, etc.) is plugged or has ****** flow?