99 K3500 454 overheats under throttle

[1965truckrod]

Actually it was the knock sensor. Found the second wire, crimped and heat shrank a new pigtail on it and now it runs like it’s supposed to. I’ve heard that a bad knock sensor will pull timing out of the engine and make it run like crap. Either way. Runs good now.

My reply was too late, glad you found the issue.

 

[Frank Enstein]

Guys at the Bus Plant had to work on the roof of City Buses, installing roof-mounted A/C units, paint repairs, etc.

The bus might be ten feet high. Probably not even.

They'd have to get strapped-up in a Safety Harness, and tie-off to the structure of the bus, so if they fell, the harness would catch them before they hit the floor and broke the concrete with their heads.

They'd use a twenty-foot strap on the harness, so they had a reasonable work radius from the tie-off point--ten feet forward, ten feet rearward.

One day, the Supervisor asked "What good does a 20-foot strap do, when it's only ten feet to the ground."

I would have thought the supervisor gave them the 20 foot strap!

 

[Doctor Diesel]

Bit late to the party. I’ve had many a truck, gas and diesels, come into my shop with this EXACT same issue. 90% of the time it’s two issues, either the radiator/condenser/coolers are plugged and/or the cooling system has never been serviced. Here’s what my guys will typically do:

Theyll pressure test the radiator caps first and foremost along with the system to check for leaks

They will take A coolant sample and look for obvious floating buildup. A magnet will attract rust to the container side and a flashlight will make scale show easier

System is fully drained. Grill is pulled. Radiator is pulled. Radiator is taken, power washed, soaped with ZEP PURPLE, washed and repeated. Many trucks have issues with the lower radiator plugging from years of road grime, farm trucks are the worst. When power washing, wash back to front, use he washer proportion valve to appply the ZEP. The stuff can eat aluminum. Do not let it dry. Inspect radiator fins. Rinse and repeat as needed and straighten fins. When power washing, a very, very low pressure is all that’s required working top to bottom, never side to side. With radiator out, all coolers and condenser get the same treatment but remain in the vehicle. That way there’s no draining or R-134 recovery needed. If the coolers or condenser are plugged, radiator airflow is gonna get restricted

The fan blades are washed, degreased and rinsed. Dirty blades dont move an Ada quart volume of air especially under a heavy, low speed load.

hoses are all inspect inside. We recommend replacing them Regardless

System gets flushed until clean, fully drained including engine drain plugs, and filled. We don’t use DexCool. We fill 50/50 Rotella ELC NF which is superior in every way specially for heavy load aplications or big engines. That and Rotella won’t eat up seal like DexCool did to these early vehicles.

When it all said and done, the engine is run to NOT and fan engagement is checked.

Like I said, it fixes 90% of these overheat issues. Other things to check are a possible small, not yet failed, head gasket leak along with a bad water pump. However, maintained systems rarely have pump failures and checking pump flow and pressure is easy for a shop but kinda technically iffy in the driveway.

The clean, flush and fill should take an afternoon to do. The part that takes the longest is the flush and fill believe it or not. Good luck and let me know if you run into a snag

EDIT: Good lord. Little too late lol. Hope everyone else can use the info though