Truck details: 1984 Toyota truck, 2WD, 5 speed, 22r My truck was running fine, then out of nowhere I started hearing these loud thud type noise from under my hood while driving and idling. After opening the hood and listening, I found that it was coming from the radiator (not the fan). It was causing these loud sucking noises and shaking the tubes and radiator. Now on my heat gauge, it goes into the red/overheating in a matter minutes of driving. When I turn off my truck and open the hood the radiator is making all these sucking noises for a minute or 2, which it never made before. My truck still feels like it runs fine, but the gauge says its overheating and then the radiator starts making noises. Any ideas?

 

huston we have a problem. Sounds like the radiator has joined forces with the dark side.maybe the piston(s) movement is drawing in water from the coolant system via the head gasket, or the timing chain finally wore a hole on the casing cover (typical of a high mileage beater r series motor).the latter is more likely.

 

I figured it out, it was the thermostat.

The thermostat is in between the engine and the radiator, mine had worn out and was blocking or limiting the amount of flow going to the engine.

It was simple to replace and only cost $6