My truck was overheating about six months ago. I ended up replacing the water pump, thermostat and radiator. Well it worked. The other day I was driving and the bottom hose coming from the radiator popped off causing it to overheat. I towed it home and put it back on filled it with water and antifreeze and it ran fine. I went and had the oil changed and now it is overheating. The radiator has graphite looking shavings in the radiator. I really need to know what to do. Can someone please give me some suggestions.

Have you back-flushed the system, including heater core? Crud tends to settle around the lower radiator hose. Was the replacement radiator brand new? Otherwise, phosphate scale may be blocking passages in the radiator.

After back-flushing the system with a garden hose, I would replace the radiator if it was not brand, remove both drain plugs on the engine block and drain the complete system. Refill with a 50/50 mixture of automaker recommended antifreeze and distilled water.

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Originally Posted by TxGreaseMonkey

Have you back-flushed the system, including heater core? Crud tends to settle around the lower radiator hose. Was the replacement radiator brand new? Otherwise, phosphate scale may be blocking passages in the radiator.

After back-flushing the system with a garden hose, I would replace the radiator if it was not brand, remove both drain plugs on the engine block and drain the complete system. Refill with a 50/50 mixture of automaker recommended antifreeze and distilled water.

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The radiator was brand new. It only runs hot when you drive it. It can idle for an hour and the tenp gauge does not budge.

Read the link below, paying particular attention to Item 3:

https://www.askmehelpdesk.com/cars-t...tml#post235973

Fixed problem HERE...



We changed thermostat, belts, water pump, fan, fan clutch, hoses... you name it we changed it. Nothing worked. Just before we ordered a new radiator I took a few pics sent them to my dad and instantly he said to remove the bleeder bolt then fill radiator. That's it guys months of overheating a lot of money and hours of work when in the end it was so simple, cost nothing and took 2 minutes.



Turns out most the Nissan motors have a type of bleeder bolt or something (not sure what its called exactly) on top of the motor and that should be removed while filling radiator. Step 1 wait till engine is cooled down all the way. Step 2 remove radiator cap. Step 3 remove the bleeder bolt on top of motor (look around for it. Its just a little old bolt all alone) step 4 slowly fill radiator until coolant/water to come out of the bleeder hole. Step 5 put bleeder bolt back in. step 6 put radiator cap back on. That's it. Good luck





If you do not do these steps air get caught in the system and when heated turns to steam. And your radiator can't circulate that steam because the hot air raises. The steam will just sit at the top of the motor and block the coolant/water from circulating through the radiator like it should. Without it passing through the radiator correctly it will not cool. Having a new radiator helps because when they installed it they probably filled it correctly (by removing that bleeder bolt). They knew they could have just filled the old one correctly but there isn't any $$$money$$$ in that for them.

Okay, so what if your mechanic vacuumed out all of the air in the system until the hoses collapsed and it still overheats?

I'm not a pro by any means. All I know is what I did worked for me. Follow the steps on my previous post and see if it makes a difference. If there is already fluid in your system; 1 remove radiator cap (when engine is cool) 2 then remove the bleeder bolt on top of the motor and see if any fluid comes out. Add fluid slowly until it does. 3 Put bleeder bolt back in then put radiator cap back on. Hope this helps.