Replaced my waterpump a couple of months back, new hoses and belt also.


Recently temp gauge started bouncing back and forth from normal temp to almost redline. As it would do this the heater would blow hot and cold respectively.


Couple of days ago I replaced the Thermostat. Truck ran fine and temp stayed constant just below 200 F (192 F Thermostat), drove about 10 miles total in town.


Last night driving on highway after about 20 miles, it began the "bouncing temp gauge" game again, with the heater doing the hot and cold air thing. Made it to my destination (an additional 20 miles) and parked. This morning I went out and saw that there was Antifreeze on my front bumper and along the side of my driver's side front fender. Lifted the hood to find Antifreeze had sprayed all over the engine compartment with the bulk of it around the upper radiator hose where it meets the radiator.


Current situation:
Engine runs strong and smooth
no water in oil
no oil in coolant
haven't run the engine yet
coolant seems to be coming from upper radiator hose
fan turns, does not wobble or anything weird
Radiator cap has white hard substance inside, as well as the overflow reservoir


Also: when temp gauge climbs I hear a hissing sound inside cab just before it bounces back to normal (it was also doing this before I put in new Thermostat, which I did not test before installing).


Suggestions?

 

You are losing coolant. Either the upper radiator hose is not sealing to the radiator, or, it has split somewhere. The wildly swinging temp gauge indicates low coolant. Works fine till it gets low enough the pump can cavitate, and pump air into the system. That's where the temp fluctuations come from.

If you can, put a pressure tester on it, pump it up, and see what happens.

Welcome to DF!

 

If u really wanna get it replace the whole cooling system

 

Last resort, going to try obvious remedies first...thanks though!


HeyYou: Thanks for the welcome and advice, headed to get a tester right now.


On another note but in the same vein: does it matter what color and brand my coolant is? Read on some posts that it does. I've been putting all kinds of coolant brands, but all the same green color. Going to check my Owners Manual for recommendations, otherwise any enlightenment would be much appreciated!

 

So long as it is green, what color bottle it is in, is irrelevant, it all comes from pretty much the same place in any event. Stay away from the orange stuff. Your cooling system WON'T like it.

 

So here’s where I am now:


Pressure test showed leak at upper radiator hose and thermostat housing. When I replaced the thermostat before, I guess I stripped out the bolt hole for the housing and thought that it was super torqued to the block but it was actually “seized” after going in only half-way. Removed housing/gasket, got new upper hose and gasket & RTV but…now what’s the easiest way to remedy the stripped bolt hole for a reasonably intelligent/somewhat sane person? I’m in California so I have another 3 hours before the parts store(s) close for the night.

 

With everything out of the way, try just running the bolt into the hole. Make sure it goes in STRAIGHT.

If the threads are really trashed, going to have to heli-coil it.

 

Helicoiled the bolt hole, put everything back together and went for a test drive. Everything went fine.
Drove about 60 highway miles with no problems, temp gauge stayed consistent. When I exited the highway and came to a stop, temp gauge shot up and went back to normal again.
Drove some city blocks and all fine.
This morning, was driving and temp shot up again, turned on heat it blew cold air.
Got home and opened hood, hissing and slight fluid leak from upper rad hose which was only lukewarm, bottom hose really warm!
Radiator? Heater core?

 

I have no actual input here. As HeyYou will know way more than me! But damn, a 60 mile test drive?? :P

 

LOL! I live 60 miles away from my mom, who I visit often so it was more of a "let's see if this worked" drive! But the original test was a couple days around my town before the 60 miler!