Ok, I replaced the head gaskets on this truck a couple years back and now I am having symptoms similar to the ones I was having then. I am not entirely convinced that this is what is wrong however.
Symptoms:
Truck was idling rough until it warmed up
Truck takes forever to warm up or simply does not warm up
If/when it warms up it operates at higher than normal temp/almost overheats(it hasn't overheated yet)
Heater blows very cold air
White smoke(has been cold outside so not sure if due to temp or coolant)
Overflow bubbled when I shut the truck off, but it has only happened once so far

I am kind of at a loss, but like I said am suspicious of the head gaskets.
Any ideas?

Thanks in advance!

 

Aquaman, when was your last coolent flush and thermostate change? does the fan come on when truck starts to heat up?and at what temp do you get up to.

 

Also whats the oil dip look like ? ( creamy) or black

 

Dipstick looks normal, oil is a little dirty but no creamy color, no sweet smell.
I haven't changed the thermostat or flushed the coolant for close to two years (d'oh!) so that is my next move. The truck seems to get to pretty close to operating temp, maybe a touch higher. I am not sure what you mean by does the fan come on.

Also the rough idle at start up seems to have disappeared..

 

Try a new thermostat?

 

Oh sorry I thought I was in the diesel section, in your case the clutch fan,and I would still change the thermostat , the spring gets week, I would do a flush with recommended coolent. and watch the oil on the dip after.

 

04bad... there is an EDIT button you can use instead of creating more posts if you need to add a thought, correct an error or make changes. Some on slow lines don't need more 'stuff' to download.

What vintage? Which engine? Did the heater work previously? Have you bled the heater core hoses of trapped air? Have you 'burped the hose from the thermostat housing to insure a full hose & top or side radiator tank? Is the overflow system working and keeping the radiator full of coolant or is there an air pocket?
To diagnose, a full cooling system is necessary, along with knowledge about the fan clutch. If you have a fan with a metallic center about 8-9 inches in diameter, with fins on the outer rim, you likely have a thermostatically controlled fan. When the air from the radiator passes over the control, it will close a valve, and engage the fan to the water pump much more firmly. When not needed, the fan can free wheel, and use less energy. The controls fail over time, and the fan will not engage, leading to an overstressed cooling system except when driving at highway speeds. In hot weather, standing still, if the device works, you will hear the fan speed up and slow down as the internal valve closes and opens.
You can use a pressure test to determine if you have leaks or cracked heads. You can also have the coolant analyzed by a sniffer to detect combustion by-products in the radiator & coolant. That could indicate head gaskets or cracks allowing gas into the cooling system.
tom
If you have a

 

Your symptoms are consistent with a blown head gasket.

When you replace the head gasket did you:
check the heads for flatness (hint, these are never flat)
have the head resurfaced if it wasn't flat
check the block for flatness (they are usually ok, but you still have to check)
replace the head bolts with new ones, the old bolts are NOT reusable)
torque the head bolts in proper sequence and torque the lower intake manifold in proper sequence.

 

Sounds like water pump may have lost impeller. Check radiator or coolant jug for bubbles while idling if it is a head gasket that will tell the tale.