Engine is overheating?

Stop leak clogs flow thru the heater core radiator etc if both the radiator hoses arent getting really hot your not getting flow thru your radiator. Thats why it ls getting too hot. Also are both your heater hoses going into your firewall getting really hot?Are you sure you got the spark plug wires routed cirrectly when you replaced them?

Both of these symptoms can be caused by low coolant level but with the parts you replaced already, at some point the system should have been filled.

The next thing is to feel the hoses when the overheating occurs. If the upper radiator hose is cool, a leaking head gasket might be a suspect. Combustion gases can pool under the thermostat and prevent it from opening. Thermostats have to be hit with hot liquid to open. Hot air won't do it. If the hose is hot, feel the two heater hoses. They should be too hot to hold onto for very long. If they are cool, the heater core is likely plugged. Remove the hoses from the engine, then run water through them from a garden hose. I prefer to not remove them at the heater core because besides limited access, on some cars you run the risk of breaking the solder bond between the pipe and the heater core, then you have an expensive leak.

Do you get hot air inside at highway speed?

If you had a blown headgasket you would have steam out the tail pipe and would be loosing coolant. You should still have flow in the cooling system though. What about the heater hoses are they getting really hot?

You won't have any hot air inside with the heater core bypassed.

If the upper radiator hose is hot near the radiator end, coolant is circulating. Feel across the radiator to see if there are some cold spots and some hot spots. If there are some of each, parts of the radiator are plugged. Normally that causes the engine to run hot at higher speeds, but sometimes the natural air flow at higher speeds brings the temperature down too. Also look for corroded cooling fins on the radiator. If they crumble when you touch them, it's time to replace the radiator.

If even the heater hoses are only getting warm you have a blockage. Remove the heater hoses and see how good water from a hoses flows thru it?Like I said before using coolant stop leak causes cloggs.

I think I'd start with a cooling system flush, then see if the entire top of the radiator is hot.

The AC problem is caused by the engine overheating. Have you tried replacing the thermostat or flushing the radiator? Does it ever overheat when you are moving? If not, chances are the fan clutch is bad and needs replaced.

Let me know.

Head gaskets aren't a common problem on truck engines, and they often leak coolant into the combustion chamber or combustion gases can go into the cooling system. When that happens, it is possible to see air bubbling in the overflow reservoir and confuse that with boiling coolant. The secret is there will be no steam associated with the bubbling. Leaking head gaskets also usually involve loss of coolant.

Another secret is if you're watching the temperature gauge, does the overheating occur at highway speeds? If it does not, suspect a problem with the thermostatic fan clutch. I've done this, and seen it done, but I don't recommend this for the squeemish: after you're sure the fan spins freely, and the engine is cold, hold onto the fan while a helper starts the engine. It won't be very hard to hold. As the engine warms up, you will feel the clutch starting to tug harder and harder on the fan. Do this at your own risk. I don't want you hunting me down on Halloween night with a roll of toilet paper! It's important to not let go of the fan slowly. It will bang your fingers. Let go real fast or just have your helper stop the engine. I've seen people use a rope too, just don't wind it around your wrist in case of the unlikely event the clutch seizes. Don't use a coat hanger either as it can do damage or injury if it gets launched.

A more sane approach is to listen to the fan. When started from cold, the engine will not overheat for at least a few minutes. As the engine warms up, you should hear the fan noise diminish as the clutch slippage decreases and the fan speeds up.

Another thing to be aware of is overheating can occur if the plastic radiator shroud is missing. Air will bypass the radiator or circulate around so hot air keeps going through it. If the overheating seems worse at highway speeds or in higher outside temperatures, look for rotted fins between the radiator's tubes. That happened to my '88 Grand Caravan many years ago thanks to living in the salt-use capital of the nation, Wisconsin. Anything over 60 mph and 60 degrees caused the temperature gauge to creep up higher than normal. A year later the same thing happened down to 35 degrees. It was due for a new radiator anyhow. I had patched six different leaks due to corrosion!

Another clue is to feel the air from the heater set on high when the overheating occurs. If the heated air is cooler than normal, circulation of the coolant has stopped or slowed. That COULD be a sign of a head gasket, or a broken water pump impeller. That won't be your problem with a new water pump, but it is fairly common on Volkswagens. If the air is really hot, and running the fan on high brings the temperature down, that would also point to cooling fins in the radiator. When my van ran hot, I ran the front and rear heaters. That brought the tempeature down real quickly.

Caradiodoc