My 98 Ranger with 160k miles on it started overheating a few days ago. It was a hot day and I had been running the A/C. When I noticed the engine temp rising I switched to hot air for emergency relief and got nothing but cold air.

The reservoir was empty and steam was coming from the upper connection of radiator (highest point on coolant system). I refilled the reservoir with water and got home but it still was overheating with steam coming from the upper radiator connection.

I replaced the thermostat and water pump just in case (neither had any noticeable damage/defects but I will run the thermostat through boil test to make sure new one works).

After replacement work, took it for a test drive. It was still trying to overheat with no hot air coming from heater core. I'm not seeing any water in the cab and reservoir has been full of water ever since I refilled it.

Only other thing is I do hear an irregular metallic clicking sound when I press on the gas. Haven't been able to identify its source.

Thanks in advance for any suggestions and assistance.

 

You need to purge the air in the system when refilling, usually removing one of the heater hose will do that.

When engine is cold remove heater hose at the firewall or if it has a by-pass valve(4 hoses on a valve) remove a hose there, set heat setting in side cab to HOT.
Remove rad cap and fill rad until fluid is coming out heater hoses.

Reconnect hose leave rad cap off and start engine.
Let engine idle for 10 minutes, top up rad if level drops.
Heater should start blowing warm after 5 minutes

Watch rad opening for signs of bubbles, there should be none after 2 or 3 minutes, if there are bubbles then you could have a head gasket issue.
If you get sudden "boil over" in the first 10 minutes, then you do have a head gasket issue.

If rad level is stable, heater is hot and no bubbles then put on rad cap and test drive.

 

Thanks RonD!

Did as you said and took off one off the hoses at the by-pass valve and filled till fluid came out at the disconnect. Warm air in cab and an engine running at temperature. Also didn't see any bubbles so hopefully head gasket is ok.

Thanks again.

 

Good work