I installed my new plugs and wires yesterday and the truck is running great. The problem is that the engine temperature is barely getting in to the normal operating range and when heading down the highway it actually cools to the point of being out of the operating range on the gauge. I really don't think there is a connection between the new plugs and wires and the engine not warming up but it seems like a huge coincidence.

To troubleshoot, I tried to bleed the cooling system but could not get the engine warm enough to accomplish that. I let the truck run with the cap off the coolant tank far about 45 minutes with no change. My coolant level never moved while it was running. I'm thinking that the thermostat may be stuck open. Anyone have any other ideas? Going to pick up a thermostat and gasket while I'm out running errands.

 

check and clean contacts for engine temp sensor, you might of knocked connection loose when replacing plugs/wires.

 

Replace your thermostat and gasket, bleed the system and all will be well.

 

Ditto on Spike's comment - get 3 spiral screw hose clamps - you'll know why after getting the old one out.

 

Quick thing to also check, is your heater hot, if not you are running cold and need to stop that ASAP cause your engine will also be running in OPEN LOOP, or what is called your cold start cycle and your gas mileages is going to go all to hell.

 

Update - Drive the vehicle around today, watching the temp gauge like a hawk. I am getting heat from the heater and now, after driving for a while, the temp seems to e back near the middle of the normal operating range. Going to keep watching and if it appears to act up again I am going to replace the thermostat. Decided to hold off spending any money until I got someone else's opinion.

 

Bleed that system well after installing the new t/stat.

 

A new thermostat is $15 with gasket, there could have been a piece of something stuck in it and it stuck open, could have been a loose temp sensor wire...

 

I'm going to do some investigating and probably replace the thermostat tomorrow. Thanks for the help.

 

Replace the thermostat..
I had the same sympoms you are describing and the thermostat fixed it right up, Heater gets hotter faster, temp stays in the middle on the highway.. All is well..