Engine runs cold but heater works fine. Bad thermostat or something else?

[303george]

Got a CEL the other day. I checked it at a parts store and cleared the code. I had the code written down but now I can't find the scrap of paper I had it written on. I do remember that it said that the coolant was too cold.

Anyway, I've noticed since then that the heat guage is pretty much always just past the second line on the cold side. My heater works perfectly fine though. I usually let the truck run for about 5 to 10 min before leaving for work and it's always blowing warm air by then. I drive for about another 10 minutes to work but the engine never heats up fully.

Does this sound like a bad thermostat? Should I replace it or just wait and see if the CEL comes back on?

[modelageek]

Originally Posted by 303george

Got a CEL the other day. I checked it at a parts store and cleared the code. I had the code written down but now I can't find the scrap of paper I had it written on. I do remember that it said that the coolant was too cold.

Anyway, I've noticed since then that the heat guage is pretty much always just past the second line on the cold side. My heater works perfectly fine though. I usually let the truck run for about 5 to 10 min before leaving for work and it's always blowing warm air by then. I drive for about another 10 minutes to work but the engine never heats up fully.

Does this sound like a bad thermostat? Should I replace it or just wait and see if the CEL comes back on?

You need the CEL to do it right! that being said if the stat is old you could change it as a maintenance item.

[CBRXLT]

Had the same type issue two weeks ago. Cleared code twice, then finally took it in. Thermostat was the culprit.


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[303george]

In case anyone runs in to the same issue, it turned out to be the thermostat. I went ahead and swapped it out and the CEL shut off on it's own a few days later.