Its your thermostat. Mine did this same exact thing before it failed. My thermostat has been failed for 5 years now.
Temperature Fluctuations
- Thread starter Delta
- Start date
- Status
The temp sensor may not be in the same location as the thermostat. There may even be a sensor for the gauge and a separate one for the ECM.
I would say that wide of a temp fluxuation is a sign of a bad thermostat. Coasting down steep mountain grades in winter with ambient temperatures well into the negatives (your dash shows 37f) I don't see my temp fall at all once the engine is warm. When the temp falls in the engine, your fuel consumption goes up and it can be hard on the engine to have excess thermal cycles. A t-stat is cheap and generally easy to replace. Make sure you get the OEM temp. Going colder isn't beneficial.
I would say that wide of a temp fluxuation is a sign of a bad thermostat. Coasting down steep mountain grades in winter with ambient temperatures well into the negatives (your dash shows 37f) I don't see my temp fall at all once the engine is warm. When the temp falls in the engine, your fuel consumption goes up and it can be hard on the engine to have excess thermal cycles. A t-stat is cheap and generally easy to replace. Make sure you get the OEM temp. Going colder isn't beneficial.
Last edited:
Originally Posted By: Gannet167
A t-stat is cheap and generally easy to replace. Make sure you get the OEM temp. Going colder isn't beneficial.
Sounds easy except that on my car the intake manifold has to come off in order to even think about touching it.
A t-stat is cheap and generally easy to replace. Make sure you get the OEM temp. Going colder isn't beneficial.
Sounds easy except that on my car the intake manifold has to come off in order to even think about touching it.
Start the engine from cold.
As it sits and idles feel the top radiator hose.
It should stay cold until the engine gets up to operating temp.
If it gradually warms up it means your thermostat isn't closing, or it's opening too early.
As it sits and idles feel the top radiator hose.
It should stay cold until the engine gets up to operating temp.
If it gradually warms up it means your thermostat isn't closing, or it's opening too early.
Originally Posted By: circuitsmith
Start the engine from cold.
As it sits and idles feel the top radiator hose.
It should stay cold until the engine gets up to operating temp.
If it gradually warms up it means your thermostat isn't closing, or it's opening too early.
Did this today and the upper hose stayed cold till warmed up.
Start the engine from cold.
As it sits and idles feel the top radiator hose.
It should stay cold until the engine gets up to operating temp.
If it gradually warms up it means your thermostat isn't closing, or it's opening too early.
Did this today and the upper hose stayed cold till warmed up.
- Status
