# 2007 Altima - How many coolant thermostats are there?



## Ronin_wars (Apr 20, 2016)

Hello guys! I just recently received a P0128 error code on my 2007 Nissan Altima 2.5S and was wondering how many coolant thermostats are there? Nissan tells me, there is one but I have seen schematics showing there is two. I recently had my car serviced at a Nissan dealership and they have replaced one thermostat and re-filled coolant. However, a week and half later, the SES light came back and code P0128 was again detected.


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## SPEEDO (Jun 9, 2003)

the thermostat is on the side of the engine, there is what they call a "water control valve" (which looks like a thermostat) on the back of the engine... if that helps


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## Ronin_wars (Apr 20, 2016)

Thanks Speedo. Would that need be replaced as well for a P0128 considering that it's for the water pump? I would imagine the primary would be the coolant thermostat.


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## OhmsLaw (Mar 29, 2016)

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## rogoman (Dec 16, 2004)

Ronin_wars said:


> Would that need be replaced as well for a P0128 considering that it's for the water pump? I would imagine the primary would be the coolant thermostat.


There are two thermostats. The main one feeds the radiator. The second one is called a water control valve which feeds several accessories such as the heater and oil cooler; it's purpose is quicker warmup for the accessories. If it's stuck closed, it could possibly cause overheating.


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## cj1 (Oct 21, 2014)

Misdiagnoses? If P0128 was what the repair was intended to fix then return to dealer for a redo. ECT sensor maybe miscalibrated.


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## Ronin_wars (Apr 20, 2016)

@rogoman- Thank you. Had no driveability or overheating issues since the engine light and code came up. But that second sensor by water control valve maybe a culprit The only thing that was changed by me was the Coolant sensor @cj1 it was an aftermarket part. A mis-calibration is something for Nissan to check as well. Thank you both!


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