lillywerner98
Allion Overheating Map Thermostat Suspected
Summary of the thread
A 2023 Toyota Allion hybrid was experiencing engine overheating and delayed warming up, despite no coolant leaks and a functioning cooling fan. The issue was suspected to be related to the map thermostat. A suggestion was made to check the thermostat, as a defective one could cause these symptoms. After visiting a workshop, it was confirmed that the map thermostat was indeed the problem, and replacing it resolved the issue.
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4 comment(s)
lillywerner98 (community.author)
The temperature gauge stays pretty high once it eventually warms up. Where is the map thermostat located, and is it easy to check or replace?
gerhardtiger10
On my Allion, the map thermostat was integrated into the thermostat housing. While you could technically check its electrical connections, given your symptoms, a defective motor within the thermostat cooling circuit is highly probable. In my experience, it is usually the case. I would recommend getting it checked by a workshop to confirm and avoid potential further damage.
lillywerner98 (community.author)
I took it to a workshop, and you were right it was the map thermostat. The replacement cost around 350€. Engine is running fine now. Appreciate the help!
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TOYOTA
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ALLION
gerhardtiger10
I had a similar problem with my Allion. Does the temperature gauge fluctuate a lot, or stay consistently high? Have you checked the temperature sensor? It might be worth looking into the map thermostat; a defective one can cause those exact symptoms.