P0128 code

JeepJeep

New Member
Joined
Nov 4, 2019
Messages
5
Location
USA
Hi all. Im new to this site and just wanted to get other opinions. My check engine light came on so I got my code reader and it threw "P0128". I just recently replaced my thermostat in the last couple months so I'm not sure what this new code is for. Any help?!
 
What kind of thermostat did you replace it with? Hopefully not a low temp one.

It sounds like your vehicle is leaking or burning coolant. Have you checked the coolant level in the radiator when the engine is cold?
 
What kind of thermostat did you replace it with? Hopefully not a low temp one.

It sounds like your vehicle is leaking or burning coolant. Have you checked the coolant level in the radiator when the engine is cold?
Im sorry i didn't see your response. I'm not exactly sure what type of thermostat it was but it was a higher temperature one. I brought it into a mechanic and he held onto it for a couple days but when i got it back he said he wasnt able to find anything. My check engine lught came back on again and my coolant level is still dropping (not nearly as much as it was but still dropping).
 
Im sorry i didn't see your response. I'm not exactly sure what type of thermostat it was but it was a higher temperature one. I brought it into a mechanic and he held onto it for a couple days but when i got it back he said he wasnt able to find anything. My check engine lught came back on again and my coolant level is still dropping (not nearly as much as it was but still dropping).

It sounds like you may have a cracked head / block. Either that or possibly a head gasket that is going bad.
 
Try to run it at a high idle in the highway until the temp goes full hot then pull in the side and shot the engine off and open the hood and observe how the engine cools down. The reservoir fluid should already be at full level (not empty) and if not, you have a bigger problem.
 
Last edited:
Yeah i know. I took it to a mechanic and he said he did something to check the head gasket and said it wasn't it.
 
Check your oil. If it's 'milky', there's your coolant. If it's dropping that fast, I would expect to see it in oil or the exhaust, if it's straight burning it.

When you changed the thermostat, did you drain the coolant? If so, are you sure all of the air is out of the system? Are you sure you put enough back in?

Just my 2 pennies.

Tim
 
  • Like
Reactions: Chris
The Rickety 2008 is back!!

I literally just changed the thermostat last summer. Been reading the other threads on this, could be the sensor too? Guess I don't in changing it again since it's Not a big deal but maybe people know a good thermostat ? She got to 20.9 mpg by the way 🤣 could she be running too efficiently?

Screenshot_20230303-182038_OBD JScan.jpg


Screenshot_20230303-182058_OBD JScan.jpg


Screenshot_20230303-182109_OBD JScan.jpg