How cool is too cool?
TECH Senior Member
Joined: Apr 2002
Posts: 6,080
Likes: 17
From: So.Cal.
I'm consistently seeing P0128 (and absurdly low running temperature) on a 2002 GAGT 3.4L LA1, it has a closed system (so both issue and curious).
Thanks.
Last edited by joecar; Mar 5, 2014 at 12:28 PM.
TECH Senior Member
Joined: Apr 2002
Posts: 6,080
Likes: 17
From: So.Cal.
[ Also, I saw today the surge tank has an otherwise invisible hairline crack at the top... this is so much fun... ]
Russ Kemp
Thread Starter
TECH Addict
iTrader: (17)
Joined: Sep 2012
Posts: 2,670
Likes: 38
From: Westchester, NY
I am no mechanic, but I'll throw my logic your way. See if it makes sense.
The car is running cool (and we are assuming that this is true and that you dont have a bad sensor - does the car produce good, hot heat?) because too much coolant is being allowed to flow through the rad and back into the motor before it has a chance to warm up. There are two possible places this could happen. 1 - The thermostat if it is stuck open. 2 - The bypass hose from the surge tank to the water pump. Assuming that this is correct, and since you said it looked like the tank was replaced, I think it makes more sense to rule out number 2 first. It seems not only more likely that the problem is here but also easier to check than getting to the thermostat.
Alluding to what another member mentioned here..... Can you see through the surge tank? I recall now (yes I saw this and thought nothing of it months ago) being able to see a lot of coolant flowing into the surge tank coming from the line connected to the rad. In hind sight it was like A LOT!!! If you can't see though it you could always just pop the line off of the surge tank and have someone start the car. If coolant comes pouring out then I would think that that is your problem.
The car is running cool (and we are assuming that this is true and that you dont have a bad sensor - does the car produce good, hot heat?) because too much coolant is being allowed to flow through the rad and back into the motor before it has a chance to warm up. There are two possible places this could happen. 1 - The thermostat if it is stuck open. 2 - The bypass hose from the surge tank to the water pump. Assuming that this is correct, and since you said it looked like the tank was replaced, I think it makes more sense to rule out number 2 first. It seems not only more likely that the problem is here but also easier to check than getting to the thermostat.
Alluding to what another member mentioned here..... Can you see through the surge tank? I recall now (yes I saw this and thought nothing of it months ago) being able to see a lot of coolant flowing into the surge tank coming from the line connected to the rad. In hind sight it was like A LOT!!! If you can't see though it you could always just pop the line off of the surge tank and have someone start the car. If coolant comes pouring out then I would think that that is your problem.
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