Is my Thermostat good?
- Thread starter SwampSurvivor
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The threshold for coolant temperature on late model OBD2 vehicles is pretty stringent. If the PCM has not declared a problem, more than likely it is functioning as designed. It has been very cold here in the NE so i would not be surprised. I have not had good heat (HOT) until about 5 miles of drivng at 2 rpm lately.
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PO128 sets on most cars with three trips below 180 degrees. 3 good trips above 180 will also clear it. The time is about ten minutes or so. You would definitely set a code if there was any issue.
Depending on the car it can be very stringent, it even varies a bit on the same model.
Note also that almost any newer car has coolant flowing in the heater core all the time, with a door blocking/opening the airflow to the heated coolant as you demand cold or hot air.
Depending on the car it can be very stringent, it even varies a bit on the same model.
Note also that almost any newer car has coolant flowing in the heater core all the time, with a door blocking/opening the airflow to the heated coolant as you demand cold or hot air.
Just replaced my thermostat after 120K miles and it was stuck open. Had a p0126 though. Change it out.
Originally Posted By: SteveSRT8
PO128 sets on most cars with three trips below 180 degrees. 3 good trips above 180 will also clear it. The time is about ten minutes or so. You would definitely set a code if there was any issue.
Depending on the car it can be very stringent, it even varies a bit on the same model.
Note also that almost any newer car has coolant flowing in the heater core all the time, with a door blocking/opening the airflow to the heated coolant as you demand cold or hot air.
I have three Toyota products, with "manual climate control" Each has a heater control valve AND a door. The door only works at the extreme settings. I have known a number of cases where AC problems have been fixed by replacing the heater control valve which was leaking hot water through the heater core in the summer, door or no door. Automatic climate control works differently, it cools the air with the AC system even in cool weather and an auto heater control valve sets the temp of the then REHEATED air. That's why you hear compressers clattering away those cars even when it's 45 degrees out.
PO128 sets on most cars with three trips below 180 degrees. 3 good trips above 180 will also clear it. The time is about ten minutes or so. You would definitely set a code if there was any issue.
Depending on the car it can be very stringent, it even varies a bit on the same model.
Note also that almost any newer car has coolant flowing in the heater core all the time, with a door blocking/opening the airflow to the heated coolant as you demand cold or hot air.
I have three Toyota products, with "manual climate control" Each has a heater control valve AND a door. The door only works at the extreme settings. I have known a number of cases where AC problems have been fixed by replacing the heater control valve which was leaking hot water through the heater core in the summer, door or no door. Automatic climate control works differently, it cools the air with the AC system even in cool weather and an auto heater control valve sets the temp of the then REHEATED air. That's why you hear compressers clattering away those cars even when it's 45 degrees out.
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Indeed you may, but I have a lot more than 3 cars in my driveway including service vans, and every one of them works the way I described.
Only one of them has fancy climate control. I wish every car had manual control of the water flow as well as manual override on the compressor. We can dream...
Only one of them has fancy climate control. I wish every car had manual control of the water flow as well as manual override on the compressor. We can dream...
Originally Posted By: Miller88
So, I noticed that my 2011 Focus doesn't make heat very quickly in the winter. It's done it since new and a Ford dealer diag'd it as having a good thermostat and that it was normal for them to take a while making heat.
My current commute TO work, I pretty much coast the first mile, put along at 30 for the second mile, then the other 7 miles are highway at 45, then 55, then 65. On the colder mornings, it's not until I get almost to work that I have heat.
Unless I block the grille completely, the car doesn't get above 88C (thermostat is around 85C). Hottest day in the summer with the A/C on, the car doesn't go above 88C.
Driving at slow speeds with the engine completely cold, ambient temperature of 12, I drove it normally (which for me is very light) and the coolant wouldn't go above 77. I drove around for probably half an hour and the coolant was going between 70C and 77C.
I shut the car off and touched the radiator. Stone cold. I removed the rad cap and the coolant was also extremely cold. This would mean that the coolant didn't start circulating, right]/b].
I drove home, hopped on the interstate and went 65 and the car got up to 85C but as soon as I got off, it colled right back down. I shut it off and checked the radiator and it felt a little warmer than ambient and the coolant was somewhat warm too.
Popped the hood and let it sit for an hour off (temperature dropped to 9F) and did the same loop again, but instead I drove the car very hard ... not exceeding the speed limit. Driving it hard, the car heated up to 80F. I felt the radiator and it was a bit warmer than the first stop. Then I hopped on the highway, drove a bit faster, then drove hard (within the speed lmit) back to my apartment. The radiator was warm (didn't want to feel the coolant in case it was hot).
The fact that the radiator is staying cold would make one think that the thermostat is working?
I don't mind blocking off the grille, but my fear is forgetting and overheating it on a long highway trip in the winter
Sounds like the engine is very effective at dissipating heat. I doubt very much you have a problem,just block the grille.
If you can barely get it hot driving in the city then I doubt very much you will overheat on the highway.
So, I noticed that my 2011 Focus doesn't make heat very quickly in the winter. It's done it since new and a Ford dealer diag'd it as having a good thermostat and that it was normal for them to take a while making heat.
My current commute TO work, I pretty much coast the first mile, put along at 30 for the second mile, then the other 7 miles are highway at 45, then 55, then 65. On the colder mornings, it's not until I get almost to work that I have heat.
Unless I block the grille completely, the car doesn't get above 88C (thermostat is around 85C). Hottest day in the summer with the A/C on, the car doesn't go above 88C.
Driving at slow speeds with the engine completely cold, ambient temperature of 12, I drove it normally (which for me is very light) and the coolant wouldn't go above 77. I drove around for probably half an hour and the coolant was going between 70C and 77C.
I shut the car off and touched the radiator. Stone cold. I removed the rad cap and the coolant was also extremely cold. This would mean that the coolant didn't start circulating, right]/b].
I drove home, hopped on the interstate and went 65 and the car got up to 85C but as soon as I got off, it colled right back down. I shut it off and checked the radiator and it felt a little warmer than ambient and the coolant was somewhat warm too.
Popped the hood and let it sit for an hour off (temperature dropped to 9F) and did the same loop again, but instead I drove the car very hard ... not exceeding the speed limit. Driving it hard, the car heated up to 80F. I felt the radiator and it was a bit warmer than the first stop. Then I hopped on the highway, drove a bit faster, then drove hard (within the speed lmit) back to my apartment. The radiator was warm (didn't want to feel the coolant in case it was hot).
The fact that the radiator is staying cold would make one think that the thermostat is working?
I don't mind blocking off the grille, but my fear is forgetting and overheating it on a long highway trip in the winter
Sounds like the engine is very effective at dissipating heat. I doubt very much you have a problem,just block the grille.
If you can barely get it hot driving in the city then I doubt very much you will overheat on the highway.
Originally Posted By: SteveSRT8
Indeed you may, but I have a lot more than 3 cars in my driveway including service vans, and every one of them works the way I described.
Only one of them has fancy climate control. I wish every car had manual control of the water flow as well as manual override on the compressor. We can dream...
So, what is the control element in a "door" system?
Indeed you may, but I have a lot more than 3 cars in my driveway including service vans, and every one of them works the way I described.
Only one of them has fancy climate control. I wish every car had manual control of the water flow as well as manual override on the compressor. We can dream...
So, what is the control element in a "door" system?
There is only the blend door. The coolant flows is not restricted through the heater core. The door simply blocks or mixes the hot side into the cool side to give the desired temp.
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