overheating when using heater only?
#1
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22re overheating when using heater only?
Hi
Heres a 22re question for the gurus. I went wheeling last weekend and as I was coming down from the mountain, I turned on the heater. Shortly afterward, the temp gauge started cycling from near overheating to normal, and it did that up/down thing almost exactly once a minute for about 100 miles. When I got back to sacramento, I turned the heater off and the temp was rock solid at 50%. Any ideas what could be causing the engine to overheat only when the heater is on? I was thinking that I was losing coolant, but the rad is topped off and there is about 20% left in the overflow.
Anyone heard of anything like this before?
Heres a 22re question for the gurus. I went wheeling last weekend and as I was coming down from the mountain, I turned on the heater. Shortly afterward, the temp gauge started cycling from near overheating to normal, and it did that up/down thing almost exactly once a minute for about 100 miles. When I got back to sacramento, I turned the heater off and the temp was rock solid at 50%. Any ideas what could be causing the engine to overheat only when the heater is on? I was thinking that I was losing coolant, but the rad is topped off and there is about 20% left in the overflow.
Anyone heard of anything like this before?
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#4
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This is kind of a neat problem (at least in my mind)....what happens is, the engine gets hot, the thermostat opens letting coolant flow into the radiator to be cooled where it then flows back around the engine picking up more of the engine heat and the cycle continues over and over again.
Now you go and turn on the heat letting coolant flow into the heater core. There, it's cooled by your blower...then the coolant drops in temperature and flows back to the thermostat closing it preventing the rest of the coolant from flowing so the engine temperature goes up up up until the pool of fluid near the thermostat finally reaches the temperature to open it up again.
The same kind of thing happens in my house. If you turn the heat on and close all of the doors, the heat stays on forever because the doors prevent the thermostat from ever seeing the heat that the furnace is dumping into the rooms. You need to have circulation and that's what a dual stage t-stat in your car gets you.
Now you go and turn on the heat letting coolant flow into the heater core. There, it's cooled by your blower...then the coolant drops in temperature and flows back to the thermostat closing it preventing the rest of the coolant from flowing so the engine temperature goes up up up until the pool of fluid near the thermostat finally reaches the temperature to open it up again.
The same kind of thing happens in my house. If you turn the heat on and close all of the doors, the heat stays on forever because the doors prevent the thermostat from ever seeing the heat that the furnace is dumping into the rooms. You need to have circulation and that's what a dual stage t-stat in your car gets you.
#5
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Hi
Heres a 22re question for the gurus. I went wheeling last weekend and as I was coming down from the mountain, I turned on the heater. Shortly afterward, the temp gauge started cycling from near overheating to normal, and it did that up/down thing almost exactly once a minute for about 100 miles. When I got back to sacramento, I turned the heater off and the temp was rock solid at 50%. Any ideas what could be causing the engine to overheat only when the heater is on? I was thinking that I was losing coolant, but the rad is topped off and there is about 20% left in the overflow.
Anyone heard of anything like this before?
Heres a 22re question for the gurus. I went wheeling last weekend and as I was coming down from the mountain, I turned on the heater. Shortly afterward, the temp gauge started cycling from near overheating to normal, and it did that up/down thing almost exactly once a minute for about 100 miles. When I got back to sacramento, I turned the heater off and the temp was rock solid at 50%. Any ideas what could be causing the engine to overheat only when the heater is on? I was thinking that I was losing coolant, but the rad is topped off and there is about 20% left in the overflow.
Anyone heard of anything like this before?
edit--- My gut feeling is if the cooling system is that finicky with just putting the heater on that a bigger main issue is behind it...and I'm thinking new radiator. .....a brand new one and not the rodded out ones that don't seem to be 100% there. That's just my gut speaking though.
Last edited by ZUK; 07-08-2011 at 07:36 AM. Reason: after-thought
#7
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oh by the way what did you have to add other than this to the thread????
also diffdog search for temp over shoot and look through 4crawlers site regarding your issue. i think he has the part numbers for the dual stage t-stat as well.
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#8
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The part number for the dual-stage thermostat is 90916-03070
I see the issue mostly happening on the 4-runners with the rear heater.
Cures the problem every time.
Keep us posted.
I see the issue mostly happening on the 4-runners with the rear heater.
Cures the problem every time.
Keep us posted.
Hi
Heres a 22re question for the gurus. I went wheeling last weekend and as I was coming down from the mountain, I turned on the heater. Shortly afterward, the temp gauge started cycling from near overheating to normal, and it did that up/down thing almost exactly once a minute for about 100 miles. When I got back to sacramento, I turned the heater off and the temp was rock solid at 50%. Any ideas what could be causing the engine to overheat only when the heater is on? I was thinking that I was losing coolant, but the rad is topped off and there is about 20% left in the overflow.
Anyone heard of anything like this before?
Heres a 22re question for the gurus. I went wheeling last weekend and as I was coming down from the mountain, I turned on the heater. Shortly afterward, the temp gauge started cycling from near overheating to normal, and it did that up/down thing almost exactly once a minute for about 100 miles. When I got back to sacramento, I turned the heater off and the temp was rock solid at 50%. Any ideas what could be causing the engine to overheat only when the heater is on? I was thinking that I was losing coolant, but the rad is topped off and there is about 20% left in the overflow.
Anyone heard of anything like this before?
Last edited by putneysmachine; 07-15-2011 at 10:00 AM. Reason: gave the wrong part #. ok now.(sorry)
#9
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Good reading below...this is exactly what's happening to yours.
http://www.4crawler.com/4x4/CheapTri...tml#Thermostat
http://www.4crawler.com/4x4/CheapTri...tml#Thermostat
#10
I like the idea of the dual thermostat! I'll have to try it because my truck does the same thing in the winter when I use the heat.
I have a possible alternative solution, although it edges on the ghetto side. I used to have an '87 Voyager that would overheat because the thermostat would never open. Turns out air was being trapped under the thermostat, keeping it from heating up and opening. My solution was to drill a 3/16" hole in the thermostat to allow water to pass even when it was closed. Maybe this would work for the yotas also...
I have a possible alternative solution, although it edges on the ghetto side. I used to have an '87 Voyager that would overheat because the thermostat would never open. Turns out air was being trapped under the thermostat, keeping it from heating up and opening. My solution was to drill a 3/16" hole in the thermostat to allow water to pass even when it was closed. Maybe this would work for the yotas also...
#11
Registered User
I like the idea of the dual thermostat! I'll have to try it because my truck does the same thing in the winter when I use the heat.
I have a possible alternative solution, although it edges on the ghetto side. I used to have an '87 Voyager that would overheat because the thermostat would never open. Turns out air was being trapped under the thermostat, keeping it from heating up and opening. My solution was to drill a 3/16" hole in the thermostat to allow water to pass even when it was closed. Maybe this would work for the yotas also...
I have a possible alternative solution, although it edges on the ghetto side. I used to have an '87 Voyager that would overheat because the thermostat would never open. Turns out air was being trapped under the thermostat, keeping it from heating up and opening. My solution was to drill a 3/16" hole in the thermostat to allow water to pass even when it was closed. Maybe this would work for the yotas also...
The only downfall to drilling a hole is it takes the motor longer to warm up. In warmer climates one can get away with it, however in Wyoming you want a quicker warm up period.
How I know you ask?...
I've tried it and the motor just ran too cold in the winter. 22RE's like a warmer setting to acheive the most efficient combustion cycle.
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Haha it is pretty clever...that's why it's common! Most guys only drill about a 1/16" or 3/32" hole to prevent too much coolant from bypassing the thermostat though. I drilled a 1/16" hole in mine and when it gets below about 15 degrees I have to put cardboard in front of the radiator, otherwise I can drive all day and never see a reading on the temp gauge.
#14
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Thread Starter
Ill try the dual stage thermostat first. Funny thing is that the truck didn't used to do this until recently. Before last month it was working fine even with the heater on.
#15
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Don't feel bad, cooling systems can be finicky beasts.
I ran into the same problem only after installing a new engine for a customer (along with a OEM t-stat), the problem didn't show up until after I did his first oil change. Even then it only showed up when driving DOWNHILL instead of on the 6 mile uphill drive).
Go figure.
I ran into the same problem only after installing a new engine for a customer (along with a OEM t-stat), the problem didn't show up until after I did his first oil change. Even then it only showed up when driving DOWNHILL instead of on the 6 mile uphill drive).
Go figure.
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