overheating when the heater is on
11-29-2010, 07:37 PM
#1
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overheating when the heater is on
i bought a toyota pick up...single cab,22re,stick shift,
and everything was fine until i turn on the heater...
as soon a turn it on the truck starts getting hot,(weird)
it looks like it sucks the watwer out of the sistem,cause the reservoir gets MT.and when i turn it off,like magic,the water goes back into the little can...
please help me!!!!!!!!!!!!!!
out off ideas
and everything was fine until i turn on the heater...
as soon a turn it on the truck starts getting hot,(weird)
it looks like it sucks the watwer out of the sistem,cause the reservoir gets MT.and when i turn it off,like magic,the water goes back into the little can...
please help me!!!!!!!!!!!!!!
out off ideas
11-30-2010, 10:31 AM
#6
i've never had the problem and have an autozone single stage stat. so to me if you need that stat somethign else is the problem.
my exp, and from searching the web all say radiator / hose prob. its easy to see when you see how the coolant flows in the system. the heater and radiator / tstat are parallel systems and the heater core returns coolant to the inlet of the water pump NOT by the t-stat.
oh well
my exp, and from searching the web all say radiator / hose prob. its easy to see when you see how the coolant flows in the system. the heater and radiator / tstat are parallel systems and the heater core returns coolant to the inlet of the water pump NOT by the t-stat.
oh well
11-30-2010, 10:56 AM
#7
That is 100% true, I did not believe it until it happened to my engine. The small valve on that t-stat responds faster to temperature changes than the large valve (basic thermodynamics). I think the main cause of the temp. overshoot issue is some sort of coolant flow instability in/around the head. Normally it is all fine, but make one tiny internal change and the flow gets unstable and the problem pops up. And if you have not seen that problem before, it is really not something that looks like normal overheating. The temp gauge will just pop from normal to the red mark in a few seconds, in my case with the heater valve open. With the heater valve closed, it never did that. And what does that say? Opening the heater valve makes a tiny change in the coolant flow in/around the head. And upon closing the heater valve with the temps in the red the needle drops in a few seconds. In the real world, there is no way you could cause the coolant in the entire engine to cool down that far that fast.
And if the problem did not exist, why would Toyota have issued a TSB (Tech Service Bulletin) and developed that special t-stat to solve it:
And if the problem did not exist, why would Toyota have issued a TSB (Tech Service Bulletin) and developed that special t-stat to solve it:
TSB: 029032787 22R-E Engine Temperature Overshoot
It says:
Some 1984 pickup trucks and 1983-1984 Celica models, equipped with 22R-E engines, may experience a condition called "temperature gauge overshoot". After starting a cold engine the temperature gauge will indicate a higher than normal engine temperature for a short time just prior to the thermostat opening. After the thermostat opens, the temperature gauge will return to the normal range. A new double valve thermostat has been made available to reduce temperature gauge overshoot.
And calls for part number 90916-03070 which according to the TSB replaces 90916-03055.
It says:
Some 1984 pickup trucks and 1983-1984 Celica models, equipped with 22R-E engines, may experience a condition called "temperature gauge overshoot". After starting a cold engine the temperature gauge will indicate a higher than normal engine temperature for a short time just prior to the thermostat opening. After the thermostat opens, the temperature gauge will return to the normal range. A new double valve thermostat has been made available to reduce temperature gauge overshoot.
And calls for part number 90916-03070 which according to the TSB replaces 90916-03055.
Last edited by 4Crawler; 11-30-2010 at 10:58 AM.
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11-30-2010, 11:12 AM
#8
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I agree with 4crawler, I did not have that problem till I completly rebuilt my motor (new head, new water pump, new hoses btw). I originally thought it was a bad brand new thermostat (autozone) in mine, replaced it with the old one that came out of the "original" motor and it was still there. So I drilled the hole in the new t-stat as 4crawler mentions, no problems since then.
Last edited by xxxtreme22r; 11-30-2010 at 11:14 AM.
11-30-2010, 11:48 AM
#9
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One was that when the heater is on that somehow between 2 and 3 cyls the coolant sits still heating it up to where it spikes the temp gauge.
That whole thing still has me confused haha.
11-30-2010, 12:20 PM
#10
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I agree with 4crawler, I did not have that problem till I completly rebuilt my motor (new head, new water pump, new hoses btw). I originally thought it was a bad brand new thermostat (autozone) in mine, replaced it with the old one that came out of the "original" motor and it was still there. So I drilled the hole in the new t-stat as 4crawler mentions, no problems since then.
that's enough proof for me that this overshoot problem is not one of a problem with something else and does not need a dual stage which only "masks" another problem. if that's what your talking about.
11-30-2010, 02:20 PM
#14
Registered User
4crawler already posted it. 
That is 100% true, I did not believe it until it happened to my engine. The small valve on that t-stat responds faster to temperature changes than the large valve (basic thermodynamics). I think the main cause of the temp. overshoot issue is some sort of coolant flow instability in/around the head. Normally it is all fine, but make one tiny internal change and the flow gets unstable and the problem pops up. And if you have not seen that problem before, it is really not something that looks like normal overheating. The temp gauge will just pop from normal to the red mark in a few seconds, in my case with the heater valve open. With the heater valve closed, it never did that. And what does that say? Opening the heater valve makes a tiny change in the coolant flow in/around the head. And upon closing the heater valve with the temps in the red the needle drops in a few seconds. In the real world, there is no way you could cause the coolant in the entire engine to cool down that far that fast.
And if the problem did not exist, why would Toyota have issued a TSB (Tech Service Bulletin) and developed that special t-stat to solve it:
And if the problem did not exist, why would Toyota have issued a TSB (Tech Service Bulletin) and developed that special t-stat to solve it:
TSB: 029032787 22R-E Engine Temperature Overshoot
It says:
Some 1984 pickup trucks and 1983-1984 Celica models, equipped with 22R-E engines, may experience a condition called "temperature gauge overshoot". After starting a cold engine the temperature gauge will indicate a higher than normal engine temperature for a short time just prior to the thermostat opening. After the thermostat opens, the temperature gauge will return to the normal range. A new double valve thermostat has been made available to reduce temperature gauge overshoot.
And calls for part number 90916-03070 which according to the TSB replaces 90916-03055.
It says:
Some 1984 pickup trucks and 1983-1984 Celica models, equipped with 22R-E engines, may experience a condition called "temperature gauge overshoot". After starting a cold engine the temperature gauge will indicate a higher than normal engine temperature for a short time just prior to the thermostat opening. After the thermostat opens, the temperature gauge will return to the normal range. A new double valve thermostat has been made available to reduce temperature gauge overshoot.
And calls for part number 90916-03070 which according to the TSB replaces 90916-03055.
Last edited by xxxtreme22r; 11-30-2010 at 02:22 PM.
11-30-2010, 02:46 PM
#17
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depends on how he words his symptoms, first thing 4crawler told him was to see if the overshoot symptoms applied. We all know how some people are around here saying what they don't mean and not fully describing what is really going on etc etc.
Question is, is this thing running hot or is the temp gauge just spiking like described in 4crawlers write up.
the O.P. seems to confirm by reading 4crawlers writeup on the ovesrshoot that his symptoms matched the overshoot problem and nothing else.
Question is, is this thing running hot or is the temp gauge just spiking like described in 4crawlers write up.
the O.P. seems to confirm by reading 4crawlers writeup on the ovesrshoot that his symptoms matched the overshoot problem and nothing else.
11-30-2010, 02:56 PM
#18
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It's finally Winter in AZ and I am having this very problem with my 89. I have the single stage thermostat. The dual stage is the fix I'm told by the local dealer. For now what I have been doing is letting the engine reach normal operating temp then put the slider on heat and all is fine. On especially cold mornings (running late for work) slide it to the hot side, allowing rapid engine heat to build. When the temp gets where you want it, slide to the cold side and give it 1 min. The temp will go back to normal and you can put the heat back on without temp overshoot. It's kind of a cool feature once you lean how to use it. Really speeds up heating time.
12-02-2010, 06:14 PM
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sorry.but i have been working 'till gets dark ,and on top of dat.traffic (so.cal 405),sucks
but here is the update.
bought the double valve, t-stat(90916-03070)and the problem got better..
now i am riding with the heater on ,and the temp just go up to 3/4
i am going to change all the hoses,in the sistem saturday.radiator and heater.
but here is the update.
bought the double valve, t-stat(90916-03070)and the problem got better..
now i am riding with the heater on ,and the temp just go up to 3/4
i am going to change all the hoses,in the sistem saturday.radiator and heater.
Last edited by tacho75; 12-02-2010 at 06:16 PM.
12-06-2010, 03:06 PM
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Well I'm about to get into a similar thing. My truck didn't seem to be heating up enough so I replaced my 180 degree thermostat with a 195 made by Stant (I know I know...dealership was closed...) It would spike up pretty high on startup and then settle to just under half on the temp gauge. Figured I had the overshoot problem, bought the dual stage, and the problem lessened but is definitely not fixed. So, next time I got the truck up to temp I touched the lower hose and go figure it was barely warm. So, clearly I have a clogged radiator, and it was sort of mimicking the overshoot issue. I will be attempting to clean out the rad tomorrow and if that doesn't work I'll put a new one in. I'll post up my results here.
