Overheating Problem
11-04-2010, 06:29 AM
#1
Overheating Problem
For whatever reason my truck is starting to overheat. The weird thing about it is that it only happens when the heat is on. I can run all day in 100* weather and the temp will stay the same, but when its cold out and i need the heat the temp skyrockets! It almost hits the "red zone" on the temp gauge! To get it to cool down i need to slide the knob from heat to cold and turn off the blower. There is sufficient coolant in the radiator, the heat all works fine, I'm thinking maybe it's the thermostat? Not too sure. Heater coil? Any ideas?
11-04-2010, 06:43 AM
#2
Registered User
typical temperature overshoot problem.
http://www.4crawler.com/4x4/CheapTri...tml#Thermostat
I fixed mine by drilling that small hole in the thermostat. Takes a little longer to heat up the engine but that could be cause I have the heater control valve completely bypassed as well.
http://www.4crawler.com/4x4/CheapTri...tml#Thermostat
I fixed mine by drilling that small hole in the thermostat. Takes a little longer to heat up the engine but that could be cause I have the heater control valve completely bypassed as well.
Last edited by xxxtreme22r; 11-04-2010 at 06:44 AM.
11-04-2010, 06:48 AM
#4
Registered User
isn't the stock temp on these 190? Because there is a coolant temp sensor on these running anything cooler than that can have adverse effects on the EFI system. Carb'd trucks might get away with running a cooler thermo though since nothing other than vacuum controls the ignition timing.
Last edited by xxxtreme22r; 11-04-2010 at 06:50 AM.
11-04-2010, 06:55 AM
#5
isn't the stock temp on these 190? Because there is a coolant temp sensor on these running anything cooler than that can have adverse effects on the EFI system. Carb'd trucks might get away with running a cooler thermo though since nothing other than vacuum controls the ignition timing.
11-04-2010, 07:21 AM
#6
Registered User
the cooler t-stat seems to be a big debate, some say it helps with pinging other say the thing runs better with a 190-195 t-stat in.
but I really don't think your problem is the t-stat and that the cooler t-stat will help mask the overshoot problem but you will still see it without either the dual stage t-stat or drilling that hole.
the overshoot problem is actually because the heater dumps it's cooled coolant basically into the t-stat housing fooling the thermostat into staying closed. Basically causing a sticking t-stat. Essentially causing a hot pocket of coolant in the engine which is why the temp gauge spikes when that pocket hits the gauge sensor. Once it goes by the gauge returns to normal.
With the cooler t-stat the temp swing wont be as big but the problem still exists. The hole in the t-stat helps keep the fluid moving across the t-stat, keeping the cooler heater core fluid from keeping the thermostat close longer than it should be.
Another side effect of using the cooler t-stat would be a less efficient heater. Which is also a side effect of drilling that hole in the t-stat as well. Just not sure how much each will affect heater operation. In mine the heater works pretty well considering I got a 190 in mine with the hole drilled.
but I really don't think your problem is the t-stat and that the cooler t-stat will help mask the overshoot problem but you will still see it without either the dual stage t-stat or drilling that hole.
the overshoot problem is actually because the heater dumps it's cooled coolant basically into the t-stat housing fooling the thermostat into staying closed. Basically causing a sticking t-stat. Essentially causing a hot pocket of coolant in the engine which is why the temp gauge spikes when that pocket hits the gauge sensor. Once it goes by the gauge returns to normal.
With the cooler t-stat the temp swing wont be as big but the problem still exists. The hole in the t-stat helps keep the fluid moving across the t-stat, keeping the cooler heater core fluid from keeping the thermostat close longer than it should be.
Another side effect of using the cooler t-stat would be a less efficient heater. Which is also a side effect of drilling that hole in the t-stat as well. Just not sure how much each will affect heater operation. In mine the heater works pretty well considering I got a 190 in mine with the hole drilled.
Last edited by xxxtreme22r; 11-04-2010 at 07:24 AM.
11-04-2010, 07:33 AM
#7
the cooler t-stat seems to be a big debate, some say it helps with pinging other say the thing runs better with a 190-195 t-stat in.
but I really don't think your problem is the t-stat and that the cooler t-stat will help mask the overshoot problem but you will still see it without either the dual stage t-stat or drilling that hole.
the overshoot problem is actually because the heater dumps it's cooled coolant basically into the t-stat housing fooling the thermostat into staying closed. Basically causing a sticking t-stat. Essentially causing a hot pocket of coolant in the engine which is why the temp gauge spikes when that pocket hits the gauge sensor. Once it goes by the gauge returns to normal.
With the cooler t-stat the temp swing wont be as big but the problem still exists. The hole in the t-stat helps keep the fluid moving across the t-stat, keeping the cooler heater core fluid from keeping the thermostat close longer than it should be.
Another side effect of using the cooler t-stat would be a less efficient heater. Which is also a side effect of drilling that hole in the t-stat as well. Just not sure how much each will affect heater operation. In mine the heater works pretty well considering I got a 190 in mine with the hole drilled.
but I really don't think your problem is the t-stat and that the cooler t-stat will help mask the overshoot problem but you will still see it without either the dual stage t-stat or drilling that hole.
the overshoot problem is actually because the heater dumps it's cooled coolant basically into the t-stat housing fooling the thermostat into staying closed. Basically causing a sticking t-stat. Essentially causing a hot pocket of coolant in the engine which is why the temp gauge spikes when that pocket hits the gauge sensor. Once it goes by the gauge returns to normal.
With the cooler t-stat the temp swing wont be as big but the problem still exists. The hole in the t-stat helps keep the fluid moving across the t-stat, keeping the cooler heater core fluid from keeping the thermostat close longer than it should be.
Another side effect of using the cooler t-stat would be a less efficient heater. Which is also a side effect of drilling that hole in the t-stat as well. Just not sure how much each will affect heater operation. In mine the heater works pretty well considering I got a 190 in mine with the hole drilled.
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11-04-2010, 07:41 AM
#11
Registered User
follow the 4crawlers suggestions. but try the new one first before drilling the hole, it might just work out for ya. who knows.
if you do drill the hole, don't go any bigger than 1/16" and it gets drill in the base where the little jiggle valve is. Some say removing the little jiggle valve if the t-stat has one works too, some aftermarket ones do some don't. I don't know exactly what that jiggle valve does so I left mine in and drilled the 1/16" hole next to it. The dual stage t-stat from toyota has one and the single stage does not.
if you do drill the hole, don't go any bigger than 1/16" and it gets drill in the base where the little jiggle valve is. Some say removing the little jiggle valve if the t-stat has one works too, some aftermarket ones do some don't. I don't know exactly what that jiggle valve does so I left mine in and drilled the 1/16" hole next to it. The dual stage t-stat from toyota has one and the single stage does not.
11-04-2010, 09:19 AM
#13
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I drilled a hole that's about 1/8th inch in diameter. Now the overheating problem is fixed, but the temp gauge needle only goes about a quarter of the way over instead of a third of the way over like it used to. So don't drill the hole too big around like I did.
11-08-2010, 08:37 AM
#15
Registered User
razed your looking at it the wrong way. when the coolant comes out of the heater core it's cooled down and dumps into inlet of the water pump yes, but that cooled coolant them goes straight to the thermostat fooling the thermostat of it's true coolant temp not letting it open when it should. This is why Toyota developed the dual stage thermostat because they knew it was a design flaw.
If he had problems cooling the motor without the heater on then I would say it's a problem within the cooling system.
Most of us on here know about the temperature overshoot problem and the related Toyota TSB on it. Which is supposedly only have affected early 22re's but it affects most of us.
If he had problems cooling the motor without the heater on then I would say it's a problem within the cooling system.
Most of us on here know about the temperature overshoot problem and the related Toyota TSB on it. Which is supposedly only have affected early 22re's but it affects most of us.
11-08-2010, 08:47 AM
#16
Registered User
tell me this if you add an equal amount of 100 degree water to 200 degree water what happens to the temp of that water? it's no longer 200 degree water like the rest of the system in the coolant line that should have opened the thermostat. You are dumping cooler water to the hot side of the thermostat plain and simple do you really thing the thermostat is gonna open when it should? no. And when it finally does and that hot side coolant that was just sitting there waiting for the thermostat to open goes past the temp sender for the gauge this is why it spikes because that coolant is really that hot at that moment.
Last edited by xxxtreme22r; 11-08-2010 at 08:51 AM.
11-08-2010, 08:53 AM
#17
Registered User
"What happens on the 22R and 22RE engine, when the coolant goes through the heater core it gets cooled off enough that when it gets dumped back in on top of the t-stat it shuts it. Therefore the temperature in the engine continues to go up"
11-08-2010, 08:56 AM
#18
Registered User
every single motor on the planet as far as I know the water pump is before the thermostat. and if your sending to the inlet of the water pump cooler water than what is in the engine you are sending cooler water than is in the engine into the thermostat.
I don;t think your understanding why Toyota developed the dual stage thermostat because people have had problems cooling the 22re with the heater on. Like Brian.
If your theory is correct and his problem is in the main cooling system then turning the heater on would allow him to too cool the engine more not make it run hotter.
I don;t think your understanding why Toyota developed the dual stage thermostat because people have had problems cooling the 22re with the heater on. Like Brian.
If your theory is correct and his problem is in the main cooling system then turning the heater on would allow him to too cool the engine more not make it run hotter.
Last edited by xxxtreme22r; 11-08-2010 at 08:59 AM.
11-08-2010, 09:37 AM
#19
Registered User
doesn't heater flow go to and from the timing cover? where the heater is essentially a bypass of the entire motor? Sorry my brain's not working right today it seems too much stuff going on haha.
Last edited by xxxtreme22r; 11-08-2010 at 09:39 AM.
