Lee
07-11-2007, 12:21 PM
I have had intermittent overheating issues and I believe I have totally solved them. If you are having these issues, this thread will document and inform you of what I have learned. These are my experiences and opinions, what is documented here is intended to help you inspect and determine your issues or guide you through the process of narrowing what is causing your engine to run warm.
Step 1: Coolant
Are you using Toyota coolant? If not, flush your system and refill with genuine Toyota coolant. What I did for this was to unhook the upper and lower hoses on the radiator and drained the coolant into a bucket. Be sure to dispose of the coolant at an authorized local dump, do not dispose of it irresponsibly. Next, with the engine running and radiator hoses still unhooked, I used a garden hose to flush water through the entire system. Don't forget to open both heaters (main heater on the dash and the rear heater on the center console) in the vehicle when you flush or the old coolant will be trapped in the system and you won't have fully flushed everything.
It takes about 20 minutes give or take for the water that comes out to go from green to an almost clear fluid. I kept an eye on my temp gauge just to be sure, but it was fine and remained right in the middle the whole time. next I reconnected the hose, refilled the radiator and the reservoir container (pictured below) and allowed it to circulate. As I drove for the next few trips, I checked the coolant level and added as necessary.
Since I used water to flush my system and did not have any sort of equipment to clear all the water out, I used the Toyota pink 50/50 prediluted fluid rather than the red.
Here is the reservoir container
http://kidmoe.com/cooling2.jpg
The engine coolant level in the container should be between the LOW and FULL lines, when the engine is cold. If low, check for leaks and add more coolant up to the FULL line.
Step 2:
If you have Toyota coolant and sufficient coolant without a glaring leak, your next step should be to check the thermostat.
The FSM tells you pretty bluntly that the steps to removing the thermostat for testing are as follows:
1. DRAIN ENGINE COOLANT
2. DISCONNECT LOWER RADIATOR HOSE
3. REMOVE THERMOSTAT
(a) Remove the 3 nuts, wire clamp, water inlet and thermostat
with gasket from the water pump.
(b) Remove the gasket from the thermostat.
Testing....straight from the FSM:
http://kidmoe.com/cooling3.jpg
If the thermostat tests out fine, reinstall, check coolant levels.
Step 3:
The FAN CLUTCH is another culprit. The fan clutch itself can appear to be working properly.. spinning with the engine's rpm rate and, with the engine off, it may even appear to be tight and good. I replaced mine in a matter of minutes and determined it had most definitely been faulty as it was not howling quite the way it used to at start up and with my A/C running it barely ever turned on, which is not normal/proper function.
Here's the fan clutch:
http://kidmoe.com/cooling1.jpg
Removal is easy. No need to touch anything else, just loosen the 4 nuts being careful not to drop them (!) and carefully, without jamming the fan blades into the radiator, slide the entire assembly to the drivers side, up and out. Next undo the bolts holding the clutch to the fan, remove old clutch, place new clutch onto the guides, reinstall bolts, reinstall whole unit, and youre good to go.
Step 4: The radiator & radiator cap. WITH THE ENGINE COOL, remove the radiator cap. If the radiator cap has contaminations, always rinse it with water. The FSM tells the techs to use a tester to test the cap. Honestly, it is so cheap that you may as well replace it with a brand new Toyota one. Cheap insurance, easy install of course!
Inspect the radiator for leaks, see if any fins are damaged, etc. Replacing the radiator can be rather involved, I have done it twice and it is not fun or cheap. I went aftermarket and saved a LOT of money, but then again I had to do it twice since the first one was faulty. So pick your poison.
These are my experiences, hope it helps.
Step 1: Coolant
Are you using Toyota coolant? If not, flush your system and refill with genuine Toyota coolant. What I did for this was to unhook the upper and lower hoses on the radiator and drained the coolant into a bucket. Be sure to dispose of the coolant at an authorized local dump, do not dispose of it irresponsibly. Next, with the engine running and radiator hoses still unhooked, I used a garden hose to flush water through the entire system. Don't forget to open both heaters (main heater on the dash and the rear heater on the center console) in the vehicle when you flush or the old coolant will be trapped in the system and you won't have fully flushed everything.
It takes about 20 minutes give or take for the water that comes out to go from green to an almost clear fluid. I kept an eye on my temp gauge just to be sure, but it was fine and remained right in the middle the whole time. next I reconnected the hose, refilled the radiator and the reservoir container (pictured below) and allowed it to circulate. As I drove for the next few trips, I checked the coolant level and added as necessary.
Since I used water to flush my system and did not have any sort of equipment to clear all the water out, I used the Toyota pink 50/50 prediluted fluid rather than the red.
Here is the reservoir container
http://kidmoe.com/cooling2.jpg
The engine coolant level in the container should be between the LOW and FULL lines, when the engine is cold. If low, check for leaks and add more coolant up to the FULL line.
Step 2:
If you have Toyota coolant and sufficient coolant without a glaring leak, your next step should be to check the thermostat.
The FSM tells you pretty bluntly that the steps to removing the thermostat for testing are as follows:
1. DRAIN ENGINE COOLANT
2. DISCONNECT LOWER RADIATOR HOSE
3. REMOVE THERMOSTAT
(a) Remove the 3 nuts, wire clamp, water inlet and thermostat
with gasket from the water pump.
(b) Remove the gasket from the thermostat.
Testing....straight from the FSM:
http://kidmoe.com/cooling3.jpg
If the thermostat tests out fine, reinstall, check coolant levels.
Step 3:
The FAN CLUTCH is another culprit. The fan clutch itself can appear to be working properly.. spinning with the engine's rpm rate and, with the engine off, it may even appear to be tight and good. I replaced mine in a matter of minutes and determined it had most definitely been faulty as it was not howling quite the way it used to at start up and with my A/C running it barely ever turned on, which is not normal/proper function.
Here's the fan clutch:
http://kidmoe.com/cooling1.jpg
Removal is easy. No need to touch anything else, just loosen the 4 nuts being careful not to drop them (!) and carefully, without jamming the fan blades into the radiator, slide the entire assembly to the drivers side, up and out. Next undo the bolts holding the clutch to the fan, remove old clutch, place new clutch onto the guides, reinstall bolts, reinstall whole unit, and youre good to go.
Step 4: The radiator & radiator cap. WITH THE ENGINE COOL, remove the radiator cap. If the radiator cap has contaminations, always rinse it with water. The FSM tells the techs to use a tester to test the cap. Honestly, it is so cheap that you may as well replace it with a brand new Toyota one. Cheap insurance, easy install of course!
Inspect the radiator for leaks, see if any fins are damaged, etc. Replacing the radiator can be rather involved, I have done it twice and it is not fun or cheap. I went aftermarket and saved a LOT of money, but then again I had to do it twice since the first one was faulty. So pick your poison.
These are my experiences, hope it helps.