- This topic has 37 replies, 11 voices, and was last updated 12 years, 1 month ago by
.
-
Topic
-
I Am in a automotive class and we have been working on this 2001 Toyota Camary with an Over heating problem. we have found records on what has been replaced in the past and they were Water pump, all 3 temp sensors, cooling fan sensors, and thermostat. the temp gage on the dash has been showing at 3/4 instead of 1/2 (Normal) so we have tryed a NEW radiator thinking the system had a restriction in it but with a new radiator it still overheats. we have GOOD Flow of coolent. when we turn on the heater in the car the temp gage goes down (Cooling the coolent off) the cooling fans come on at the correct temp. we also did an OHMS check on All the sensors and they are Within spct. SO the instructors and us are completly stumped could anyone give us any ideas to try?
-
Replies
-
I believe that car calls for a 180F thermostat.
the temps are high. check to see if its the right
thermostat and temp range.Did you say that the scan tool is showing a normal (188 deg F) temp, but your gauge is saying the temp is too high? Reading your post, although the gauge is up that seems to be the only sign of overheating, ie no boiling over or other problems aside from the gauge showing a high number. I believe you when you insist you burped the system correctly.
If the above is all true, then I would wonder if the gauge is out of calibration. You wouldn’t necessarily detect that by simply checking wiring or resistance of the gauge. I would inspect the gauge on the instrument cluster to see if it is seated correctly. If it is, I would swap that gauge out and see if a new gauge shows the same numbers.
When the gauge is showing 3/4 what is the actual temp of the coolant in the engine? Maybe the gauge in the dash is just bad. I would go to a parts store and buy one of those aftermarket temp gauges for like $8, plug it into the block and see what it says. If it doesn’t go over 210 at any time it’s good in my opinion.
All of the sensors have been changed out and replaced with new one the prevous group of students kinda just “Threw Parts” at it not really Diagnosing whats causing this to happen. I asked my instructor about putting in an after market sensor to make sure the gage on the dash is correct. he has told me that he hooked up a scanner to the car to see what the temp is actually at when BOTH Cooling fans turn on. he told me 187-188.
Its reading 3/4 up the gage this type of gage only has “C” And “H” the normal Operating Temp Is right in the middle of “C” and “H” (1/2)
NEW INFO! we took the thermostat out of the car and put coolent back in it. we ran the car and the temp STILL Climbs WITHOUT the thermostat in it. the cooling fans have 2 speeds Low and High. ONLY the high is working. we turn the heat on in the car and it keeps the gage at normal. but it isnt the thermostat since it still gets hot without it. Any suggestions?
Compression and leak down test the engine. You said there is no air in the system. The radiator is new. The thermostat is new and working. Both the CTS and thermistor were replaced though I doubt the thermistor was. You are left with head gasket. Just check already. They blow between the 2 and 3 cylinders.
We thought there was a blockage in the old radiator so we swapped it out put in a new radiator it did the same thing so we put the old radiator back in and took the new one back.
We just took the thermostat out today because the upper radiator hose had pressure and was pretty warm so i felt the lower hose and it was still sone cold. then i got thinking that if there was no thermostat in it that the car shouldnt get hot or as hot so we took the thermostat out and closed the cooling system back up added coolent. air bubbles were comming out and i know we got all the air out of the system so all the coolent is doing is circulating through the whole system with NO thermostat. the gage on the dash still climbs high. we turn on the heat in the car and the temp gage goes down to about normal. we have no idea what is going on. it shoundnt get hot with no thermostat but it is.I need to make a video on this topic because I keep going back to this. The upper radiator hose is SUPPOSE to be hot and the bottom one cold, this is the radiator doing it’s job, it does cool the coolant after all.
Yes the Radiator is doing its job. we ordered a new thermostat and i checked the temp rating on it they both say 86C is when they open up. when we felt the hoses the top one was warm but the bottom one was cold and the gage on the dash was past normal operating temp.
Given that the fans are coming on and it doesn’t seem to be overheating it may be a problem with the gauge circuit. I suppose the only way to know is to check the readings on that circuit to see if it’s working properly, perhaps the gauge is reading wrong.
Yeah, arrows are again pointing to the gauge. The one other thing that came to mind when you said that the lower hose is ‘stone cold’ is poor flow (either obstruction or pump failure), but you said above in the thread that flow was fine. And, I would have expected to see very high temps with your scan tool. The fact the scan tool said temp was fine really should be your best diagnostic clue.
- You must be logged in to reply to this topic.