Comptia

I recently bought a 97 ls400 and discovered it overheats when im not moving. Also the heater blows cold air when im not moving. I haven't checked to see if the radiator fan was turning on yet. Any ideas what the problem could be?

black_LS

Check the coolant level.

It sounds like there's air in the system, try bleeding it.

Comptia

Will try this. Thanks

LScowboyLS

check the fins of the condenser (the part you think of as the radiator, when viewed from the front) for bugs, dirt, plastic bags, or bent fins

when checking the coolant level, check not only the overflow (plastic) tank, but also check at the fill bolt, a large downward pointing bolt behind the thermostat housing - you will need a wrench or ratchet/socket to check this, and it should be full.

check that the electric fan is coming on, if the electric fan is not on during this overheating (and it should be on anytime the car is getting hot or the A/C is on), then a common culprit is the temperature sensor in the bottom corner of the radiator, down below the battery

also, the car can overheat for several other reasons, such as a worn fan clutch, clogged radiator, or even a worn out radiator cap

Comptia

The electric fan is not turning on when the car gets hot or ac is on. Should i replace the temperature sensor? Is it something i can do myself?

LScowboyLS

yes!

I don't know your level of mechanical competence, but you can always find a friend with good mechanics skills to help you, here is what I would do:

first, (optional) I would verify that the fan motor itself is good, using a heavy jumper with alligator clips, apply +12V power from battery to blue wire on connector at fan motor and connect black wire on connector to battery negative and verify that motor spins up

then check 30A RDI FAN fuse for continuity

finally, replace coolant temperature switch in bottom corner (driver's side) of radiator with a new one, aftermarket from auto parts store is OK on this part. The aftermarket part should be an exact replacement for Toyota part number 89428-33010 which Toyota calls "Temperature Detect Switch No. 2"

MattLS400

My 96 also has this temp detect switch....With reference to my half temp issue mother thread, do you think it wise for me to change this temp switch ?

Yamae

I often find guys who run without confirming what are ahead and behind of them.

LScowboyLS

only if the fan is failing to run when temp goes to half or A/C is on, it should be running in those two situations

Comptia

I bought the temp sensor from autozone, plan on putting in tomorrow. I might as well replace the other temp sensor while im at it, can i use the same one from autozone or should i get an OEM one?

LScowboyLS

the main one for the ECU is a green one with two wires that sits behind the coil and should be OEM, there is a guy on ebay selling them for $41 shipped, cheapest price I have seen for the real Toyota part

Attachment 498617

Comptia

Trying to remove the connector, do i just pull it straight out?http://imgur.com/G4yoZ5e
Edit:nvm i got it

MattLS400

Thats weird...Ive never noticed a one wire sensor for the gauge on my 96 :/

Comptia

Well i just took the old temperature sensor out (the one on the radiator) and the new one doesnt fit. Heres a pic
http://imgur.com/VpN05om
Im about to head to the store to see if they have the right one

LScowboyLS

this is why I gave you the original Toyota part number, so the idiots at the parts store might have some remote chance of giving you the correct one!