Lhh305

Hi everyone,

I was at NTB to get my tires air check ( i drove for about 5 miles on a very hot day) suddenly the coolant just leaking out from the reservoir tank and it look like it is boiling. I shut the car off and let NTB take a look, they said I have to replace the radiator fan assembly for $600 because one of the fan on the passenger side is not turn on. And there could be more problems but they have to do a full diagnostic, and have to special order my radiator fan assembly, they told me to leave the car there for 3 days, so i left and went home to do some diagnostic with my friend.

- I checked the thermostat by boiling it and it open fine.
- The driver side fan come on when i turn on the AC and set it to 85, so i swap the 2 power connector and try again, only the driver side turn on, the passenger side still dead.
- I filled the radiator with distilled water and the prestone radiator flush solution and drove for about 20min without any problem, temperature gate is at haft way all the time, no leaking.
- I also swapped the 2 Relay (AC Comp) with (Fan No.3) problem still there.

So my question is what causing the boiling coolant, and why the passenger side fan is not working, I will flush the radiator and engine tomorrow, I can't find tutorial on where the 2 drain plug on the engine can someone help please.

I have a 2003 GS 430

Category5

well the coolant boiling over isnt due to one fan not turning on, have you replaced your radiator cap? I highly suggest you start simple, and cheap, cap, and I dont care if the therm. tested okay, they get stuck randomly when there bad s well..... any pressure loss will yield to boiling, even if the cap seems fine, its happened to me with every car... just try it, if nothing return it lol..... wrong size it didnt fit, but you changed your mind hahaha

NorthStyle

iTrader: (16)

Definitely agree with this. I should also ask, how many miles are on your engine and when (if at all) was the cooling system checked last?

Lhh305

I have 83000 mile, i'm the second owner and i think the cooling have never been flushed.

I changed the radiator cap, and the thermostat. it seem to work fine, But the passenger side fan still not come on. I think the passenger fan wire harness is bad, where can i find a replacement wire, autozone or ebay doesnt have it.

Mcon

iTrader: (1)

Do you saw the plugs on your fans to see if the passenger fan work? Maybe is your motor fan and nothing else. Or jump the driver wire to the passenger side fan if the plug is not the same and test the fan to see if working or not. Also, you said that you swap the relay but do you check your fuse? I just try to help because is something the I want to know what is the reason of this. Keep us with update please

"Lexappeal

Try replacing the radiator cap as the member above mentioned...that is usually the culprit when you have boiling coolant/water

Lhh305

Turn out that the radiator fan wire harness was bad, i had to cut out the bad part and reconnect it and cover it with electrical tape. Anyone know where i can order the radiator fan wire without purchase the whole radiator fan assembly?

Category5

Man hard to understand you, so hang on slow down here..... you said so replacing the radiator cap and therm. yielded you what results?

So what seems to work fine? Your old cap and thermostat? Did replacing those two NOW solve the overheating, or is it still overheating?

Do you have a multimeter? So long the male end plugs into the female end, and stays that way, well then theres got to be a cut somewhere in the line man. You can pull out the pins from the plugs, find the cut where ever it may be in your harness, which wont be difficult to find, solder on new wiring, slip on a new rubber plug, and crimp a new pin onto the wire, and replace it back into the plug.... You do not need to replace the entire harness which good luck finding but also wont be cheap....

Soo that said, where do we currently lie as far as your cars ability to run without overheating?

Lhh305

Replace the radiator cap and thermostat seem to fix the overheat problem, I put toyota red coolant. Both fan is working fine by rebuild & reconnect the wiring harness.Thanks everyone.

kit cat

iTrader: (6)

I also second checking the radiator cap as others suggested.

Also, not mentioned that comes to my mind... broken temp sensor (are the fans kicking in at 95 degrees celsius?) or maybe air in the system?

Lhh305

I got a check engine light on today with the code p0440 and p0446 turned out that the evap line with a green cap had come out, my check engine light is gone for the time being because I already erased the codes by disconnect the battery so hopefully it doesn't come back

tiger4life

iTrader: (16)

Don't know if you are still looking for the fan assembly but i had got a brand new one for under a $100 about a year ago (one of the motors started rattling on the original oem part). I think i got it off ebay, if not it was rockauto. No problems so far with the aftermarket replacement.