ej888

Hi guys I was hoping you guys can help me as I have changed the radiator, radiator cap, and thermostat. My car is overheating when in stop and go traffic or when idling for around 2 minutes when the engine has warmed up. It takes around 10-15 minutes to overheat on a cold start just idling. Before changing the thermostat my fan would not kick in when overheating. After I changed the thermostat, the radiator fan would kick in when it suppose to and no more overheating for two weeks.. until now. Really weird as I don't know what to do now. I know the fan works as sometimes it still kicks in, but sometimes it doesn't and the engine overheats. Do you guys think it's the coolant temperature sensor? Also I don't know if this would relate to the overheating but when I turn on my A/C the fan for the A/C turns on but radiator fan doesn't. Is this normal?

Armychris89

i have a 93 ex and had the same problem with my d15b8, i'm sure yours has stock z6. Anyways changed the radiator, thermostat was new when i bought the car. The fan wouldn't come on and checked every ground, fuse, relay and sensors no problems. I would start to overheat every 15 miles or so and half the coolant would be gone. As i was changing front end parts on my drivers side i noticed coolant on the firewall side from the lower timing cover to oil pan. It was the water pump that was bad and cools super well now. I had to hardwire the cooling fan to a switch in the car but other than that its fine now. So, in conclusion, you might want to change your waterpump out. It's a pain to do it but its better than having a blown engine. Take the wheel off, crank pulley, power steering, alternator, upper and lower timing cover, timing belt and the five or six bolts holding the pump on. if the old pump moves inward and outward then the bearing for it was bad. Good Luck.

Jockone

It could be coolant temp sensor but it could also be water pump,do you know when t.belt and pump were done last?if not it might be worth doing them.

Group Tenacity

sounds like the water pump to me. had this happen years ago.

95EG2

yea CTS or water pump... stop driving while overheating or u will have a blown head gasket

ej888

Thanks for the replies guys. The water pump along with the timing was changed at 90k miles and I currently have 120k on the clock. I'm wondering if I only over heat when its in stop and go traffic (less than 5-10mph) or idle for about a minute or two, might that still be a water pump issue? Right now I'm leaning towards replacing the CTS. Thanks in advance.

dpetro1

no offense to anyone above but none of those suggestions sound correct. if i read correctly, you said the car only overheats when the fans fail to come on. so you need to troubleshoot your fan problem. originally your bad thermostat was causing the fan not to come on. now if the fan is coming on only sometimes i would first look to air in the system. was the radiator bled properly after the thermostat change? also you can jump the fan switch to make sure the fan motor turns on. then check the relay and fan switch at the thermostat housing.

Armychris89

I think this user could could be right by jumping the fan motor, attach a 12v to the black wire and a ground to the blk/red wire. If the fan turns over runs continuosly then the fan is fine. Next check for ground to the fuse block and then test the relay and fuse.

ej888

I just jumped the fan and it works. I don't know if this is correct but I bled the system like this. Max the heater, start the engine with radiator cap open, let the bubbles come up, then top off the radiator. Is this the right way to do it? How would I check the relay and fan switch? Thanks for the replies guys.

SHotime2511

Why anyone would say this issue sounds like a failing water pump I don't know.
Sounds like the fan isnt working like it should,this could be because of several reasons.
Fan relay
fan motor
wires to the fan
coolant temp sensor (this one should throw a MIL)

dpetro1

this sounds right. you should let it bleed with the cap off until the fan cycles on. if you can jump the connector and it turns on then you need to look to the fan switch or relay. the fan itself is obviously good.


coolant temp sensor would throw code 6 if bad but it does not control the fan. its a 2-pin sensor under the dizzy that gives temp readings to the ECU for fuel/timing adjustments. the fan switch is on the thermostat housing and would not throw a CEL if bad.

ej888

Oh man! I just found out I have been mixing up the coolant temperature sensor with the engine coolant temperature switch. Like you guys said the sensor doesn't control the fan but the switch does. Learn something new everyday haha. Before I buy the coolant temp switch, how would I test the fan relay to see if it's working properly?

dpetro1

i think jumping the connector proves the relay works. you hear the relay CLICK and the fan comes on. maybe replace the fan switch, re-bleed the system and go from there

sloassSi

Fan might still be ok... What kind of thermostat did you get? AutoZone thermostats can fail any time even if they are only 2 weeks old... I would recommend getting a OEM thermostat from the dealer before doing anything else... If that is what you have, then troubleshoot your fan...

ej888

I went to a local auto store that sold me a thermostat from Stant. Are they any good? When I was comparing and compressing the thermostat spring from the old thermostat to the new one, the old one was super stiff compared to the new one which compressed with very little effort.

ej888

Well today I replaced the coolant temp fan switch and everything runs fine now. Fan kicks in when stat opens and no more overheating. Thanks for all your guys help.

teggyluva90

wow i may do that to my 98 ej8 because it overheats right away in 3 minutes but i just changed the headgasket, my fan doesn't turn on and i didn't know you had to bleed the cooling system. 1st let me buy a new CTS also buy a thermostat who knows if the lady even changed it that i bought my coupe from haha!.

Diregraf_Capt

I too have a problem with overhearing in my 1998 Honda Civic Ex. I changed the radiator, and .thermostat. I also changed the fuses. it'll start and run for about 10 minutes before it gets into the red. The previous owner changed the water pump before me so I know its not that. I think it is the ECT but I'm not one hundred percent sure. I'm open to ideas

RichCMemphis

First off you may want to start a new thread of your own seeing as how this one is over 2 years old.

Secondly, are you getting pressure built back up into your radiator? Is the oil milky? Do you drive it while it's hot?

Tec_Keenen

It could be the cooling temp switch, a good way to test this is taking the connector from the switch and use a paper clip to complete the circuit. If the radiator fan comes on then most likely the a/c fan is bad.
I'm currently dealing with the fan thing myself, but I'm not authorized to handle refrigerant and it looks like you have no choice but to remove the a/c in the way of the fan coming out.

Lastly, I made a tester for the fan itself and went to the junkyard pulled 3, and tested it off their batteries. However, I put just the blade sense the blade is removable.
I hope this works. Good luck!