Overheating problem!

kurv · Nov 2, 2006

ok, so i'm kinda fed up. Ive been overheating for awhile now, and nothing seems to really fix the problem. I've so far replaced the waterpump, thermostat (new 180*), and the radiator, all the hoses are fine. I've been trying to burp the system for a couple of days now. I would say its sufficietly burped. My gauge will be fine for a few mintues, then creep up to the L or past. I turn the heater on full blast and the temp will drop to the O or the R. Im really tired of messing with this. Please Help!

The Green GT · Nov 2, 2006

Try changing your rariator cap. I changed mine and temperatures dropped a good bit. Get a LEV-R-VENT.

kurv · Nov 2, 2006

oh forgot to add, i also have a new radiator cap, with a pressure release lever.

The Green GT · Nov 2, 2006

Clogged radiator maybe?

Bosko5.0 · Nov 2, 2006

is your fan coming on?

kurv · Nov 2, 2006

im pretty sure the fan is comming on. It does for sure with the A/C. How do I test to see if it comes on without? Just wait till it heats up?

94Cobra69SS396 · Nov 2, 2006

I recently had this happen to me as well and it was caused by the ground wire in the connector loosing contact. I replaced the female connector in the harness and all is good with mine. The way I figured it our was I wiggled the harness with the air on and when I did the fan shut off. The I took a look at the harness and noticed the ground was loose.

1TallMF · Nov 2, 2006

I had a problem like this a few months ago, my car would overheat all the time in traffic unless I either had the A/C or heater on. But it would cool right back down once I got moving fast enough. Set your a/c to "off" and just let it idle in the driveway and look at the fan to see if it turns on when the temps reach close to halfway on the gauge. Mine never did turn on, and I traced it back to the temp sensor, it had an open circuit (no resistance at all). Got a new sensor for $25 and now the fan works fine, no overheating.
Good luck.

kurv · Nov 2, 2006

awsome thanks for all the replies, I think i've located the problem. I let it idle for a bit and as the temp climbed the fan never came on. Until I hit the A/C. So I suppose i need a new sensor.. Where is it located? Also, what would be the downside to installing a manual fan switch and just having the fan constantly running?

The Green GT · Nov 2, 2006

kurv said:
Where is it located? Also, what would be the downside to installing a manual fan switch and just having the fan constantly running?

I think you just change the harness, or you might need to change the CCRM. There is a relay in there for it, but I think that kight just be for the high speed fan. Im sure someone will correct me if Im wrong. I have a buddy checking my old one and I can hook you up if there is nothing wrong with it.

And using a manual switch would just make it take longer to reach nor,al operating temperatures. Unless you left it off till about 150*

HISSIN50 · Nov 2, 2006

The t-stat is what regulates engine temps. You can have a fan run constantly (as with mechanical fans) and the engine still heats up just as it normally would (t-stat is closed, so coolant being cooled in the coil is not flowing in the engine).

The downside of running the fan constantly is the fan wear and load on the E-system.

Low speed should come on at ~208*F and high at about 228*F. Manual switches work fine if you dont mind toggling them (I got tired of it). Or go with a stand-alone fan controller.

Good luck.

ProKiller · Nov 3, 2006

you replaced the radiator with a stock one or an aluminum one? that would have went a long way in keepign it cooler. a manual fan switch is a good idea to have.

1TallMF · Nov 3, 2006

The sensor takes 2 minutes to swap, its right in behind the thermostat housing on the lower intake, coming off that black metal heater tube. Just unplug it, unscrew it, and put the new one in (with teflon tape on the threads). Before you do it, make sure you relieve the pressure in the system by opening rad. cap, to avoid a mess. I learned that the hard way
Your CCRM is working fine, since the fan comes on with the A/C or heater. It uses the same relays. Its just that the signal is not getting to the computer to tell it to send power to the relay once it reaches those temps.

Hooking up a manual switch is always another good idea. There are plenty of good write-ups, as mentioned. I'm far to lazy at this point to do it though..

kurv · Nov 3, 2006

thanks for all the replies. I changed the sensor, and also learned the hardway. However, the fan is still not comming on when hot. Maybe a bad ground? Or a freyed wire? Possible fuse? Any other ideas?

HISSIN50 · Nov 3, 2006

Are you using a real gauge to determine temps? Otherwise that tosses another variable into the diagnostics.

You know high speed works, but you need to let the car idle forever to reach the high-speed temp threshold.

When the car is at 208*F+, look at pin 14 of the CCRM for having 12 volts. It should (to energize the low speed CCRM fan relay).

There are several ways the diagnostics can go depending upon what you find. There can also be an issue with the PCM's signal for the low-speed fan, with the EDF relay control brain, and so on.

Good luck.

kurv · Nov 4, 2006

So after checking fuses, and grounds, and all possible electrical connections. Still have no clue as to why the low speed fan is not comming on. If I unplug the electrical connector to the temp sensor, the fan comes on. So does the check engine light... I really don't want to have to take it back to the shop

HISSIN50 · Nov 4, 2006

kurv said:
If I unplug the electrical connector to the temp sensor, the fan comes on. So does the check engine light... I really don't want to have to take it back to the shop

That's normal. When the ECT circuit is open, low speed should come on as part of the system safeguard.

Now you know that low speed works (it should be low speed that comes on with the ECT unplugged). You can check your ECT for calibration at 210*F coolant temps.

Another way to see if the low speed fan comes on (to be sure) is to do self tests. Both fan speeds should cycle at the beginning of the code retrieval.

When the car is nice and hot (over 210* F), if you can tell us if you have 12 volts at Pin 14 on the CCRM, that will help. It sounds like you will not have this input signal.

Good luck.

kurv · Nov 4, 2006

So I don't have a voltmeter, suppose I could pick one up though. However, I just pulled codes, and this is what I picked up

KOEO
564 - Electro-Drive Fan circuit failure

So I guess the circuit has failed, I checked all the fuses and all of those where good. Ideas?

HISSIN50 · Nov 4, 2006

kurv said:
So I don't have a voltmeter, suppose I could pick one up though. However, I just pulled codes, and this is what I picked up

KOEO
564 - Electro-Drive Fan circuit failure

So I guess the circuit has failed, I checked all the fuses and all of those where good. Ideas?

Did you pull codes after you had disconnect the ECT (and the fan come on)?

If so, it's possible that your having done this is what triggered that code. It's for the EDF control that I mentioned earlier. However, since the fan come on when you opened the ECT circuit, the EDF control (in that one instance at least) worked like it should.

I'd clear the codes and pull them again after you warm the car up fully (to where low speed should have come on). This will provide a fresh palatte for codes to be restored.

Good luck.

kurv · Nov 4, 2006

I had the ECT connected as it should. As I pulled the codes, The low speed fan came on first, then high speed. I've since upluged the battery, to clear the system. Pulled codes again, with the same results.

Overheating problem!

kurv

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