: A Quick Question About My 94, Sup With The Dual Fans On??



DPGC23
12-24-06, 04:00 PM
Hello Folks
Quick Question,
It Has Happend Three Times In The Last Month,
But Basically, After Runing The Car For At Least 5 Mins Or So, The Service Engine Light Will Come On, And It Will Start Running Both Of The Fans Under The Hood.

I Noticed If I Stop, Turn Off Car, Wait 4 A Few Seconds, Turn It Back On, It Will Be "normal" Again.
Good Ol Wesso Who Used 2 Post Here Suggested It Might Be The Therm Sensor,
Although I Do Have Coolant, Every Now N Then The Light Will Turn On About "check Coolant" But Itll Come On For Like 4 Secs, Then Dissapear.

This Doesnt Happen Frequently, So I Dont Know What The Deal Is, I Figured I Would Ask The Professionals Though

Thanks

Dpgc23

carnut
12-24-06, 04:38 PM
You need to access any fault codes present. Whats probably happening is the ECU is commanding both fans on because either the engine is running too warm or the ECU thinks it is. A faulty coolant temp sensor could cause this, a weak radiator cap as well. Check the coolant in the radiator when engine is cold. It should virtually overflow from the radiator when you remove the cap. If its low find out why. The codes you get would narrow down what to investigate. Search this site to learn how to pull codes if not familiar.

N0DIH
12-25-06, 01:18 AM
carnut is correct, coolant temp sensor will trip both fans on as a safety measure.

You can put it in diagnostics and read the PCM temp, press OFF and WARMER together, using the fan buttons, go to pointer 24. Press OUTSIDE TEMP, this is coolant temp in degrees C.

Press AUTO to exit or shut off car.

This is reading the actual PCM coolant temp from the CTS. If ok, don't mess with it (it sucks to get to it!)

DPGC23
12-26-06, 10:58 PM
Car Nut,

The Radiator On The Caddy Doesnt Have A Radiator Cap, It Just Has The Container,

Let Me Try To Do What Nodih Suggestd,
Now Do I Have To Do This When The Service Engine Light Comes On? Or Can I Do This Anytime?

Thanks For The Help Folks

Dpgc23

BCs71
12-27-06, 12:49 PM
Even is the service light is not on, there will be a stored "history" code in the diagnostics prefaced by a "1".

But back to the problem at hand, when the fans both come on and you get a CEL (check engine light) you are in what is called "limp mode" or "limp home mode". Basically the car has a major sensor or device that failed or lost its signal (wire harness upligged or damaged) and is not reporting back to the PCM. So the car cannot adequately monitor data and determine how to provide air/fuel ratios in closed loop (when the car is warm).

So it basically sends the car back into open loop (cold engine, in your case the time before it turns on CEL) which is when the car does not read from all engine sensors. Instead it runs from a pre-determined set of air/fuel trims, usually over-rich (excess gas) in order to keep cylinders cool and keep engine from destroying itself. The downside is that gas economy and power goes down the toilet. Engine and other sensor life can be affected if problem left to linger.

So as the other stated, it is best to retrieve the code set in the diagnostics. The code will tell you where to begin your diagnosis.

The sensor in the front of the water pump WILL turn on both fans if it is unplugged or flat out fails. But there are other sensors which can cause this as well. So the code is the first place to look into, and then cheak all under hood wiring (especially to sensors).

Hope that helps

bigbluebrougham
12-27-06, 03:53 PM
Are 94's different from 95's? I can use pointer 8 and read degrees fahrenhiet. Maybe I am in the dark here...:confused:

DPGC23
12-27-06, 11:21 PM
Thanks Bcs 4 Explaining, That Helped Me Knowin What Could Be The Problem,
Nodhih,
Ihave Done What U Said,
It Came Up With A 66,
Now Usaid It Was Celsious,
So F Should B Above 100????
Dammm

That Doesn't Sound Rite At All

Thanks

Dpgc23

DPGC23
12-28-06, 09:02 PM
I Looked It Up Earlier, 66 Is About 150 F!!

As I Drove To Pepboys Today After Work, I Kept Monitoring It, It Reached 98 C Mannnnnnnn

Anyway, I Bought The Cts, 19 Dollars, Not Bad, So Im Going To Replace This Tomorrow After Work, Hopefully That Will Do It

Dpgc23

DPGC23
12-29-06, 08:06 PM
Ok, Not To Keep Beating A Dead Horse.
I Have Now Replaced The Coolant Temp Sensor, Which Was Fun Since It Wouldnt Budge,
And I Was Talking To My Boss, He Suggested I Do The Thermostat Also, Just For Kicks,
For 10 Dollars, Why Not

So I Have Now Replaced Sensor, Thermostat And All New Coolant,
So We Are Going To See What Happens.

Does 2 Gallons Of Coolant Soiund Right?

Thanks

Dpgc23

BCs71
01-01-07, 04:38 PM
So I Have Now Replaced Sensor, Thermostat And All New Coolant,
So We Are Going To See What Happens.

Does 2 Gallons Of Coolant Soiund Right?

Thanks

Dpgc23


Two entire gallons seems like a lot. Usually you want to aim for a 50/50 mix so approximately one gallon of water and one gallon of coolant might do the trick. Have the second gallon of coolant handy, however, to top it off.

If you drain the block by pulling the knock sensors then I would say that you need two gallons of coolant, then.

Any luck pulling the code from the HVAC panel yet which will tell you why the CEL lit up?

N0DIH
01-01-07, 08:48 PM
2 gallons is close to proper. We have a 14.8 quart (for V03 and V08 cooling) cooling system, so 2 gallons, 8 quarts, puts it just over 50%. Which is still fine. Honestly, less coolant % is better for cooling efficienency. I don't mind going a bit "rich" on coolant, as over time if I add any for anything, it will go to closer to 50/50.

DPGC23
01-02-07, 11:10 PM
Thanks For The Help All,
I Havent Had The Problem, And I Did This On Friday Last Week. I Have Since Driven It To A Destination Which Is About 14 Miles Or So 1 Way, Wit My Cruising Style, Thats About 15 Mins Or So Haha

Also, I Said 2 Gallons Because I Bought The Pre Mixed Coolant, My Boss Suggested I Go With That So I Wouldnt Use Tap Water,
But I Guess Ppl Will Argue Against That???

Thanks Everyone

Dpgc23

BCs71
01-03-07, 01:39 PM
Premixed if fine in my eyes, except that it usually costs a tad more considering it is 50% water (you are getting less coolant per volume per $$). But it's not that big of a hit to the wallet....

DPGC23
01-03-07, 11:46 PM
I Think I Saw The Regular Coolant At About 8 Dollars, Where As The Pre Mixed Was 10 Dollars

2 Dollars More, Plus I Dont Risk Putting In Urine From Someone1 Peeing In The Backyard, Im Down

Thanks

Dpgc23