[Kevin1990]

Gentlemen,

i found a few theories about the strange cooling fan activation arround 60 °C before thermostat opening....


Does anybody have a solution for this problem? Or is it "normal"?

My Saratoga has it, my Voyager has it .....

A/C is dead on both, maybe that´s a fact....


I tried to change the thermostat, measured the housing temperature (infrared), changed the temp. switch ....


Thanks
Kevin

 

[Doug D]

60 C = 140 F if I converted correctly. Sounds like the CTS may be faulty?

Back when I was having issues with one of my old Acclaims (since long gone), using a regular thermometer in the radiator (cap off), the radiator fan wasn't activating until the coolant temperature was about 210 F. If I remember correctly it would shut off when the temp dropped to about 180-185 F.

 

[ntrodda]

I have a dealer service report for a 2.2L that says normal operation is for the fan to come on at 212 degrees F and to go off at 100 degrees F. That is normal operation, regardless of whether the thermostat is open or not. So the thermostat should open before the fan comes on (160 to 190 degrees F).

The coolant temp sensor is what tells the computer to turn on the fan, isn't it? Maybe that is bad?

 

[Bob Lincoln]

I have a dealer service report for a 2.2L that says normal operation is for the fan to come on at 212 degrees F and to go off at 100 degrees F.

Not true. The coolant will never get down to 100F with the engine running. It comes on around 220-230F and turns off somewhere down around 190F or so, roughly. But certainly it will never run the temperature anywhere near down to 100F.

If he has changed the CTS already, and the fan comes on before the engine is warm, it's likely that he has a trapped air bubble. When the bubble reaches the CTS, it exposes the sensor to hot air, the sensor thinks the engine is too hot, and turns the fan on. The solution is to bleed the air out of the system, which you can do by parking uphill, removing the radiator cap when cold, and idling the engine with the heater on full, until the air bubbles burp out the radiator. Then top it off and install the cap.

 

[Kevin1990]

Not true. The coolant will never get down to 100F with the engine running. It comes on around 220-230F and turns off somewhere down around 190F or so, roughly. But certainly it will never run the temperature anywhere near down to 100F.

If he has changed the CTS already, and the fan comes on before the engine is warm, it's likely that he has a trapped air bubble. When the bubble reaches the CTS, it exposes the sensor to hot air, the sensor thinks the engine is too hot, and turns the fan on. The solution is to bleed the air out of the system, which you can do by parking uphill, removing the radiator cap when cold, and idling the engine with the heater on full, until the air bubbles burp out the radiator. Then top it off and install the cap.

You´re a genius!

THATS´S why i hear some air bubbling when driving away in cold condition!

I tried to bleed it on a level surface, but still some bbbling, also on my Voyager.
I´ll try it right now, i was not thinking about the surface, damn...

 

[Bob Lincoln]

Park high enough to get the radiator cap above the level of the thermostat housing. That should dislodge a bubble when running.

Every time you open up the cooling system to service something, or change/refill the coolant significantly, you must bleed the air off.

 

[B10alia]

The Stant Superstat has a jiggle valve that will prevent this when first installed.
Why are you getting air in the system, though? If you've had the condition for a while, the air should have worked its way out by now. You could be looking at a cracked cooling system component or a bad head gasket.

 

[Kevin1990]

I just found a (maybe serious) problem yesterday.

A bit of coolant was leaking down the lower radiator hose, but not much, just a few drops. But the coolant reservoir was almost empty.

I flushed the system last year, but never had to add a bit of coolant. Oil is clean, just like the water itself. BUT you still hear some bubbling when driving away in cold condition.

I tried to bleed it, no bubbles appeared.

And NOW it comes......the fan only activates before thermostat opening, when i come to a complete stop. if i roll in 2nd or so, the fan wouldn´t come on. Only after a downshit to 1st. or a complete stop....

 

[ImperialCrown]

Some vehicles had PCM software to turn on the radiator fan during warm up in order to prevent the radiator steaming the condensation off in cool weather. This was a huge customer concern back in the 1980's when people were just getting used to electric radiator fans instead of the mechanical water pump-mounted fans that ran all the time and kept the steam from billowing out of the grille. It was disturbing when people thought that their new car was overheating or leaking when the temperatures were ~40-50 deg F.
The minivans had the condenser next to the radiator and both had independent electric fans to run when needed. The A/C condenser fan can run whenever the A/C or defrost mode is selected. If you hear a fan come on, it may be important to make sure which one is coming on. The cars had a common fan to cool both the radiator and condenser.
A 'hot' bubble from a combustion chamber head gasket leak passing by the CTS can turn the radiator fan on for an otherwise cool engine as well.

 

[Kevin1990]

Interesting to read!

I know, the minivans used seperate fans for A/C and radiator.
But it´s also the radiator cooling fan that comes on at the first stop after 5 - 6 minutes of driving, no defrost or A/C on (both A/C´s are dead).

 

[valiant67]

Yep, the fan should come on at a stop (regardless of engine temp) as Imperial Crown stated.
It's easy to loose coolant from a minor leak like your lower hose. A radiator pressure tester sure can come in handy in the tool box.

 

[Kevin1990]

OK thanks a lot!

Yeah i checked it yesterday, the radiator is gone, it´s leaking a bit arround the hose outlet, a new one should fix it this.

 

[B10alia]

Figures, the radiator on my Spirit had a huge hole in it, the rotted area was about the size of a softball. They certainly don't last forever. You may be able to get a fair amount of money for it at a metal recycler; a lot of times, they're made out of a copper alloy. As long as the bad radiator didn't cause overheating, you should be good to go. I would recommend a coolant change though, just to get any junk from the radiator out of the system.

 

[Kevin1990]

Mine is just a bit wet arround the hose, not even stains on the ground.

I flushed it a year ago with a special liquid from "Liqui Moly"; awesome stuff!
I also change the coolant every 20 000 KM on each of my vehicles.

 

[Bob Lincoln]

That's way too often, generates a LOT of unnecessary toxic waste. Coolant these days is good for a minimum of 5 years or 50,000 miles (80,000 km), some even longer.

 

[Kevin1990]

That's way too often, generates a LOT of unnecessary toxic waste. Coolant these days is good for a minimum of 5 years or 50,000 miles (80,000 km), some even longer.

You´re right on this one, i just recognized some left over dirt in my Saratoga´s cooling system and just drained the radiator itself and refilled it.
My Voyager got almost every component of the cooling system new, including the water pipe on the 3.0, every hose, every sensor.....a hell of a rust mess.....