Radiator Fan not Cooling Engine Zetec

[NRW]

Here's an interesting problem. Noticed this a couple of times now on my 1800 Zetec. Car runs great temp guage goes up when pressing on then cools down as you would expect a normal cycle on the gauge. However when car stopped I let it idle and temp gauge slowly climbs then fan cuts in all normal but doesn't seem to bring temp down!! loads of hot air behind fan when running but no movement on gauge and it is still climbing. So switched off. I'm thinking air lock in cooling system maybe works ok when driving along but not enough air flow from fan when stationary?

[fatbaldbloke]

Hmm, first thing to check is that the location of the fan (in front or behind the rad), the rotational direction of the fan, and the design of the blades are all compatible.  If not the fan could vary from plain inefficient to actually sucking hot air off the engine and blowing it back through the rad.  When you're moving the fan will not usually be in use as the air flow through the rad from the velocity of the car is sufficient so it wouldn't matter if it was functioning wrongly.

[NRW]

The Fan is behind the rad and sucking air through it. It was a modular kit so all Westfield supplied parts. I did originally think perhaps I wired the fan backwards so as you say it was blowing hot engine air over radiator but thats not the case. When I finished the kit end of summer 06 this arrangement definately all worked just fine so I am at loss to see whats changed. I did have a major coolant leak (who hasn't!) sometime ago so I suppose an air lock is possible

[stu999]

If you keep 'pressing on', does the temp keep going up?

[carpetstu]

Just installed a 2l zetec and it runs a damn site hotter than my cvh ever did.

According to the temp gauge its at about 92 deg at normal uptp 100 deg when hammering it.

At first I was worried but the car seems happy enough at these temps.

[NRW]

I will have to try pressing on and see what happens!! but idling the temp goes to 100 on gauge then fan cuts in perhaps too late maybe?

[westy666]

It's fairly well documented that the mondeo's fan cuts in at 102 deg i think so the zetec is 'ok' with running hotter than some of its older counterparts.

Although, like you, I prefer to see the guage sitting on the friendly side of 100 myself.

I was running a 9inch blade fan originally and that held the temp static when it ran (ie didnt drop but didnt climb)  I recently went up to 11 inch and that reduces the temps as you'd hope.  

Obviously you'd like to think that you've been supplied an adequate fan if it was all part of the kit but its worth considering that maybe the fan just aint up to it.

Air locks usually expose themselves more when you give it some beans although there'd be no harm in having a quick bleeding session just incase.

Damian

[davew]

If you are looking for a new fan I would recommend one of these.

Car Builder Solutions

Moves lots of air and I have the 10" version on a 2l zetec.

[Man On The Clapham Omnibus]

My Pinto's gauge reads 100C when the fan starts. It does drop to sub-100 after a moment or two, though. An airlock might exacerbate things by reducing the flow at idle but not at running revs.

[NRW]

Thanks Westy666 re fan size I will look into getting a larger one fitted. It does thinking about it act as you say gets to 100C and then just sits there!! (when the car is stationary) Presumably there is a water thermostat and it's not getting a chance to work as designed under these conditions ie stuck in it's hysteresis loop!! as the fan can't quite cool the coolant temp enough.

Looking at the link for CBS I have a curved bladed fan but I don't know the diameter. Time to get out tape measure!!

[neilwillis]

My Zetec fan doesn't drop the temperature very quickly either.   As long as it holds the temperature, and doesn't let it run away beyond 102 degrees, it is doing it's job.   As soon as you start moving, the temperature drops.   Don't watch the gauges, just accept it is working, and worry only if the temperature soars.

It won't, your fan is working, and doing it's job.

[JohnCh]

Another thing to consider is the brand of the fan.  I used to have a 12” Perma Cool fan that was purchased because it was rated at a fairly stout 1650cfm.  It never cooled to my satisfaction when stopped at a light in the summer, so I replaced it with a 12” Spal rated at a similar 1630cfm.  I had heard that the Spal actually flowed more than advertised, and after looking at the specs of the motor, the Spal certainly seemed to have a lot more potential.   Before installing the fan in the car, I pulled the radiator nd performed a little experiment.  I took turns attaching the fans behind the radiator and hooking them directly to the battery.  I then used a Synchrometer in the front of the radiator to identify the highest air draw.  The Perma Cool topped out at 9 on the scale, whereas the Spal registered 12 at the same spot.

During the recent PNW2007 tour here in the States, I was stuck in a vile traffic jam in Canada for over 2 hours.  We only moved about ½  mile over the last hour and the temperature was 30C.  The fan never had a problem keeping the engine from breaking 100C.

-John

[chazpowerslide]

The Zetec is happy between 92 and 102 degrees, mine is rock steady at 92-93 degrees, the fan (Mk2 Fiesta) cuts in at 98 degrees (ECU controlled) and the temp drops down straight away.

With the Mk2 Fiesta header tank the system is self bleeding so if the system is plumbed in correctly your not looking at an airlock issue.

Do you have a thermometer that you can accruatly measure the temperature and how fast it drops?

My temp guage reads 80 degrees, the ECU sensor is reading 92, the ECU is accruate.

The ECU temp reading drops faster then the guage reading when the fan ficks in.

It also depends on where you are reading the temperature from (rad or stat housing)

You may not have a problem at all, it maybe the guage readings are not reflecting whats actually going on.

Chaz.

[neilwillis]

Like wot I said, you haven't got a problem, don't try to over analyse it.