cooling fans

[mikexgough]

If the ac is switched on, the rad fan/s will come on when necessary (not sure if they still do when the vehicle is in motion & the forward motion takes care of the cooling, if this is so, then how?), thus as soon as the stat opens & allows any coolant through the rad, the fans will always be spinning & at low speeds/stationary will help to keep the temp down without the system having to get up to fan switch temp. You are right in that the compressor/fans will effectively be putting more load on the engine, but as the fans will be cooling the rad it won't show as elevated running tempsat low speeds/stationary.

Just done some crawl low speed town running @ 30C outside .....Aircon on from start...... never got to 12:00 or 50% on the Temp gauge.... usually I run at 50-55% (12 to 12:30)on the gauge......normal running with aircon off

I know the Citroen C3 of Hazel's runs 3 lights (it has 6) normally and goes to 2 in the winter on cold days......runs 2 lights with Aircon running.....

[g8dhe]

Yup I was missing that - the fans are forced on when A/C is selected so yes, if the Stat is open there will be more cooling going on in total.

[missfixit70]

It's good that the questions are being asked as it means people are checking everything & testing & thinking about everything. It's all very well having the theories of what should happen, but it's putting it into practise & seeing what actually happens that matters most & finding out why things are happening if we don't think they should be. Accept nothing & question everything

[steady1946]

Hi All
I had a word with my mechanic today and he said he has tested the sensors to see if they work,by putting them in a saucepan of boiling water and then applying more heat until the fans start working. This did happen,so there is no fault electrical.He is almost sure that the fault is a flow problem,either the stat or the rad.So tomorrow he is going to test the stat. The sensors and stat he got from Bongo Bits.I hope it is only the stat at fault and not the rad .
Will let you know the outcome.

Ed

[missfixit70]

So has he measured the temperature at the top hose as the system heats up? There may not be a problem at all? Testing the switch in a pan of boiling water (boiling water & then add more heat? how?) is a very crude test unless he measured the temp at which it switched? Did you give him the resistance values at 20 & 60 degrees so he could check it accurately?

[steady1946]

Hi Missfixit
I did give him your readings and he said he would use them to check the sensors.
Ed

[jaylee]

We have just returned from a holiday in the Peak District.
While there we got stuck in traffic on the A57 near Stockport/Manchester.The Bongo engine was getting quite warm and got up to 3 quarters when my Mason alarm started chirping,The cooling fans did not cut in at all.When I returned to the campsite I called out the breakdown people.He tested all the plugs to the fans and the fuses and could niot find anything wrong with them.He suggested when it came to going home I should have my air-con on which would operate the fans.
When I got home I took Bongo to my local Bongo garage(fury approved).He said it was probably the 2 sensors on the engine.I left the Bongo with him to repair.He phoned me to say that he had changed the sensor ,but the fans would not cut in at the right temperature.He phoned round a few other Bongo garages and they said it maybe the Mason alarm causing the trouble.
Could this be right?

Ed

This isn't the first time i heard an accomplished Bongo mechanic mention the mighty Mason can cause trouble... I heard also it messes with the ECU... & I had to strongly disagree for virtually the same reasons.. An unmodified temp gauge does nothing till its way too late.!

It's just there to un-damp the gauge & sound at a set temp slightly above normal...
I don't think it's a temp sensor... Just an alarm!
Had to reset mine a little lower after a service...

[missfixit70]

It's a shame when they don't take the time to understand what's what, it's that old school mechanic "I know better than you" thing - epsecially when dealing with women

[jaylee]

It's a shame when they don't take the time to understand what's what, it's that old school mechanic "I know better than you" thing - epsecially when dealing with women

A mechanic should never underestimate who they do the job for... If i get a guy in to trim my hedge, don't mean i know nothing about gardens.. Just means i can't be arsed!!

[missfixit70]

I trim my own...... naah too easy & obvious

[jaylee]

I trim my own...... naah too easy & obvious

From time to time i let my rock & roll extravagance get the better of me!

[mikeonb4c]

It's a shame when they don't take the time to understand what's what, it's that old school mechanic "I know better than you" thing - epsecially when dealing with women

You're 100% right about that Kirsty. We hod one like that - Mr Chuck Norris tasty Geezer. Had my wife conviced I was a nutter to want a thermostat changed even though it showed all the classic signs. Finally I got another garage to do it. Normal service resumed.

[mikexgough]

My Pal is an old school mechanic.......he likes to make sure he has the real info.....he never assumes that he knows a vehicle......

[steady1946]

Hi All
Finally got my Bongo sorted out. The mechanic was going to check the thermostat to find that there wasn't even one there. He also had the rad checked for any flow problems and found that it was only working at 70%. He thinks that the rad was probably faulty and that is why the stat was taken out to cover up the fault. I have had a new rad fitted and a stat and 2 sensors. He tested to see if the fans came on (with the Mason fitted),they did not come on until it got to near the 'H'. So he had a word with a Bongo garage in Bristol who said that the Mason can cause the temp to go up too much. The Bristol garage said the only thing they put on a Bongo is the Haydn Low Coolant alarm.So I said to remove the Mason,and the fans now come on at about 1'oclock. She also runs a lot better.


Ed

[Rhinoman]

I agree, with the ECU parameters set at a fixed (IMHO a too high) temperature the Fans will kick in at the late stage.

At what temperatures should the fans cut in? I think I have located the code in the ECU but I need to calculate what temperatures equate to the stored values.