Cooling Fans coming on too early?

[Rodders]

Hello All,

New to this Forum, but have already had success from some of the posts!!....so thanks so far..

I have a question..

Four years ago our Radiator cooling fans....(1997 reg 406 1999cc Turbo Petrol Exec Estate)....failed and were replaced, since then I'd always thought theat the engine runs 'cold' never going above 70-80 on the guage. In fact even when stopped in traffic I cannot recall it ever going above 90 (half way).

Having just drained and flushed the radiator with all your helpful posts, I noticed that te fans actually come on before the guage reaches 70!!

Is that normal?
Can I re-calibrate / adjust them?...or should I?

Love to get advice on this, cheers.

[mjb]

That'll be your climate control running the aircon to maintain a comfortable humidity level. You've got 3 radiators at the front of the car - the main one, the intercooler and the aircon evaporator. The latter gets hot when in use so the fans are run to cool it down

Turn the AC to 'eco' and you'll see the fans stop.

If you're thinking your heating isn't as effective as it should be, check the coolant level and make sure it's bled properly - park the car with the drivers front wheel on a high kerb, brim the expansion tank, then bleed it using the bleed nipple on the passenger side where the pipe goes into the bulkhead

[Rodders]

Hi, thanks for the info'....it becomes a little clearer!

The full story started with poor / no heating, which given the cold spell was a problem. To be fair it has'nt been working well for a long time. So I got a local garage to take a look and they said that the matrix probably needed replacing.

I left it for a month or two...regeret that now!...and went to a different garage as the first one closed down. It was a local garage that did 'French' cars and had been recommended by a mate. I booked it in for a service / check for water leak / check the heater matrix / and a couple of other issues..

They called me and said that there was water in the oil, as the dipstick showed signs / and a leak in the radiator which also showed 'mayyonaise' at the point of leak. To be fair they said that it may need a new head gasket and did'nt want to change the matrix etc until I'd made a decision. Well they quoted approx £850 to do headgasket etc...
The cars not worth that much money really, so I said stop.

Instead I was going to 'patch' it and drive it until it completely died, I have 42 year old Karmann that needs work this year and I could use the 406 whilst it's off the road, if it lasted long enough!

They suggested proper Block Seal and recommended an engineering company which sold it, I got it and this is where I ended up this weekend....draining the system, looking at the fans etc....

So today I have drained / flushed / added Block Seal / driven and will drain / refill this evening.

Hopefully the headgasket may have been sorted ....there was no miss-firing etc before, so the guys at both garages said it stood a chance of working!
The three 'radiators' are all in one long unit?...there are two large fans in front of them, do they work independent of eachother and for different functions...Aircon / Engine / Intercooler?

[steve_earwig]

The fans run in series for low speed (so each fan gets 6 volts) and parallel for high. They should always run together and run on low speed when the air con's going from cold.

I did a "how to" for bleeding the cooling system here but you could do as mjb suggests and park it on a high curb/low wall/mountain.

[Rodders]

Thanks,

I am not sure whether the whole heating problem did'nt simply stem from losing water out of the radiator....airlock in the matrix somewhere whicjh i couold have easily bled!!

Anyway, when draining I used the quarter turn plug at the bottom right of the radiator, then found the two bleed caps, one on the output of the matrix and the other at the mater pump.

I managed to drop the Water Pump one, sod it!!! and could'nt find it again....so used a bycicle tyre valve cap, which does the job too!!

Whilst looking for the cap under the car, I noticed metal pipework running under the radiator almost like 'underfloor heating pipes'....are these a radiator too? they did'nt look like distribution pipes.

Also, raer passenger door has a 'hard spot and you need to force it over it to get the door to close, lubrication does'nt work..

And.....where can I get replacement keys?..both of ours are knackered and manually locking is not working well either!!!

[mjb]

Whilst looking for the cap under the car, I noticed metal pipework running under the radiator almost like 'underfloor heating pipes'....are these a radiator too? they did'nt look like distribution pipes.

And.....where can I get replacement keys?..both of ours are knackered and manually locking is not working well either!!!

Either get locks+keys+immobiliser+ecu from the same car in a breakers yard, or pay a dealer £100+ per key for new ones

They can be fixed though. Usually it's the outer casing and button which goes, you can just get another key off ebay and swap over the front plastic. If the PCB buttons are broken, someone handy with a soldering iron can replace them

[Rodders]

Hello,

Sorry for the late reply,,,,,,been away.

So can I buy a complete replacement key from Ebay and break open the existing one, take out the blade and transponder (?) then fit them to the new ket, throwing away the blank blade and transponder that comes with the new one?....is it easy to do?

Also, on the Head Gasket....it looks as though the Block-seal has done the trick. I followed the instructions to the letter and I am not loosing any water now, am yet to check if there is any oil on the dipstick. How long would it take to show?

Still need to replace the heater matrix though...suspect its clogged up as I'm getting hardly any warmth coming into the car, but have bled it etc...
Any ideas on how easy this is to do?

406 Exec / 2l Turbo / 1997 estate