406oc.co.uk

Hi,

Ive searched throught the forum and found that there are 2 bleed screws on my 406 1.9TD as shown below:



1 - coolant bypass pipe
2 - heater matrix

Can someone tell me if their is another one on the thermostat housing (which i assume is 3)? Is is a allen key type or a dust cap type (ie same as the other two)?

Thanks for you help guys!

John

I don't know diesels at all, but 3 really doesn't look like a thermostat housing - the hose coming off it is too small and looks to be going to a charge pipe

The thermostat housing is more likely to be somewhere near the fuel filter, probably where the blue and brown connectors plug into

hmmm... thats my problem you see, Ive read theres a bleed screw on the thermostat in some models but i dont know where the thermostat is

Number 3 is connected with the injection pump.

On my 406 HDi the bleed screw is exactly where mjb says, it's on the plastic housing below the two connectors, below the fuel filter (to the right of the dipstick).

Mine is slightly different however, my fuel filter is somewhere else.

If you are having serious trouble bleeding the system, one trick I use is to remove one of those sensors and fill the system with the sensor removed, air usually comes out easily from that point, especially if you point the car uphill.

jasper5 wrote:On my 406 HDi the bleed screw is exactly where mjb says, it's on the plastic housing below the two connectors

*STRUTS*

The two connectors are quite recognisable as the plugs to the coolant temperature sensors - one for the dashboard and the other for the ECU, and are usually located on the thermostat housing...

If you are having serious trouble bleeding the system, one trick I use is to remove one of those sensors and fill the system with the sensor removed, air usually comes out easily from that point, especially if you point the car uphill.

The problem is that there are parts of the system which are higher than the reservoir filler, so you can't get all the air out on the flat without making up an extended header tank out of a butchered pop bottle or similar. My technique which has never failed me yet is to park with the drivers side in the air - a heavily cambered road or just putting the offside up a kerb does the trick.

cheers for all the info lads!

yeah i know all about making the expansion bottle. Its just the location of the bleed screw on the thermostat housing that im trying to find.

After a bit more reasearch im wondering if this is it - number 18 circled:





So i took a photo of it on my car:





Is this a bleed point? Has anyone opened it? Do i need to?

That isn't intended to be used as a bleed screw, I would imagine it would be very difficult to get an allen key on it.

You aren't saying why you need to bleed the system, will it not bleed from the other two bleed valves?

Have you got a cooling system problem?

Changing my radiator tonight. Just want to make sure i bleed it properly thats all.

Cheers anyway

Ah right, good luck with that.

You should follow what I wrote earlier, have the car facing uphill before you fill it with coolant, or jack it up at the front, then undo the bleed screws that you can see, take out the coolant sensor as I said before, then fill the system, wait until coolant floods out of where the sensor fits, put sensor back in and let coolant bubble out of bleed screws, then start it and run it. When water flows out of the bleed screws, tighten them up and run it until warm, check heater is working and radiator fan works.

Don't burn your fingers

Well, changed the radiator last night. What an absolute c**t it turned out to be!!

Had all the coolant drained and pipes removed in about 10mins. Well all the pipes except for that fcuker on the lower drivers side The bloody thing had corroded to the rad. Took me 2 hours to get it off! I had the radiator angled out of the car trying to pull it free - i tried prising the pipe off with a screwdriver/chisel - eventually i took to it with an air hacksaw and cut through the lower corner of the radiator to get it off. And yes i had removed the metal clip

Then i spent another hour putting that pipe back onto the new radiator. Ended up knocking it on with a prybar and hammer lol.

So much for a half our job lol. Eveyting was simple except for that. Least its fixed now!

Well done

I didn't want to put you off doing the job, but that's normal for those radiators, done a few now.

I did wish you luck

jasper5 wrote:You should follow what I wrote earlier, have the car facing uphill before you fill it with coolant, or jack it up at the front, then undo the bleed screws that you can see, take out the coolant sensor as I said before, then fill the system, wait until coolant floods out of where the sensor fits, put sensor back in and let coolant bubble out of bleed screws, then start it and run it. When water flows out of the bleed screws, tighten them up and run it until warm, check heater is working and radiator fan works.

You forgot the "run it with the header tank cap off until the thermostat opens and the tank suddenly empties, then refill and once it cools down re-bleed"

So now you know I'm not perfect

must say tho, noticed that the temp gauge doesnt ever seem to go above 75-80 degrees. Is this normal? Also their is hardly any heat coming from the vent below the windscreen but there is some heat coming from the vents on the dash. Car always was like this since i bought it (1 month ago) so this wasnt caused by me changing the radiator.

Any ideas?

It could well be the thermostat is stuck open. Usually the thermostat is closed until 80-90 degrees C so coolant only circulates between the engine and heater matrix. When it opens at 80-90C it lets the coolant get into the radiator to stop the engine from overheating. If it's stuck open, the engine will never get up to temperature so you remain cold inside...