406oc.co.uk

Hello..... Well ive got a 406 2.0 GLX ( D9 ) petrol on a Vplate thats giving me jip

Ive read the thread on the fan relay and resisters which ive changed and found one to be proper crook. ive even changed the temp sensor on the thermo housing.

thought that had cured it... till yesterday

The car will drive just find for about an hour but the temp never really goes above 70c. after an hour it bloody starts again... i.e. when im coming off the motorway.... if i coast down and let the rev gown to about 1k then it stops till to put my foot back on the gas..... it also clears when i disconnect the battery and start her up again!!!!!

temp gauge goes out when i start then slowly creeps to 90c.

water pump is working.. it gets hot and cold ( i can feel the return pipe get hot )

fans work in both speeds now....

Car drives perfect besides this....

Any ideas??? its driving me bonkers..... is there any other temp sensors or relays? what about this BITRON unit???

I really can't afford to take it to a pro so i need to do as much as i can myself....HELP?????

the bitron thing afaict is a little ecu for the fans. It lives in the passenger side front wheelarch. Not sure what its relationship is with the temperature gauge however, the wiring diagram in the haynes may help.

ill have a look.. what temp should the car be running at? could the thermostat be up the wall?? when i replaced the sensor i didnt get at coolaint come out like that haynes manual said would... could it be clogged up and wide open?

The gauge might be duff but I doubt if the STOP light would come on for an engine that's running too cool. Did you bleed out all the airlocks after you changed the sender? It could also be worth flushing the system.

I did a sensor replacement of my D8 recently. There are 3 sensors , one is for the ECU to calculate fuel mixture and the color should be green if i'm not mistaken. and the maroon out of other two sends to the BITRON unit to start the fans and the blue one sends to the gauge. I had a problem of late engaging of fans at 98 degrees. So i changed all 3 sensors. Stil i couldn't get the car back from the repair point so its too early to comment whether my problem solved or not. I replaced the water pump, the reservoir tank, reservoir cap, couple of hoses, radiator now what is left to play with is the BSI unit which MJ mentioned.

no BSi on the D8, and the D9 has a completley different cooling fan system to the D8, the fan is triggerd by the engine ECU

no water at all came out when i changed the sensor.... maybe that could be it? could it be air locked etc? hense the erratic temp?

jameslxdt wrote:no BSi on the D8, and the D9 has a completley different cooling fan system to the D8, the fan is triggerd by the engine ECU

now thats news and now i got to findout what that black box does sitting nicely on the passenger side wheelarch.

tboy113 wrote:no water at all came out when i changed the sensor.... maybe that could be it? could it be air locked etc? hense the erratic temp?

I'd imagine that'd give you all sorts of problems, although the question is why - did the previous owner leave it like that for you or is there a leak?

Try bleeding the system, like it says in Haynes, but if you experience any difficulty bleeding it (i.e. nothing coming out of the bleed screws), you'd be needing to flush the system. You might be better off just using water to fill it as this point too as I'd advise changing the whole lot once you know the system's ok.

the car hasnt lost any water.. ive checked the level in the expansion tank. saying that... when i open it even when hot there isnt any pressure hiss when i open it. i think ill flush the system and give it a good clean. anyone recomend any cleaning agents? or shall i run on just water for a few days then replace with anti freeze?

what temp should it be running at? what symptons would an air lock give?

tboy113 wrote:what temp should it be running at? what symptons would an air lock give?

On my ZX 1.9TD the symptoms I got from an airlock in the cooling system was the temparature lokked normal, until the head blew and all my oil was sprayed down the M11

tboy113 wrote:the car hasnt lost any water.. ive checked the level in the expansion tank. saying that... when i open it even when hot there isnt any pressure hiss when i open it.

I'm fairly sure any petrol car should have a considerable amount of pressure in the coolant system when hot, which would mean removing the expansion tank cap would result in a small fountain of coolant, so if you're getting nothing either you've got very little coolant in there or yer thermostat is buggered i think.

You might not see a drop in the water level if the water's being replaced by air. Even if the thermostat's stuck, the system should pressurise, so I'd suspect a substantial amount of air in there. By all means, use a tin of radiator flush. Anything with Holts or Wynns on it will probably do the trick.

Cool.. thanks.. ill give it a go this weekend.. ill try bleeding it 1st then ill replace the thermostat.. its only £11 from the main stealers.

Its going between 65c and 70c on the motorway and 90c when sat in traffic. seems to moan when i go down hill!