over heating fans not working

[rusty]

Hello everybody i'm new on here

I have had a peugeot 406 2.1 td glx(has air-con) for about 3 weeks I have started to think this car is cursed after only 3 days the cam belt almost snapped now the car is overheating, its ok while moving. I can start the car on the drive and leave it for an hour and temp is ok but if I drive the car then get cought in traffic within 5 mins temp shoots up and it starts dropping coolant from a leak that appeared on the bottom hose somewhere as soon as temp drops below 90 the leak stops (cant tell if its bottom hose or from the rad )The fans dont work the drivers side fan will work if I wait for car to warm up then set the fan off by hand the passenger side fan was very stiff this has now been solved something was catching on it. From reading some threads about this sort of problem I have half figured it out I need to take a wire off bitron sensor and fans should start to check relays and fans for the motors the problem is i'm not a mechanic at all does anyone have any photos of where i will find the wire for bitron sensor and are they any other ideas to the problem may be ?

many thanks rusty

[rusty]

can i just add yesterday i went to the coast got all the way there without any problems 2.5 hours driving at average 60-70 mph no high temp no leaking coolant on the way home hit traffic within 5 mins temp shot up started leaking coolant but didnt over heat pulled over before it got too hot as soon as temp dropped i topped coolant up and crawled through nearly 50 mins of traffic without any problems

[citronut]

first thing i would try is bleed to coolant system thoroughly,
also i might be wrong here but do the fans run/try to run if you switch the air con on as i belive they should,

the other thing to check is the three relays in under the triangular cover between the two fans to see if the terminals have gone green/corroded, if so clean them up and re/check fans,

the usual cause for fans being stuck/hard to turn by hand is something else was at fault to stop them working, so they seized up with lack of use,

regards malcolm

[spider]

Agree with above, carefully bleed it, airlocks can cause overheating (and engine damage) although I'd expect in some cases coolant to be ejected in that case but you never know, airlocks are funny things in their behaviour.

Check the relays under the panel at the front. Caution: The fans are *permanently live* so keep your fingers well clear or disconnect the battery first ideally. Watch out for bits (stones etc) flying out too, unlikely but you never know. Corrosion in the relays or connectors can cause this non fan issue.

If I remember correctly (was a long time ago now) one relay for each fan and an overheat (switches them on, see text below) one in the middle.

Malcolm is right in that if the AC is on a fan should run, although if you unplug the bitron sensor in the thermostat housing (brown one I think) after about 5 to 10 seconds the fans should come on anyway, as it regards a missing signal from this sensor as a potential overheating condition so will switch the fans on.

The water leak is probably a pinhole in the radiator or possibly the oring seal in the bottom hose, difficult to say without seeing it though.

[rusty]

i have flushed and bleed the coolant i think the leak is a oring seal on bottom hose but have confirmed this by the time it cools enough to look the leakhas stopped

i have discnnected the brown sensor the middle relay clicks but not the other 2 ? i have swopped the relays round and the middle one always clicks when brown sensor wire pulled so what do i need to do next any idea ?

thanks for replys so far

[spider]

Its a good sign its clicking as its signalling the overheat if nothing more.

Check main fusebox in engine bay, examine all fuses as the fans are fused here if I remember correctly.

Are the relay pins clean, ie: they've not gone green! and their sockets too.

If you are able to, (don't do this if not sure) you can carefully open the relay itself and check the internals are not corroded. Check all three.

[rusty]

thanks for speedy reply

now i'm not electrical minded at all so bear with me. the relays (the green block that pulls out ) i have 7 of these and they all click in the middle socket, i assume that means all the green block i have work fine ? all the sockets look very clean i have given them a little squirt of wd40 (as another post advises)

do you which fuses they are ?

mny thanks

[spider]

The relays will be just those three in between the fans.

The box on the right hand side near the battery (might be two box's) one will contain some largeish fuses, you just need to check they have not blown.

[rusty]

got the 3 relays but i have 7 green blocks to swop around with

so its the large ones i need to check ? had a look at the little ones and they appear fine

[spider]

I'm not sure what you mean by 7 green blocks.

The fuses to check are in the engine bay area, there's a fusebox with just some large fuses in it if I remember correctly.Not the 'normal' size ones, they are quite a bit bigger (same plastic coloured design though) , then fan feeds are probably fed through these.

I don't have access to any technical data today so I'm trying to remember from a few (more than a few) years back.

[rusty]

update fuses have been checked there was one fuse that had blown i've replaced that but still nothing.

ive been proding and tinkering pulling bits off that i have no idea what they are and checking connections but nothing still only clicking on the mddle replay when brown sensor is pulled

[rusty]

think i might be getting somewhere the fan that was not working started working run for about 30 seconds then blow the fuse

[spider]

With the battery disconnected (or a screwdriver if you don't want to disconnect the battery, don't put your fingers in it!) Is the fan stiff to turn, compare it to the other one (assuming you have twin fans)

What rating or colour was the fuse that blew ? , I'd suggest replacing it once to see if it blows again, you might be lucky and if it was slightly seized it ran long enough to hopefully un-seize it. If it does blow again then further investigation is needed.

[rusty]

the fan is stiff to move by hand i have tried another fuse 40 and even tried a 50 fuse both blew the fan now only works intermitantly.

would the stiff fan cause fuse to blow it appear to be strugging t get going speeds up then slows down

[spider]

Yes, I'd say that's the cause then as its partly seized.

A larger fuse is not a good idea as the current draw from a seizing fan is higher (hence fuse popping), so you risk overloading the wiring.

If you can get the fan(s) out for examination you may be able to sort them out alternately a replacement fan(s) unit. As above I don't have any tech data to hand today, I don't think the bumper has to come off to get them out, possibly move the rad and the aircon condensor a little bit without disconnecting their pipework.


As a completely random sidenote, Alternative current motors actually drop in current use when they are strained (vaccums etc when you block the pickup piping) although a semi seized fan is still the likely cause in your case with a dc powered fan.

They need to come out to be checked or replaced really.