engine overheating

paulb · Post by **paulb** » 18 Jun 2005, 17:53

I have recently become an owner of a xantia 1.9td mk2 1999. which tends to overheat because the cooling fans are not kicking in. I noticed that when i disconect the temp sender switch on the thermostate housing 1 fan starts up. have replaced this switch. but no joy. can anyone sugest what could be wrong.

PeterMann · Post by **PeterMann** » 18 Jun 2005, 20:39

May be the bitron unit. Very little known/published about what it does and how it works, but it does seem to have a role in controlling the switching of the radiator fans. Apparently, there are more than one version of the bitron unit, but borrowing one briefly from a similar model of Xantia may pinpoint the problem. On my 1994 2.0i, the bitron is under the black cover behind the battery.

mezuk04 · Post by **mezuk04** » 18 Jun 2005, 21:24

Ok so things may be quite a lot different when it comes to the Xantia than a zx but search the forum for the same type of thread (engine/radiator fans not kicking in??) from myself and Wilkobob....cant remember exactly what was the problem but it took a while to get mine going....only the 1 fan since its a straight diesel....i love it now when the fan kicks in....its a beautiful sight to behold

citronut · Post by **citronut** » 19 Jun 2005, 00:04

there are allso some relays behind grill in between both of the fans,sometimes the conector get a bit hot which is due to bad conections,the air/con if fitted can afect rad fans regards malcolm

wheeler · Post by **wheeler** » 19 Jun 2005, 06:09

if only one fan kicks in when disconecting the brown temp sensor on the thermostat housing then either the other fan motor is faulty or its relay is missing a feed most likely due to corrosion in the relays or their plugs as mentioned above.

Richard Gallagher · Post by **Richard Gallagher** » 19 Jun 2005, 10:37

Take a look on www.peugeotlogic.com there you will find a full explanation with diagrams on how the fans work on a Pug 306, the same system as a Xantia.

oscarloco · Post by **oscarloco** » 20 Jun 2005, 20:37

I will suspect of a fan motor. Since they kick in first at low speed in series, if one is faulty then both won't start. Only when the temp goes higher they are connected in parallel and both go to high speed. At that point, the healthy one will start.
Also check the thermostat. I had the same problem on my ZX, one faulty fan and the thermostat and the car overheated.

James.UK · Post by **James.UK** » 20 Jun 2005, 22:26

Hi MezUK both the ZX 1.9D auto's I am familiar with have two fans.
Maybe only auto's have two fans though.

jeremy · Post by **jeremy** » 20 Jun 2005, 22:32

I'm sure our ZX 1.9D has 2 but it also has a towbar and an oil cooler for the engine.
They hardly ever come on even in this weather - just like my TD BX.
jeremy

paulb · Post by **paulb** » 26 Jun 2005, 17:50

thank for everybodys help. i have now solved the problem. the feed from a relay to the control unit wae broken Earth return. once again thanks to you all