205Si intermittent overheating problem

L

Langers

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Fellow Frogger
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Jul 1, 2003
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All,

My 205 Si has decided to start misbehaving by intermittently overheating. The most recent episode was on Sunday when it was 30+ degrees, driving through Balmain, which Sydneysiders will know is congested and slow going. The temp needle started its march towards the red line but thankfully traffic cleared and I had a good run across the bridge etc which cooled things back down again.

The overheating has happened about 3 times in the last year – the only explanation I can think of is the cooling fans not kicking in. A couple of times I have cut the engine and turned the ignition back to accessory mode where you’d expect to hear the fans running, but on these occasions there was no sound.

How does the cooling fan system work on a 205 Si? I’m familiar with older cars (fan belt) and newer cars (fully computer controlled fan modules), but I suspect the 205 is somewhere in between? Are there any popular fan upgrades? I’m happy to shell out whatever it takes to be able to have the car run as it should in the 35+ degree heat that we will no doubt experience this summer.

Appreciate any advice on where to start looking.

Cheers
 
Relays!!!

Langers said:
Research shows that these are a direct replacement.

http://www.daviescraig.com.au/Therm...__SHORT__12_VOLT___PART_No__0147-details.aspx

Is there any way of diagnosing whether it's the relay, fan motor or temp switch at fault?
Click to expand...

The fan relays in the plastic box at the front give problems (from memory the green ones), two of mine (originals) crapped themselves (burn marks on case). The connections also some times corrode up. Get some new relays if you doubt them (Repco).

Good Luck :)
 
Hmm, not really sure what to doubt at the moment - but at least the fan relays are a cheap / easy fix if they are the problem.

Thanks for the advice!

As a general observation, the fans do seem a bit on the weak side - probably worth replacing the relay(s) and then the fans at a later stage as preventative maintenance.
 
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GRAHAM WALLIS said:
Connect 12 volts directly to the fans and see if they work.
Click to expand...

Could do... but unfortunately it's an intermittent problem - so I suspect they would run, and then one in every, say, 15 drives they would not run. Maybe there's a dead spot on the commutator?
 
OK, so experienced the same issues again today. I suspect it's not the fans, as when the car was overheating, neither of the fans were working - seems to me it would be a bit strange to have both fans fail intermittently at the same time, and start up again at the same time.

So, my understanding of the system is that there is a thermal switch connected to a relay which is in turn connected to the fans. I would have thought that the termal switch would either work or not, so next port of call is the relay(s).

Which of of the below (or two) is the cooling fan relay(s)?
 

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Fan relays

I think the two centre ones, they have fairly heavy gauge wires running to them, (the fans draw a bit of power).
Also check the fuses in the little box beside the larger relay box.
The other thing that fails (gives trouble) is the radiator sender switch (screws into the radiator almost immediately below the smaller fuse box.

Thats the end of my knowledge with the fans :).
 
There are three relays to control the two fans. When on low speed the fans are connected in series. When on high speed the fans are connected in parallel.

There is a sensor in the LH side of the radiator which turns on the relays. Remove the connector. If you connect two of the wire (not sure which two) the fans should go to low speed. If you bridge out all three wires the fans should go to high speed.

I have a schematic if the above doesn't help solve your issue. ie it's more than likely that the sensor has failed.

A new sensor is approx. $90. I think Adrian still has an Si in his front yard. You could offer him $40 for the sensor?
 
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Thanks all. Just before I book the car in with the mechanic (thank god for NRMA roadside assist - towing would be VERY expensive otherwise!), does it make sense that the sensor would fail intermittently?
 
HOT pug

Langers said:
Thanks all. Just before I book the car in with the mechanic (thank god for NRMA roadside assist - towing would be VERY expensive otherwise!), does it make sense that the sensor would fail intermittently?
Click to expand...


Purchasing " A new sensor is approx. $90 " would have to be far more economical than taking the car to a mechanic. The mechanic will charge more than this per hour + the part.

I think that the sensor could "fail intermittently".

Price a new sensor from Repco, it is only a matter of pulling the electrical connector off and screwing the sensor out of the radiator with a shifter. If (when the car is cold) you remove the old sensor and quickly refit the new one there will be no need to drain the radiator.

Good luck :)
 
Interesting, does a place like Repco have the ability to order Peugeot parts? Or are you implying that the sensor would be generic?

No need to bleed the coolant system after replacing the sensor?
 
Generic parts...Or why is my car so expensive to service?

Langers so many parts are generic it isn't funny, a Bosch sensor is but just a Bosch sensor until it becomes a Peugeot part then the part rockets up in price.
Repco/Bursons and proper trade supply outlets usually have a cross reference for items that have a common source. Supercheap are to be best avoided as they like to limit their range to particular suppliers to keep costs down/best buy price (them, not us!).
A quick call is all that's needed and a bit of detective work with the 'smoke in wire' system should sort it out.:cheers:
 
Well EAI has the below parts listed.

Radiator Fan Switch
P126414 RADIATOR FAN SWITCH-P505/205 2 PIN 88/79
P126417 RADIATOR FAN SWITCH-P505/205 3 PIN (=I)
P126445 RAD FAN SWITCH-P205/405LexcMi16-3PIN(III

http://www.eai.net.au/p205parts5.html

Any idea which one is suitable for the Si?
 
So EAI has them in stock, cheaper than $90, but they can't advise which one is suitable for an Si. Hmm.
 
Absolutely zero chance of getting to Repco during the week, and my local one doesn't seem to like answering the phone.
 
So I'm going to pull the car apart this weekend to find out what type of sensor I have. Does anyone have any intel on which connections I need to bridge on the plug side to test low and high speed fan functionality?
 
You can't hurt by experimenting with a paper clip etc. , as per my reply above.
 
Will give it a go... may need to rig up something a little more semi-permanent to get through the weekend. Can't hurt too much to have the fans permanently on low speed, can it?? (thermostat would maintain at least some heat in the engine)
 
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