Overheating

mds141 · Post by **mds141** » Sun Jul 10, 2011 4:38 pm

After a run out to the car wash left the engine idling on the valver whilst i did some citrobics. Stop light came on and water temp gauge through the roof with red light on. Fans didn't kick in at all. Coolant levels are fine. What is next course of action. Where are electrical connections to fans could it be the thermoastat? Temp is fine whilst car is in motion. Cheers Mark.

Gibbo2286 · Post by **Gibbo2286** » Sun Jul 10, 2011 4:46 pm

First place to look is the fan switch, down the side of the radiator, pull the wires off and join them together, if the fans run then it could be either the switch or just dirty connections, give the connections a good scrape to get off any green grot and reconnect them then try your citrobics again to see if it's sorted if not replace the switch. Most motor factors can supply the switch.

If the fans don't run with those wires connected together it's likely that the fans have died but that's a very rare occurence. Gibbo.

mds141 · Post by **mds141** » Sun Jul 10, 2011 4:50 pm

Cheers Gibbo out the door now! Do the fans run with a relay or just a fuse? Cheers.

kiwi · Post by **kiwi** » Mon Jul 11, 2011 12:11 am

First place you should look is the FUSES

In the fuse box located in the passenger footwell under the dash.

I had this problem blamed everything else ended up being a faulty fuse. Ironically the replacement fuse was also at fault.

Matt H · Post by **Matt H** » Mon Jul 11, 2011 12:06 pm

I had this problem a few months back when I got my 16v back on the road. It turned out to be the plug going to the switch on the rad. If I held it in a certain position the fans would cut in. I cleaned it all up and it improved but still need to change the plug, although I couldn't find one that looked right...

If I put the heater on the fans barely ever come on anyway

How quickly did the temp gauge go through the roof? It could be a dodgy sender?

Kitch · Post by **Kitch** » Mon Jul 11, 2011 8:28 pm

Citrobics are nothing to do with the hot running, it\'s the fact you\'re sat still.

Like has been said, check the fan\'s working first. If it is, then connectors to switch or switch itself could be iffy. The fan is the likely culprit.
Otherwise it\'s worth getting an infared thermometer and check the temp of all the hoses under the bonnet when it\'s at running temp. Aside from the obvious differences like the rad hoses and heater hoses (if your heater is running) this will highlight any blockages in the system, or any areas where the system isn\'t working as it should (ie if you\'ve got all pipes at 88c and one at 30!).
A partially stuck thermostat could cause that, and it could be the engine is able to overcome it on the move as the air is cold and the coolant is pumping faster, so theres less heat soak.
If there is a massive variance at the rad, check it\'s hot all over. Cold spots could indicate blockages or air locks (if they\'re at the top).

mds141 · Post by **mds141** » Mon Jul 11, 2011 10:14 pm

Thanks for response guys. Cleaned the terminals to the fan[only one on the 16v] and checked fuse still no action from the fan. Is the switch on the radiator itself?

Post by **Defender110** » Mon Jul 11, 2011 10:25 pm

Yes the switch is on the radiator half way down one side, Take the wires off the switch and bridge them out with a short piece of wire to eliminate the switch.

mds141 · Post by **mds141** » Mon Jul 11, 2011 11:45 pm

Tried it again still no fan cutting in despite temp gauge entering the red zone. However noticed not much heat coming through the heater despite being on max. Thermostat?

rayfenwick · Post by **rayfenwick** » Tue Jul 12, 2011 1:15 am

My money's on the connector... my CX 22TRS caught me out with that 30 mins before the MOT... thank goodness for radweld!

mds141 · Post by **mds141** » Tue Jul 12, 2011 1:25 am

Don't want to risk failure en route to the National. Will see if Dave Ashworth can have a look. If not will have to come to the National in the DS3. Not a proper Citroen i know.

kiwi · Post by **kiwi** » Tue Jul 12, 2011 8:03 am

Has the fuse been checked? Replaced and then replace again. Might sound OTT but I can prove that one.

Oh btw, was messing around with thermal Image Camera courtesy of the Fire Brigade. The engine looks pretty...erm cool

Post by **Tim Leech** » Tue Jul 12, 2011 8:40 am

When did you last change the coolant, Maybe worth doing, its a faff to get the airlocks out but worthwhile, also whilst your at it take the radiator outa nd flush it and fit a new thermoswitch (fan switch)

Post by **mat_fenwick** » Tue Jul 12, 2011 9:57 am

Roverman wrote:When did you last change the coolant, Maybe worth doing

That wouldn't stop the fan operating though. If you short the connector for the fan switch as suggested by Kevan and Gibbo (not sure whether you have or not?) that bypasses the usual culprit and checks the rest of the circuit (including the fuse!) If the fan does not spin when you do that it's time to look elsewhere - but it's a very simple test to do. The engine doe not need to be running to carry this out.

A thermostat problem wouldn't stop the fan from coming on. You've confirmed that the cooling system is fine in normal operation, just something stopping the fan from working.

Gibbo2286 · Post by **Gibbo2286** » Tue Jul 12, 2011 10:11 am

It seems to me that you haven't actually got an overheating problem just a gauge mis-informing you. I suggest you change the gauge sender it's not an uncommon fault, not expensive and available from motor factors. Gibbo.