Cooling fans not working correctly

Ramocc · Unread post by **Ramocc** » 10 Aug 2009, 15:27

Today, after stopping the car for only a few minutes, it refused to start again. Wouldn't turn over, just clicked. After a few minutes, it starts up, but the turning over seemed a bit "sluggish". I figure the engine overheated, so after driving home, I left the engine running, opened the bonnet and listened for the cooling fans, which are on. However, the moment I turn the ignition off and take the key out, they go off completely. Putting the key back in and turning it to just before ignition and they go back on again.

After reading various other threads here, I checked the four relays (three between the fans and one near the battery), all the fuses near the battery and what I think are the relevant ones in the cabin, and both fans, and they are all fine. It actually seems that the temp sensor that triggers the relays is not working when the key is out, which I don't think is the correct behaviour. Btw, my car does not have aircon.

Does anyone know anything about this? Whereabouts is the relevant temp sensor, and how would I test it?

Just to add, the STOP light hasn't come one at any stage.

Sid_the_Squid · Unread post by **Sid_the_Squid** » 10 Aug 2009, 15:38

Your right its not the correct behaviour, I also have this issue with 1 of my current Xantia's, checking the handbook it says the fans are suppose to operate with the ignition off for a short time.

However this seems to be a common problem, which as far as I can tell is not worth bothering yourself about, provided your cooling fans work normally all should be fine.

I started a thread here a while back asking the same question as you, is this an issue? From the responses received seems some peoples Xantia's do it some don't, the ones that don't, seem not to suffer from it.

Sluggish starting, sure its not the battery?

Ramocc · Unread post by **Ramocc** » 10 Aug 2009, 15:49

I don't think it's the battery, it was replaced recently enough, and it went from not turning over at all, to starting sluggishly, kinda the opposite to when the battery dies, I think.

I wouldn't have worried about it, or even noticed it, if it didn't seem to make a difference to the car starting up. After testing the relays and stuff, I tried running the engine at 1500rpm until the fans kicked in, then turned the engine off but turned the key back to just before ignition. After waiting till the fans cut out (which took a good 10 minutes), I took the key out, left the car for a few minutes, like before, and started it again. This time, it started fine.

I forgot to mention earlier, that when I did get the car to start again (the first time, not after leaving the fans on), the temp needle was around 95, which was higher than it was when I had turned it off. So I think the car is overheating after the engine is turned off, and I don't want to risk damaging the engine by ignoring the problem.

Sid_the_Squid · Unread post by **Sid_the_Squid** » 10 Aug 2009, 16:10

Afraid I don't know anything more about the issue that what I've already posted, I think Jim has some wiring diagrams, perhaps he will be along later to post them, wiring dig's don't mean much to me sadly.

I'll be interested to see where this thread goes, I've not worried about the issue after seeing just how many people have the 'problem' without any ill side effects. Because of this I would suspect your bad hot starting is not to do with the fans not cooling your engine, but some other fault that is being hilighted when the engine is hot.
Is your oil in good condition/appropriate spec? What condition is your cooling system, i.e. when was it last flushed, is the antifreeze to water ratio correct? I apologies if these questions sound patronizing, just trying to cover all areas

A battery that's not powerful enough i.e. not enough amps, would cause sluggish starting even if it was brand new, although you would more likely see this when the engine was cold.

I'm 100% sure its not the 3 fan relays, I've changed all mine with the official relays from Citroen, if anything its probably an issue with the Bitron unit, which controls the fans, but I'm speculating here.

Ramocc · Unread post by **Ramocc** » 10 Aug 2009, 16:21

No worries about the questions, I didn't even think about it being an different problem.

I've changed the oil since I bought the car, it was pretty filthy at the time. I didn't get a chance to run some oil flush through it at the time though, so that might be worth doing.

I haven't changed the coolant at all, but it looks ok (kinda greeny, no rust/sludge). I've already bought deionized water and antifreeze and a new thermostat, to change once I got a chance.

I'll try changing the coolant and oil so, hopefully that will solve the hot starting problem.

Unread post by **CitroJim** » 10 Aug 2009, 16:24

Firstly, all my Xantias cut the fans when the ignition is off but there is a little confusion here as I've seen references to time for fans to run after ignition off, almost as if you can set a paramater somewhere in an ECU but have discovered no more. Maybe it's something for a different market somewhere.

Secondly, it is normal for the coolant to initially get hotter when the engine is stopped. The water is no longer being circulated under force by the water pump but it is still being thermo-syphoned aroud the system. It is moving more sluggishly but still extracting heat from the hot places in the engine but cannot dissiplate it well as there is no airflow through the rad. All engines do this but it is perhaps more noticeable on the Activa as the cooling system is, at best, marginal.

It is of no concern. The Activa engine is a tough beast that runs hot at the best of times and this getting hotter when stopped causes no ill effects. Under some circumstances, the coolant can actually get hot enough to boil after a stop.

I often allow the engine to idle after a run until the fans cut out naturally. This should not take 10 minutes though unless you have a deteriorated rad.

As for the sluggish start, that's most likely the starter motor; they don't like being hot and it will be under the circumstances you describe. Is is still Ok when starting from cold? What it won't be is anything wrong with the engine. Provided the oil is good and the coolant temperature is not silly hot, seizure is almost unheard of these days.

Ramocc · Unread post by **Ramocc** » 10 Aug 2009, 16:35

The starter motor, yet another thing I didn't consider.

It starts fine from cold, although today's the first time it didn't start when hot. Should the starter motor be getting that hot? Maybe it's is on it's way out?

I didn't run the engine at idle for 10 minutes, I just turned the key so the fans came on, but with the engine off. Maybe that's why it took so long.

I'm quite relieved to hear that it's not the engine. Thanks Sid and Jim.

Unread post by **CitroJim** » 10 Aug 2009, 16:44

Ramocc wrote:Should the starter motor be getting that hot? Maybe it's is on it's way out?

It does get pretty hot from both being in physical contact with the block and in the direct path of hot air from the rad, especially with the fans running and pushing hot air through at a rate of knots. Have you ever noticed how much hot air is blowing around under the car if you stop with the fans running and open the door. It's almost like being in a fan oven on a hot day

If the starter works fine when cold than I'd say it was not on it's way just yet. Give it another few tests when the engine is really hot and the fans are running to see if the problem is repeatable.

Sid_the_Squid · Unread post by **Sid_the_Squid** » 10 Aug 2009, 16:47

Thanks Sid and Jim.

Happy to help

Ramocc · Unread post by **Ramocc** » 10 Aug 2009, 16:55

CitroJim wrote:If the starter works fine when cold than I'd say it was not on it's way just yet. Give it another few tests when the engine is really hot and the fans are running to see if the problem is repeatable.

Will do, thanks.