20 Oct 2018, 15:10
So recently I had to replace my battery as it had dead cells.
On hooking up my new battery the fans immediately came on without the ignition on or anything.
Now I have fitted a few years back David McKeen's solid state fan and fan fail relays as well as a button to bypass the otterstat. Occasionally I have lent on the button by accident but it seemed off. David's fan relay also has a 'run on' feature that will keep the fans spinning after you turn off the ignition for a minute or so.
With both of these in mind I waited a minute or so to see if the fans would stop on their own.
Then I smelt the distinct wiff of electrical burning from my relay compartment!
The fan relay was red hot and smoking. I quickly shut down power and let it cool and when I pried the relay out it looked like this:
I found my spare, original fan relay and tried it. Everything seemed fine, the fans did not come on without the engine and the relay did not get hot.
I started her up and left her to idle for a while and when she got up to temp the fans kicked in and all seemed well. The only odd thing was that my fan override switch no longer seems to force the fans on, although I could hear a 'click' coming from the relay compartment.
I vowed to investigate further and contact David McKeen to see if he had any ideas.
A few days later I needed to take her for an MOT. On the drive over there I was stuck in some traffic but the fans came on and the temp gauge read normal, in fact when I pulled up to the garage the fans were on. But at some point during testing, with the engine left running, they turned off and stayed off -resulting in the engine starting to overheat and dumping red-hot water out of the expansion tank overflow.
I cut the power using my battery isolator and checked the relays, seemed fine, not hot. I also in desperation took apart my fan override switch. On re-connecting the battery I wiggled the fan switch a bit and the fans came on! We topped up the water and I made a break for home.
A few miles down the road though I hear a click from the relay compartment and the fans stop again. Toggling and wiggling my fan switch resulted in a audible click from a relay but the fans not turning on. My temp started to climb when in traffic but was able to keep moving and avoid anymore overheating.
So what could be going on? Could my otterstat override switch be dodgy which melted the solid state relay? was the solid state and spare realy both faulty or is something killing them? Is my otterstat up the duff?
Any suggestions on where to look appreciated!
On hooking up my new battery the fans immediately came on without the ignition on or anything.
Now I have fitted a few years back David McKeen's solid state fan and fan fail relays as well as a button to bypass the otterstat. Occasionally I have lent on the button by accident but it seemed off. David's fan relay also has a 'run on' feature that will keep the fans spinning after you turn off the ignition for a minute or so.
With both of these in mind I waited a minute or so to see if the fans would stop on their own.
Then I smelt the distinct wiff of electrical burning from my relay compartment!
The fan relay was red hot and smoking. I quickly shut down power and let it cool and when I pried the relay out it looked like this:
I found my spare, original fan relay and tried it. Everything seemed fine, the fans did not come on without the engine and the relay did not get hot.
I started her up and left her to idle for a while and when she got up to temp the fans kicked in and all seemed well. The only odd thing was that my fan override switch no longer seems to force the fans on, although I could hear a 'click' coming from the relay compartment.
I vowed to investigate further and contact David McKeen to see if he had any ideas.
A few days later I needed to take her for an MOT. On the drive over there I was stuck in some traffic but the fans came on and the temp gauge read normal, in fact when I pulled up to the garage the fans were on. But at some point during testing, with the engine left running, they turned off and stayed off -resulting in the engine starting to overheat and dumping red-hot water out of the expansion tank overflow.
I cut the power using my battery isolator and checked the relays, seemed fine, not hot. I also in desperation took apart my fan override switch. On re-connecting the battery I wiggled the fan switch a bit and the fans came on! We topped up the water and I made a break for home.
A few miles down the road though I hear a click from the relay compartment and the fans stop again. Toggling and wiggling my fan switch resulted in a audible click from a relay but the fans not turning on. My temp started to climb when in traffic but was able to keep moving and avoid anymore overheating.
So what could be going on? Could my otterstat override switch be dodgy which melted the solid state relay? was the solid state and spare realy both faulty or is something killing them? Is my otterstat up the duff?
Any suggestions on where to look appreciated!
Whilst the OE otterstats are rubbish I think the upgraded version along with an emergency by-pass works fine IMHO.