Overheating ECU problem?

[Tuska]

My fans have stopped working and she overheated yesterday. No obvious fuse problem.

Warren at Topcats says that it could be the ECU. Is this right????? Any advice or ideas would be appreciated.

[Trooper2]

Most fans are run off of a relay, I'd look there next.

[T88CAN]

The ECU on the Tuscan looks after soughts of unusual things, the toaster did not pop up yesterday so i blamed that

The ECU takes a signal from the water temp sender and starts and stops the fans IIRC I would check out the sender, the fans are on TWO different circuits so if one fuse blew the other fan would still work, the chances of both fuses blowing at the same time???, better check to be on the safe side

[Tuska]

Both fuses are ok, and the relay seems fine. I will have a look at the sender over the weekend.

Looks like i'm in for a trip up to Topcats and a plug into his laptop. Oh the joys of owning the best looking car in the world.......

[basil brush]

Sounds like it may be your temp sensor. Have you noticed any rough running/drop in tickover speed? Sender is about a tenner and an easy diy job.

[Tuska]

Thanks for your replies.

I took the main bonnet off and ran the car up to temperature. At about 80 degrees coolant fluid started pouring out of the filler cap. (it seems to have a pressure release system of some sorts??? or is it just knackered?)

Anyhow, the fans never cut in. I had a mulitmeter on the cables and they never recieved any power. Fuses and relays are good so the temp sender is the next thing to check. Can someone please tell me which is the temp sender?????

Also does anyone have any information about my leaky filler cap????

[dodgyviper]

Just had a similar prob with my chim. Overheating and a v high idle speed. Also the heater stopped working

The fan never cut in either.

Had a leaking radiator and coolant level was way down.

I'd check coolant levels next.

>> Edited by dodgyviper on Sunday 13th February 17:43

[Trooper2]

Tuska said:

Thanks for your replies. I took the main bonnet off and ran the car up to temperature. At about 80 degrees coolant fluid started pouring out of the filler cap. (it seems to have a pressure release system of some sorts??? or is it just knackered?) Anyhow, the fans never cut in. I had a mulitmeter on the cables and they never recieved any power. Fuses and relays are good so the temp sender is the next thing to check. Can someone please tell me which is the temp sender????? Also does anyone have any information about my leaky filler cap????

Hi Tuska, being from the U.S. I'm not familiar with the layout of the Tuscan, however the water temp sending unit would need to be screwed into a water jacket some where. So it could be in the block, head or intake manifold. They generally look like a small sparkplug plug with the ceramic bit cut off. They usually have one wire plugged into them but could have 2. There also might be more than one on a computer controlled car. Hopefully another owner of a of a Tuscan will give you exact location.

[basil brush]

There are two temp sensors on the drivers side of the engine under the air box. The ecu sensor is the back one of the two and has a push on plug. The front one with the two fixed wires coming from it drives the gauge.

[yzf1070]

Tuska said:

Thanks for your replies. I took the main bonnet off and ran the car up to temperature. At about 80 degrees coolant fluid started pouring out of the filler cap. (it seems to have a pressure release system of some sorts??? or is it just knackered?) Anyhow, the fans never cut in. I had a mulitmeter on the cables and they never recieved any power. Fuses and relays are good so the temp sender is the next thing to check. Can someone please tell me which is the temp sender????? Also does anyone have any information about my leaky filler cap????

My manual advises that the first fan cuts in at 90C the second at 92C. I have read other threads whereby S6 owners have had to replace the temp sensor due to same fan/s issue.
The most likely reason that your fluid started coming out the filler at 80C is because the thermostat opens around 82C. Up to this point the coolent does not circulate via the radiator. The thermostat when open provides the route thro the radiator. The filler cap should be pressure regulated to stop normal operating temp fluid from spilling over. You opened this and when the thermostat opened the expanded hot fluid spilled over. If your cap is leaking it could be faulty or worse it could be that combustion gases are making their way into the coolant system (head gasket). A dealer should be able take a sample of your engines coolant fluid and detect for carbon monoxide contaminants.

[NCE 61]

Tuska said:

Thanks for your replies. I took the main bonnet off and ran the car up to temperature. At about 80 degrees coolant fluid started pouring out of the filler cap. (it seems to have a pressure release system of some sorts??? or is it just knackered?) Also does anyone have any information about my leaky filler cap????

If you over fill the coolant you will also get this. Filling up to 1cm above the filler neck this can be too high.They do just seem to find there own level ie blow out the excess through the pressure release cap prior to the thermostatic valve opening.

As for the fan's not coming on if fuses/relays are ok the water temp sender will possibly be the problem.

Nick