Ibiza Problem

[bitza]

OK Guys I need some help here. I have a 1999 Seat Ibiza Cupra 2.0 l 16V. The temp gauge tells me I am overheating but my infrared thermometer tell me its not. I've changed the water pump and thermostat, flushed the radiator (it seems to flow just fine). I have now changed the the temp gauge sender unit (was brown in colour, now replaced by Black with Blue band according to my Seat dealer). But the problem still continues. When the gauge shows hot and you rev it up to 3000 plus the gauge temp moves to a lower gauge value, indicating more water flow and so cooling. The gauge then jumps up after the rev, faster than the temp of the water would reacte in my opinion.

Is my radiator blocked enough to over heat at low engine speeds, and not at higher engine speed. Or is my gauge gone? Does anyone have any history here, any help would be greatly appreciated?

[Golf Loon]

I`d suspect the sender. Should be replaced by one the same colour I`d have thought.

Is the car actually overheating? does it feel hot, or smell like she is boiling? does the light always come on, or only after a while?

[h100vw]

I think I'd look for an electrical problem. Maybe the engine earth isn't quite right.

I had a mk1 and the VDOs used to read differently when you turned the lights on.

Try sticking a jump lead from the engine to the battery earth and see if things change.

Could also be the rectifier thing in the clocks playing up.

Gavin

[imported_brackie]

It's definitive. As long as your IR thermometer is reading OK (test in a kettle if you are uncertain) it's got to be the sender or the gauge. You can (sort of) test the sender with a multimeter. As the temp goes up the resistance goes down because the sender is leaking current to earth. I would first of all do what the Loon says and check earth between the battery and engine. Syncro is very good with VW electrics and it might be worth PM in him or leaving a mesage at his website.

[bitza]

I think you guys are onto it. It may be a earth issue as I checked the car again today after cleaening all the sender connector points. Funny thing is the car warmed up normally, then over heated on the gauge, then zeroed and bounced back up to just under the red. Then it continued to indicate overheat. (Infra red thermeter indicating every things OK). I then switched it off let it soak and then drove it again, it indicated overheating, I then drove it hard ie 5000 rpm plus, gauge fuctuated from hot to mid point and back, then settled down to a mid gauge point, I then drove it around hill and dale in the highest gear it could carry, ie trying to overheat it, nothing, the water temp gauge just stayed in mid position, oil temp on the dash computer indicating 90 to 92 degrees. Every thing normal, I'll look around tomorrow for an earth issue, and test the car again. Thanks. I'll let you know how I go.

As a side question is the oil temp measured on the trip computer screen a real measurement off a stand alone sender, or is it taken off the water temperature gauge? I measured sump temp and I get some 30 degrees cooler than that indicated on the screen. I wouldn't thing there was so much difference between in block measurement and the sump temp.

[imported_brackie]

There'll be a separate sender for oil temp. Look for it near the oil filter housing or on any external oil plumbing. Sorry, can't be of more help but I'm not familiar with the car. (Like to be... Like to have one in my shed!)

[h100vw]

Oil temp is off the top of the oil filter housing. A green and black wire if the colours are the same as VWs.

Oil should be at a lower temp than the water, unless you are really hammering it.

Gavin

[20v kit car]

sounds to me that the low water level switch is faulty...this is located in the resivour tank,sympton sounds similar..flashing light soon as you start? does this remain on?..may be worth a check..cheers steve

[bitza]

Hi Guys I thought I'd let you know the final solution.

It was an earth to the engine issue. Loosened the engine earth and retightened is, and the same on the battery to chassis earth, and the problem went away. The problem came back a week later, I checked the battery earth and pulled at it a little harder than usual it was loose. I cleaned that and retighted it and the problem has not returned. I am assuming that the resistance in both the water sender and oil temp gauge were affected, so why they were both reading off.

Anyway the problem has gone away. At last, after one water pump, three thermostates, and one water temp sender. How frustrating!!!!!!!!!!!!!