Testing the water temperature gauge?
Discussion
Hi all.
Just started work on the Cerbera, the head gaskets are going to be replaced etc. During the time running up to the failure, the water temp gauge was reading rather erratically, namely jumping around the gauge in 20 degree bursts and generally not having a clue what was going on. I expect this was down to the head gaskets, but there is the chance that the gauge is faulty too. What I don't to do is send it to Speedy Cables, find out there was nothing wrong and have to pay postage/labour time etc unnecessarily. Is there a way of testing the gauge out of the car?
Cheers.
Just started work on the Cerbera, the head gaskets are going to be replaced etc. During the time running up to the failure, the water temp gauge was reading rather erratically, namely jumping around the gauge in 20 degree bursts and generally not having a clue what was going on. I expect this was down to the head gaskets, but there is the chance that the gauge is faulty too. What I don't to do is send it to Speedy Cables, find out there was nothing wrong and have to pay postage/labour time etc unnecessarily. Is there a way of testing the gauge out of the car?
Cheers.
Unscrew the bulb from the front water rail (carefully!!!) and stick it in a jug of hot water. Compare the gauge reading with the water temperature with a thermometer.
If you are unscrewing the bulb from the rail give it a really good soak in penetrating oil overnight before attempting to undo it and make sure that the nut is turning not the bulb so that the capillary doesn't get twisted. If you knacker the capillary then its off to Speedy (by name but not by nature) Cables with it.
If you are unscrewing the bulb from the rail give it a really good soak in penetrating oil overnight before attempting to undo it and make sure that the nut is turning not the bulb so that the capillary doesn't get twisted. If you knacker the capillary then its off to Speedy (by name but not by nature) Cables with it.
My temp gauge was very unreliable when I bought my car, until I broke it during a top end rebuild. The gauge then became even more useless during several professional repair attempts, until eventually it seemed to work ok.
Then two months ago after a great track day at Anglesey it starte playing up on the way home, jumping about just as you describe. I became quite despondent over the prospect of trying to get it repaired again.
After an hour of driving with the gauge going bonkers the car started pinking - Oh No!
It wasn't misbehaving, the car was overheating badly. I was only ten minutes away from my destination when I pulled up and stopped, after letting the car cool down I tip toed back for the last ten minutes. After a couple of glasses of vino, I filled the cooling system with nearly ten litres of water.
The expansion tank does have a coolant level sensor, but in their wisdom TVR decided to leave it unused. My rad had sprang a leak, and on the four hour drive back from the track, most coolant had been lost, and that I thought was probably the end of my AJP8.
After replacing the rad and doing track days at Zolder and the Ring, I can be pretty certain no permanent damage was caused, but I reckon it was a very close call.
On the trip to the Ring the hand brake warning light started misbehaving again, I knew it was just the little aluminium tab slipping so the micro switch wasn't being activated, so I ignored it (I can't really see the warning lamp because it's obscured by the steering wheel just like the indicators). Of course what had actually happened was the brake fluid level had gone low as the pads wore during fun on track - Doh!
I think the moral is - Assume the Worst!
Then two months ago after a great track day at Anglesey it starte playing up on the way home, jumping about just as you describe. I became quite despondent over the prospect of trying to get it repaired again.
After an hour of driving with the gauge going bonkers the car started pinking - Oh No!
It wasn't misbehaving, the car was overheating badly. I was only ten minutes away from my destination when I pulled up and stopped, after letting the car cool down I tip toed back for the last ten minutes. After a couple of glasses of vino, I filled the cooling system with nearly ten litres of water.
The expansion tank does have a coolant level sensor, but in their wisdom TVR decided to leave it unused. My rad had sprang a leak, and on the four hour drive back from the track, most coolant had been lost, and that I thought was probably the end of my AJP8.
After replacing the rad and doing track days at Zolder and the Ring, I can be pretty certain no permanent damage was caused, but I reckon it was a very close call.
On the trip to the Ring the hand brake warning light started misbehaving again, I knew it was just the little aluminium tab slipping so the micro switch wasn't being activated, so I ignored it (I can't really see the warning lamp because it's obscured by the steering wheel just like the indicators). Of course what had actually happened was the brake fluid level had gone low as the pads wore during fun on track - Doh!
I think the moral is - Assume the Worst!
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