| T O P I C R E V I E W |
| JimDrewett |
Posted - 28 Jul 2015 : 12:37:22
Don’t know if anyone has had similar problem or can offer advice on our 1968 Sunbeam Rapier Fastback. Temperature gauge was in the red all the way on a recent hour journey, however the engine didn’t feel hot and it hadn’t used any water. Same result on a very short journey next day.
First step, we bought a new sender unit – however, same problem.
Then bought new temperature gauge – same problem – ran 2 hours back from Gaydon on Saturday and gauge in red all the time I was accelerating and would only come down very slightly when idling or going downhill.
Thought it might be lazy / faulty thermostat – tested it in hot water and it had to get very hot before opening. Bought new thermostat and fitted yesterday. Same result! Within a minute of starting up – the needle on the gauge was a far as it could go.
Garage have said about flushing out the radiator, trying the heater blower etc – but it seems to me that if the engine is not getting hot and it isn’t using water, then it is the reading that is at fault not the cooling system. But having changed everything – we don’t know what else to do.
Any thoughts much appreciated!
James
|
| 11 L A T E S T R E P L I E S (Newest First) |
| JimDrewett |
Posted - 17 Aug 2015 : 10:25:02
Looks like we've found the problem. When I said that the fuel gauge was working and it was only the temperature gauge I was ruling out a problem with the voltage stabiliser. However, what I didn't realise until my friend pointed it out on Saturday was that although the fuel gauge was going up and down when I put in/used fuel - this happens anyway but does not mean the gauge is giving an accurate reading. When he tested it by rigging up with a 9v battery with the car running - the temperature gauge was running much more like it used to be (although lower due to the 9v battery). Also the fuel gauge was showing a much lower reading (practically empty instead of the quarter of tank we thought we had!). So it seemed we'd need a new voltage stabliser - however on the way home the temperature gauge was running half-way between normal and high - like it used to! It seems that in taking off and putting back the voltage stabliser a connection had been made. Bear in mind I'm not technically minded - but maybe it a was a simple solution after all - something learnt! Thanks for all your helpful advice - it lead us to fault eventually. Unfortunately now have a slight fuel leak on one of the carburetors - I'll set up a new post for that one... |
| JimDrewett |
Posted - 06 Aug 2015 : 08:41:32
Thanks for your advice. I think it must be to do with the wiring as a lot had to be sorted out at mot due to brakes sticking on, fuses blowing. A friend of mine who has more technical expertise is going to have a look at the wiring a week Saturday - he has a volt meter - so I'll show him your suggestions. Many thanks - hopefully I'll be posting a successful solution soon! |
| pruyter |
Posted - 03 Aug 2015 : 17:10:31
Hi James,
Did you try changing the wire from the temp gauge to the sender? If this wire is touching ground before the sender then you experience exactly what you have described.
Regards,
Peter |
| pruyter |
Posted - 31 Jul 2015 : 09:34:58
you have changed about everything like gauge,sender and thermostat. If the voltage stabilizer should be the culprit then you should have trouble too with the fuel gauge which you haven't. The only thing that you did not change is the wiring.
The gauge is feeded via a fuse and the volt stablizer while earth is connected from the gauge via the sender. The feed must work otherwise you should not have a reading at the gauge. That leaves you with the earth connection. What you could do is this: make a temporary new eart connection between the gauge and the sender. If that solves your problem you know what you have to do. If it doesn't then the situation is going to be difficult. In this case you could check very good if your fuel gauge isn't readig wrong or just change the volt stabilizer (they are very cheap) although it is against my better judgement. As a last thing (for being 100% sure about the temp of the engine) you could measure the temperature of the cooling liquid with a infra red temp tester.
Regards,
Peter |
| arrocuda |
Posted - 31 Jul 2015 : 09:18:58
Have you checked out the thermocouple (sender device)? You can test it by measuring the resistance with an ohmmeter. If the reading is same when the engine is hot as it is at ambient temperature, you know it's had it. They're not expensive so you could maybe swap it out anyway.
Tim
Building the 'Mark II' fastback Rapier ('Arrocuda'). |
| JimDrewett |
Posted - 30 Jul 2015 : 20:26:03
Ah that's interesting - absolutely no probs with fuel gauge - so does that mean it's back to the drawing board? |
| pruyter |
Posted - 30 Jul 2015 : 09:15:28
Both the temp gauge and the fuel gauge are connected to it. So if this voltstabilisator is the culprit then most likely there is something wrong with the fuel gauge also.
Regards,
Peter |
| JimDrewett |
Posted - 30 Jul 2015 : 09:06:07
Thanks that's very helpful. May have to trust this to the garage though as dad blew the fuse when he put the temperature gauge in! He's more used to working on trucks... |
| arrocuda |
Posted - 30 Jul 2015 : 07:53:06
IIRC it's mounted on or near the steering column under the dash. It only has two connecting points on it so shouldn't be too difficult. Just remember to note the wire colours and terminals before removing it.
Tim
Building the 'Mark II' fastback Rapier ('Arrocuda'). |
| JimDrewett |
Posted - 28 Jul 2015 : 21:44:22
Thanks - something else to follow up - now to track one down and work out how to install one! |
| pruyter |
Posted - 28 Jul 2015 : 14:33:47
A possible cause is the voltage stabilisizer, but then one would expect some wrong reading with the fuel gauge also.
Regards,
Peter |
