290S Water Temp
Discussion
Only recently got the car so please be gentle. I'm after some advice on what would be perceived as a normal water temperature on a steady 60mph run. My car tends to temperature cycle which to my mind does not seem correct. The temperature will build upto the line on the dial above the 90 not sure if this relates to 90 or higher. The fans then kick in and the temp drops back down nicely, this cycle constantly repeats itself over a 5-6 minute period
I was expecting that the car could maintain a steady temperature without the need for fans at a constant 60mph. How does everyone elses car perform.
The cooling system is only a few years old, new rad, pipes, pressure cap on the swirl pot. I have also bled the system to death.
I was wondering if maybe the fan is coming on to early and if it waited a bit longer it might reach a steady temperature. I'm also concerned that if the fan is required to maintain temperature that if it fails disaster will strike.
Yours confused, Dan
I was expecting that the car could maintain a steady temperature without the need for fans at a constant 60mph. How does everyone elses car perform.
The cooling system is only a few years old, new rad, pipes, pressure cap on the swirl pot. I have also bled the system to death.
I was wondering if maybe the fan is coming on to early and if it waited a bit longer it might reach a steady temperature. I'm also concerned that if the fan is required to maintain temperature that if it fails disaster will strike.
Yours confused, Dan
Could depend on the temperature setting of both the engine thermostat and the fan activation thermostat. Sounds like the fan switch has a lower setting than the engine thermostat.
For example
If the engine has an 88degC stat and the fans have an 82degC stat then I would expect the cycling as you have.
Other symptoms may be available
For example
If the engine has an 88degC stat and the fans have an 82degC stat then I would expect the cycling as you have.
Other symptoms may be available
Hi, I thought your S was the yellow S1 recently advertised on ebay if so, I believe you have the 280S?
Temperature fluctuations seem to be 'normal' on these cars but might be worth changing the fan activation switch (AKA Otter switch) which is screwed into the radiator and is a simple coolant temperature on/off sensor and nothing to do with the ECU.
Peter
Temperature fluctuations seem to be 'normal' on these cars but might be worth changing the fan activation switch (AKA Otter switch) which is screwed into the radiator and is a simple coolant temperature on/off sensor and nothing to do with the ECU.
Peter
Edited by yknot on Friday 19th May 11:01
I'll have a bit more of a poke around and see what I can find. The cars not overheating I was just expecting that on a constant steady run the airflow through the radiator would be enough to maintain temperature.
Could it be that actually the fans not coming on at all and that the thermostat is opening and closing causing the temp fluctuations?
The car is actually an S1.5. I have the 2.9 V6 and a mix and match of S1 and S2 parts. Good old TVR not wanting to waste a single part..
Could it be that actually the fans not coming on at all and that the thermostat is opening and closing causing the temp fluctuations?
The car is actually an S1.5. I have the 2.9 V6 and a mix and match of S1 and S2 parts. Good old TVR not wanting to waste a single part..
Daniel-vwbsa said:
The fans then kick in and the temp drops back down nicely, this cycle constantly repeats itself over a 5-6 minute period
The radiator should be getting enough air flow to maintain temperature without fans at that speed.Do you know the fans actually kick in? It would be hard to detect at that speed. Fans will make a slight difference to cooling even at that speed so it's possible they are just making enough difference to pull the temperature down a little as you describe. An otter switch would typically have about a 5C hysteresis - is that the sort of temperature swing you're seeing?
If you haven't already, check the temperature difference between the top and bottom of the rad. They should be similar, but might differ if you have air in the rad.
GreenV8S said:
The radiator should be getting enough air flow to maintain temperature without fans at that speed.
Agree, If the car is moving steadily and all is well, then the fan shouldn't need to engage at all. Sitting in traffic for a few minutes should cause it to kick in and it will then cycle as described above.
Purging airlocks can be difficult, make sure the heater is on and then run a while with the swirl pot cap off. then refit, allow thermostat to open and drain any air from the top of the radiator, should be a tap.
Apologies if I misunderstood but how can you hear the fan coming on/off at 60mph? I'm sure I couldn't hear mine over the noise of the exhaust, etc!! 
Have you tested it when idling and stationary to be sure the fan is coming on at the temp you have reported? It could just be the normal fluctuation in engine temperature as the thermostat (88*C?) opens and closes which, on modern cars, you don't notice as their temp gauges are regulated.
As reported above, these cars have a TVR designed plumbing system which, by all accounts, are not good at getting the engine up to operating temperature although, if yours is reaching 90 degrees at speed at the current ambient temperatures, you maybe have the modification posted here;
https://www.pistonheads.com/gassing/topic.asp?h=0&...
Have you tested it when idling and stationary to be sure the fan is coming on at the temp you have reported? It could just be the normal fluctuation in engine temperature as the thermostat (88*C?) opens and closes which, on modern cars, you don't notice as their temp gauges are regulated.
As reported above, these cars have a TVR designed plumbing system which, by all accounts, are not good at getting the engine up to operating temperature although, if yours is reaching 90 degrees at speed at the current ambient temperatures, you maybe have the modification posted here;
https://www.pistonheads.com/gassing/topic.asp?h=0&...
Edited by yknot on Friday 19th May 15:00
magpies said:
I've also wired in one of the 'many' unused indicator warning lamps on my S1 dashboard to the outgoing terminal on the Rad Fan relay - so I now know when the rad fans are actuates.
this is a good idea, I also have done this using an override switch, so when you know you are going into traffic etc, you can manually get the fan on early. Best if the indicator is on the output of the relay as Mick suggests, then you can see the fan's normal triggering from the otter switch as well.yknot said:
Apologies if I misunderstood but how can you hear the fan coming on/off at 60mph? I'm sure I couldn't hear mine over the noise of the exhaust, etc!!
You are right I cannot confirm the fan is coming on that is just an assumption I'm making. I will look into getting a lamp installed to check this. I'm quite probably worrying about nothing. When stationary the fan tends to come on at around the 90 line and this is about what the temp gets to on the road before coming back down again hence the assumption.
It does seem that the thermostat opening temperature and fan turn on temperature are rather close together, I would have thought there would be a bigger deadband between them to allow the thermostat to do its job without the fan potentially interfering straight away
Thanks for all your advice it gives me a few thing to look at and try.
Edited by Daniel-vwbsa on Friday 19th May 16:17
yknot said:
Apologies if I misunderstood but how can you hear the fan coming on/off at 60mph? I'm sure I couldn't hear mine over the noise of the exhaust, etc!!
You are right I cannot confirm the fan is coming on that is just an assumption I'm making. I will look into getting a lamp installed to check this. I'm quite probably worrying about nothing. When stationary the fan tends to come on at around the 90 line and this is about what the temp gets to on the road before coming back down again hence the assumption.
It does seem that the thermostat opening temperature and fan turn on temperature are rather close together, I would have thought there would be a bigger deadband between them to allow the thermostat to do its job without the fan potentially interfering straight away
Thanks for all your advice it gives me a few thing to look at and try.
Edited by Daniel-vwbsa on Friday 19th May 16:51
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