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Start my car today, help over coolant ratio


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Daft question, I know!

I'm starting my car today, and so adding coolant.  Caterham sent Millers Alpine Antifreeze Extend Red OAT Technology Antifreeze and coolant Concentrate.

The label on the back of the bottle say to dilute, and it is concentrate,  but it doesn't say what ratio.

I can't find any specs in the assembly guide or owners handbook.

Question is do I dilute?  If so to what ratio?

Sorry dumb question I know, but I just want to get it right,

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Alpine Antifreeze Extend is an ethylene glycol based automotive antifreeze and coolant, suitable for all year round use in the cooling systems of all internal combustion engines. Utilising OAT (Organic Acid Technology).


To be used diluted with water for engine cooling systems in cars, vans, trucks, plant, buses and coaches with corrosion and frost protection. From 33% volume in water providing pumpability down to -12°C, to 50% volume in water providing pumpability down to -40°C.

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It takes an age for the fan to kick in with your ally radiator. Is the Thermostat opening up as it may need quite a time at idle to actuate the thermo on a day like today.  You'll need to be about 95 degrees plus on your temp gauge from memory before the fan kicks in.  Are you bleeding from the top of the rad, and is the lower rad pipe as warm as the top?

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I think you can be relaxed about leaving the gauge needle to cover / go beyond to the last but one marker line which would be 110.  See if the fan kicks in then.  Remember that the fan is pretty quiet so a visual look see is worth doing.  I'd also let things run to the marker on the gauge as it sounds like possibly the thermostat is not fully opening, but this does not imply it is at fault..  Without the thermo open bleeding will be difficult.

There are also a couple of redundant loom leads from memory  that can be misinterpreted as the fan feed, but I'd persevere with the above if it was me. Next step would be a continuity check on the fan circuit, but hopefully this will not be necessary.


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I'd suspect that things will start to happen before you get to 110. One problem with the Seven gauges is possibly a combination of parts newness, accuracy, linearity, and lack of any markers between 80 and 110.  In summer and in traffic you will see 110 on the gauge. If it's any help, i was bricking myself for the same reasons on my first engine run up.

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I don't think you're running the engine long enough to get the fan working. On my Duratec the fan doesn't kick in until about 105° and then off about 103°. The engine will run about 95°-100° in normal conditions, but will climb when air flow stops, ie in traffic.

Different engines have different numbers eg my old Sigma fan kicked in about 95°. 

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#18 is the answer that Derek will give you if you call him on Monday.

If the nose cone is off the car, I'd put it on to assist heat retention around the rad and to make sure that the thermostat has fully opened.  Keep an eye on the temp gauge and if the fan does not come on by 110 then there might be a basis to check the fan wiring.  The ECU that controls the fan is not likely to be defective.  You can pop a 12V supply through the fan motor by disconnecting its plugs into the loom to settle yourself down on that score.

Mark just to mention that, with a Seven in an garage and the engine running, you need to watch the fan as you will not hear it running.  It also can tickle on for very short intervals before going off again.

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Thanks everyone for your help today.

Overall I'm fairly happy with the progress, although I do have some remaining gremlins/issues.

In terms of the initial start, we cranked the car over with the plugs out for 3 sets of 5secs and it developed oil pressure quickly, 4 bar/psi whichever it is.  Plugs were then put back in along with the inertia switch.  We then cranked over for the start, it took longer than I thought and started to kill the battery but we did get there and it ran sweet.  Sounds very nice.

We ran the car conservatively with temperature to start with, following the original 2015 assembly guidelines which state 94c for the max etc.  Eventually, through support from the forum, we went higher and managed to get all the coolant pipes and the entire radiator hot.  We also had to squish the bottom hose a fair bit, I think to help air along the way.

Unfortunately, we've been unable to get the fan running.  I've used my OBDII reader, and it reports the coolant temp along with many other data values.  I could see the coolant rise to 106, still no fan.  I didn't go any higher.  Given prior feedback that the ECU switches the fan I'm assuming 106 should be sufficient for the ECU to turn it on.

We also shorted the temp sender, which raised the temp reading, but still didn't start the fan.

I also noticed a number of other potential electric gremlins during the day.
No brake lights and no reverse light.
One rear main light seems brighter than the other.
The pre-fitted led number plate light doesn't work either

Is it possible I've some general electrical issue which is affecting the fan and the above?

Everything else seems fine.

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I find the gauges are a guide and not accurate enough to base any diagnostics on, after all the sensor and it’s earth are in the submarine tube, not on the engine.  The ECU temperature is the only real guide but you can’t get to that without easymap.  My car reads about 10C above the ECU on the gauge.

I also think there is probably nothing wrong, but that will depend on the thermostat fitted to your car? Any chance you could post a picture of it.  If you look at the CC parts website you will see two Duratec thermostats the 82C or 105C, the 105C has much longer plastic hoses on the housing.  The 105C stat is what expect to be fitted to your car, it was mine.  Since mine was an early 360R the ECU was programed to switch the fan on at 95C and off at 93C, which meant the fan was running pointlessly because  the stat had not opened and the bottom hose was cold.   If you haven’t got that situation then I suspect you have no problem.

If you are confident you have no got an air lock, wait for the bottom hose to get hot, I.e. the stat to open, then wait a bit more for the fan to come on.   If your not confident on the air locks, get hold of a IR thermometer, test it on some boiling water in a pan, then let it run up to temperature checking with the IR thermometer.

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We've tested the fan with a 12v supply from a bench power supply and it ran fine, so I'm happy the fan itself is not faulty.  Not sure on the relay etc.

I had the support of a friend all day, and we watched the fan like a hawk so I'm pretty confident we didn't miss it. 

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