- My model of MX-5 is: Eunos 1.8 1996 V-Spec
- I’m based near: Edinburgh
- I’m looking for technical help or recommendations on: Fans and Oil temps
Hi Guys,
I have just completed the following work on my car over the weekend and had a worry that hopefully can be quashed.
- Timing belt change
- Water pump
- All cooling and breather hoses
- Skidnation coolant reroute
- Koyo performance radiator (53mm)
After starting the car last night and making sure the timing belt was good I tried to bleed the coolant. The procedure was to jack up the front of the car, fill the rad with distilled water and ‘burp’ the system by squeezing all of the hoses whilst the car was running and the heater blower was on. Eventually I got hot air coming out of the vents and after topping up the rad levels, everything seemed fine.
However I did not see the cooling fan turn on which was concerning. I don’t know the oil temperature since these cars don’t come with one so I can’t check to see if I am at the stage of potential damage. I took the car out for a quick 10 minute spirited drive around the city and idled it for a further 5 mins when I got back and still no fans turned on. I then turned the car off and jumped the cooling fan relay and the fan did turn of (RHS looking at the engine bay). So it definitely works. My questions are:
-
I forgot to buy a new cooling sensor when I fitted the skidnation kit (located at back of engine block). Could this be the issue?
-
Is the thermal capacity of my new radiator (53mm core) so much greater than my old crusty radiator that the oil wouldn’t be up to temp yet for the fans to turn on even after a small drive in the city?
Let me know what you guys think. Cheers!
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Given your big new rad, maybe the fan sensor is working correctly.
-
Is the thermostat near the water pump working correctly?
Have you measured the actual water temperature with an external thermometer?
I measured the temp sensor with a thermometer (same type as you linked). I put a bit of masking tape on the rad and measured it was 84 deg.
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Hmm that might be a bit low. But those optical things can read low.
I thought the rad should be working with full flow at about 88C, as the main-stat is meant to begin opening between 86.5 and 89.5, with the smaller sub-stat at 83.5-86.5
I’ve had a look and it seems the fan should start when the water reaches 97C, as decided by the “thermoswitch” on top of the thermostat housing at the start of the top hose.
So I have relocated my temp gauge to the back of the engine as per the reroute kit with skidnation. But I am no where near the 97 deg water temps to start the fans.
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Sorry, I forgot to check the year of your NA.
The fan relay is switched by the ECU. So it depends on the linear sensor reading correctly. Position matters for full flow to be seen.
Only the earlier ones used the thermo-switch sitting on the stat housing for the fan, independently of the linear gauge sensor.
Cool. So you think think its alright then? I am taking to the track on the 15th and wanted to make sure its running alright before then.
I would take it for a longer drive nearer home first, give it time to settle, and recheck the water levels again.
Also simply letting it tick over for quarter of an hour will probably be long enough for it to cook up enough to switch on the fan - if it is going to at all.
Then yes! Have fun.
Turn your heater fan off. You’re shedding heat from the engine into the cabin. This will help the engine come up to temp quicker.
Ok I’ll follow your advice and see what happens.
Ah right. I left it on since I was bleeding the system and used the hot air as a guide that it was getting bled correctly and that the thermostat was operating.
Another thing. I refitted the CAS just as it went on. Do owners on here check their own timing with a light or just trust its done right if the car isn’t feeling sluggish?