h-u-t-c-h-i

So I've I owned my car for 5 years, looked after it lovingly and it's never given me any trouble. It's garaged over winter and I usually turn it over every week or so and let it run up to temp. Today I did the usual but was working on another car and let it run a bit longer than normal, about an hour or so. So when I go to turn it off I notice that the temp gauge is up at four bars (MY 02 so 3 is normal) - first time I've ever seen it do this. Without jumping to worst case scenarios, the car was in the garage so no airflow through the engine. The radiator was roasting but the fans were not kicking in (stood and watched in hope that they would).
Basically what I'm asking is - is there any way I can test the thermostat and fans are working properly without taking too much apart? And is there anything else I should check/be concerned about. I'll go back out after its cooled down and double check all my fluid levels but I'm confident they will be ok as I keep on top of them and there's no obvious signs of leakage on the floor.

Thanks in advance.

tozerman

You should be ok with 4 bars, unplug the fan switch and short the plug, if the fans kick in then the sender is at fault if they don't then maybe the fans are fooked, I think that would be rare though.

lovegroova

Yes, you should be concerned.

My recent Head gasket problems caused similar (though much worse). The car had never been over 3 bars in 11 years before that, including 35C track days.

If the coolant level is higher than it should be, that points to head gasket or thermostat problems. Lots of really great advice in my recent thread: https://www.s2ki.com/s2000/topic/113...lant-problems/

RichwiththeS2000

You said yourself, it's roasting but fans not kicking in. Sounds like they should be. I've had two S2ks and never saw them go over their 'normal' temp zone even under crazy driving and really hot traffic. Hope it's OK

flanders

In the future it's probably better to just let the car sit until spring, just disconnect the battery or use a trickle charger.

richmc

You can test the thermostat/water pump by starting the car from cold with the rad cap off. when it gets near to temperature you should see the water moving past the cap hole.

martin j

Or when running the radiator hose connecting the stat will get hot as it opens allowing water to flow around the system, did you check the heater was working, an air lock settled maybe?

h-u-t-c-h-i

Thanks for the replies. So I checked my fluids - all ok, heater working fine - really hot, coolant is coming back through the rad - level came up on the filler when lid was off and coolant was hot coming back to the rad so the only thing I can think of is the fans are not working. How long should it take for them to kick in when engine is up to temp? And is it as straight forward as taking a positive and negative from the battery and putting them on the fan connector to see if they will run?

Chuck S

Four (4) bars on an AP1 equates to 235°F - 246°F. Normal operating temperature of the coolant should remain right about 200°F so I'd personally be concerned.

Three (3) bars is a wide range of 160°F - 235°F making the gauge an idiot light of sorts. The fans should come on somewhere in this range -- I'm guessing somewhere over 200°F. Fan sensor in the radiator is the first suspect.

Shorting the connector will tell you if the fans are working. I believe there's a 20amp fuse and and a relay in the primary under-hood/bonnet fuse box.

(The AP2-type dashboard has many more bars on this gauge. 8 is normal. Jumps to 12 in the temperature range you're showing. Very noticeable.)

-- Chuck

Nick Graves

Fans usually cut in before four bars. Or at.

Short the thermoswitch connector first as instructed. If nothing happens, check fuses/bleedin' ovvious before more expensive dismantling.