Napboy

I only ask that you control your urge to tell me it's normal before you finish reading.

I've had the car for 7 years and during hot weather here in San Diego from time to time, the fan continues to run after I shut down the car. It didn't happen often, but usually in very warm weather. Well, it began happening again this summer and I didn't think much about it. However, now it happens EVERY time I shut down the car no matter the weather. This has been going of for a couple of months now. Even on my way to work in the morning when the temps are in the low 60's. Sometimes the fan stays on for 10 seconds and other times it stays on for minutes.
I had the radiator flushed to see if that kept temps down, but that didn't help.

So my question is could I have a faulty temp sensor, a bad fan relay, or is the engine really running hot even in cool weather? How can I tell if the engine is running hot. Is the temp guage a dummy gauge when it reaches a certain temp? I know, I know, it's normal.

Jon316G

iTrader: (1)

Temps here in Ohio have been in the low 60s at night and my fans don't stay on.
The two fans work off of 3 relays and I'm looking that over to see if its plausible for one relay sticking to cause this.
Do both fans run at high speed, medium speed, or does just one fan operate?
Knowing what the ECT is displaying might tell us if you have a bad sensor.
Can't see it being something like a seized thermostat or water pump...

A scan device such as the AccessPORT than can display live data from the ECT (engine coolant temp).

It a "dummy gauge" until the temps get really high (I forget what that is).

Napboy

I'll have to look closer to see how many of the fans are running. Today, the fans were running on high for at least 2 minutes. I would say when the temps are in the 70's, they are running at medium speed for a fairly short time. Then when they're on low, they don't stay on for too long.

I wish I had a scan device. Obviously, I'm not willing to invest in an AP for temp readings. I know there's a million other uses, but is there any other easier way?

As for the dummy gauge, does it reach normal operating temps, then become "stupid" or is it higher than that?

Jon316G

iTrader: (1)

If you're noticing the fans are operating at various speeds, then I would rule out stuck relay because the fan speeds are based on which relays are energized.

If you don't know anyone around you that could lend you their AccessPORT or similar device, there isn't much else.
If you have a Multimeter that can display temp (they usually come with a thermocouple), you can read the signal from the ECT sensor itself that way (I know... its not an "easier way").
I did this for fun when I installed my water temp adapter for my gauges.

When the car is warmed-up, the needle will be at almost the half-way point.
It'll stay here until the temp reaches a really high number (something like 240... probably wrong) and then you'll see the needle continue sweeping over.

And I'm not sure if the IAT (intake air temp) plays a factor for the fans remaining on.
I'll have to look-up what conditions are needed...

Jon316G

iTrader: (1)

Here are the conditions for each relay and fan:

Aipex8

iTrader: (1)

Same thing happened to my car. Kept telling myself I was just imagining it getting worse and that it was normal. Sooner or later I started noticing my temp gauge moving (I'm sure yours is sitting at the higher end of the normal range). Swapped my water pump and thermostat and now my fans hardly ever come on. I upgraded to Mazmart pump and thermo, but I'll bet even OEM parts would have solved the problem. BTW, my fans started running more than normal probably six months before it started getting hot enough for the gauge to move... a slow failure.

Jon316G

iTrader: (1)

^I can see that... the thermostat isn't opening completely and allowing the temps to get higher than normal since the coolant is recirculating through the engine.

Napboy

Thanks for all the info. I really appreciate it.

Jon, you're right about it not being a malfunction of the ECT. Assuming it's a temp issue, would it be smart to start with the thermostat first and then the water pump, vice versa, or should I do it all at once?

HomicidalApple

iTrader: (3)

Mazmart has great water pumps, you should look into it if thats the case

Napboy

Do you think it's worth the extra cost for the upgraded water pump and thermostat? It's just a daily driver for me. No autocrossing or track days. And I'm not in desert heat for 95% of the year.

Razz1

Yes, because the RX engine is 1.5 x hotter than a piston.