SR20DET WON’T warm up

[nisileighty]

Hi all,

The car is a 93 coupe with a red top, second SR I’ve had. OEM clutch fan setup with a aluminum ISR radiator. Same exact setup I’ve had on my first SR before I swapped it for an RB.

Now that the car has been tuned with a power fc, it literally will not heat up on either the cluster temp gauge (unreliable) and the power fc commander (reliable). When I sit and let it idle for about an hour, the water temp will rise to about 65 degrees Celsius on the PFCC, and the oil will get to about 100 degrees Fahrenheit on the AEM temp gauge tapped into the oil pan.

Since it is a PFC with fuel correction, it won’t run correctly unless it’s at operating temp (78 Celsius) which gives me big problems trying to drive it, being boggy, hesitating, etc. Obviously I don’t have and hour and a half to sit and let it warm up every day, which has forced me to literally not drive the car anymore. I’ve replaced the thermostat TWICE with no change.

Any clarifying questions feel free to ask, but I’m very intrigued by this problem and looking for some help from anyone. TIA!

[e1_griego]

You're sure the temp sender is working correctly?

Can't imagine two thermostats would have the same result.

Also, I assume you're using oem-ish thermostats (~175*F)?

[nisileighty]

You're sure the temp sender is working correctly?

Can't imagine two thermostats would have the same result.

Also, I assume you're using oem-ish thermostats (~175*F)?



Yes and yes.

I should’ve noted I’ve replaced both temp sensors as well with the same results. OEM spec thermo as well.

[relaxamigo]

In order to isolate if the problem is mechanical or a electronic, I recommend installing a temp gauge on ur upper rad hose. I'm not an expert on the power-FC but I assume it gets its reading from ur temp sensor/sender?

If the external water temp gauge does indeed read cold I'd say it's safe to assume the issue is mechanical. I understand you replaced the sensor but there could be a gremlin in the wiring somewhere, and the external gauge would narrow down your problem a bit.

[nisileighty]

In order to isolate if the problem is mechanical or a electronic, I recommend installing a temp gauge on ur upper rad hose. I'm not an expert on the power-FC but I assume it gets its reading from ur temp sensor/sender?

If the external water temp gauge does indeed read cold I'd say it's safe to assume the issue is mechanical. I understand you replaced the sensor but there could be a gremlin in the wiring somewhere, and the external gauge would narrow down your problem a bit.



That’s a good idea, something I may do soon as well. However, the oil temp is still left unexplained, and they generally heat up hand in hand.

[mr.nismo.]

That’s a good idea, something I may do soon as well. However, the oil temp is still left unexplained, and they generally heat up hand in hand.I'd this the coupe that got totalled? :-/

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[nisileighty]

I'd this the coupe that got totalled? :-/

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Nope, thankfully. The one that got totaled would’ve been a 3rd in my possession, but 11th overall.

[mr.nismo.]

Glad to hear. Now with your issue on your temp, I agree with putting a sensor in the upper hose (real time temp off the head). I've had my SR for about 6 years without fail. Also how cold is it where you are? I've found that when I lived in Kentucky with winter, the car would never fully warm, even with a 30 min drive. You could have a wiring issue, but it could be for to too much fluid to get to operating temp with you ambient temperature (massive rad is super cooling what's in it and once the tstas opens, it gets rushed with cold water). Had the same deal with my greddy oil pan (about 7 qts total w/ cooler). It would take forever to get to operating temps. Switched to p2m pan (just under 6 qts), and the oil gets to temp no problem w/ the oil cooler regulating it.

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[nisileighty]

Glad to hear. Now with your issue on your temp, I agree with putting a sensor in the upper hose (real time temp off the head). I've had my SR for about 6 years without fail. Also how cold is it where you are? I've found that when I lived in Kentucky with winter, the car would never fully warm, even with a 30 min drive. You could have a wiring issue, but it could be for to too much fluid to get to operating temp with you ambient temperature (massive rad is super cooling what's in it and once the tstas opens, it gets rushed with cold water). Had the same deal with my greddy oil pan (about 7 qts total w/ cooler). It would take forever to get to operating temps. Switched to p2m pan (just under 6 qts), and the oil gets to temp no problem w/ the oil cooler regulating it.

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Yeah, probably is a good idea to put a temp gauge from the water neck.

I live in Seattle, the past week has been high 20’s low 30’s, but the average temp is 50ish.

Oil temps are also super cold, is the oil pan an inaccurate place to get a reading from? I have an ARC pan.

[Kingtal0n]

it must be sucking cold water from somewhere

[mr.nismo.]

At the end of the day, it's a 2l 4 cyl. They get super hot with abuse in warm weather, so we throw huge radiators and oil pans for more fluid to fight heat soak. However, with normal driving it doesn't need all of that. Even more so with cold temps. So it takes forever to bring all that fluid up to operating temp. As for oil pan temp sensor, generally yes, it's the best spot. Mainly because it's the average temp of everything in the motor. Oil temps will be all over the place depending on where you look (temp of oil coming from the turbo will be way hotter than say the oil coming out of a cam squirter). But an even more important reason to get it from the pan is because that's where oil will be getting pulled from, and back on whatever path to whatever part it ends up lubricating. That way, you have an overall view of what's happening. Your arc pan is like the greddy pan in the sense it holds a LOT of oil. Even here in Cali, I noticed that it would take a long time to bring oil temps up unless I was beating the hell out of it. That's why I switched to a p2m pan and I have an HKS cooler (thermostatic w/ cooling fan, 200/190 temp switch). No more issues bringing fluids up to temp.

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[LoSt180]

What thermostat do you have? Sounds like it's stuck open, or you have something like a Nismo that opens at a low temp.

When the ambient temp is really low, it'll be nearly impossible to raise the temp above the thermostat opening point. 65C is roughly 140F, which is what I see some of these low temp thermostats advertised. If that's what you have, put a stock 180F thermostat in there.

Normal operating temp range should be 180-210F. Not a cool 140F.