Car Not Getting To Operating Temp

[Luang]

My skyline over the past week has not been getting to operating temp. on wed it was just below half of the temp gauge the next day it went to 1/4 of it and now it barley makes it past half the cold line and goes below at hwy speeds.

So i was wondering what the problem might be? Could it be the thermostat just staying stuck open or something else. I can get a thermostat for the rb20 at sunridge Nissan because they have one in stock right now. Thanks for the help in advanced.

[Lucky97]

sounds like you may need a new thermostat and a rad flush

[Go4Long]

A thermostat being stuck open would still eventually let your car get up to temperature, and once it got there it would almost certainly eventually over heat. Normally a thermostat would hold some fluid in the rad to be cooled, but when it's stuck open all the coolant is just circulating all the time, so it will never cool properly.

I would lean more towards a faulty temperature sensor.

[sr20s14zenki]

Easy way to find out. Get on the hiway, and when the gauge is reading cold, do you get heat? If you do, faulty sensor, if you dont, its your thermostat OR failing water pump, but the waterpump would cause overheating.

[YamahaV8]

Originally posted by Go4Long
A thermostat being stuck open would still eventually let your car get up to temperature, and once it got there it would almost certainly eventually over heat. Normally a thermostat would hold some fluid in the rad to be cooled, but when it's stuck open all the coolant is just circulating all the time, so it will never cool properly.

What? That doesn't make any sense at all.

OP do what sr20s14zenki said to do. In this cool wet weather a stuck open thermostat will most definitely keep your car from heating up. Change your thermostat and get a coolant flush done. Cheap cheap if you can do it yourself.

[J-hop]

Originally posted by Go4Long
A thermostat being stuck open would still eventually let your car get up to temperature, and once it got there it would almost certainly eventually over heat. Normally a thermostat would hold some fluid in the rad to be cooled, but when it's stuck open all the coolant is just circulating all the time, so it will never cool properly.

I would lean more towards a faulty temperature sensor.

?, the thermostat's function is to regulate the temperature of the coolant. The thermostat on a car has a set temperature to open at (on the common thermostat I believe it has to do with wax inside melting at the set temp). Prior to this temperature the thermostat stays closed, not allowing flow through the radiator causing the engine to heat up as the heat has no where else to go. When the specific temperature is reached the thermostat pops open allowing the coolant to flow through the radiator which transfers heat away from the coolant (which I'm sure you understand). If the temperature of the coolant ever drops below the set temperature for the thermostat to open then it closes again. This opening and closing of the thermostat along with the fan and radiator are what regulate the coolant temp and subsequently engine temp (for the most part).

Therefore if the thermostat is stuck open- the engine may never be able to achieve operating temperature unless under high load in hot conditions because there is a constant flow of coolant to the radiator and the radiator is constantly dissipating heat away from the coolant.

To answer the OP's question I think Yamaha and sr20 (and the OP's initial guess) are right, it is likely stuck open. What makes me think this is that it is barely going up and then when you hit the highway it drops down, this is likely due to the fact that when you are at highway speeds there is a ton of flow to the radiator and a lot of heat is dissipated away from the coolant resulting in the engine having even more trouble building up any heat.

[crapstixs]

start up the engine cold, hold at 2000rpm. the upper rad hose will get hot first. when the t-stat opens the lower rad hose will get hot. if the t-stat is stuck open both upper and lower hoses will get warm at the same time.

[Go4Long]

[Luang]

Originally posted by J-hop


?, the thermostat's function is to regulate the temperature of the coolant. The thermostat on a car has a set temperature to open at (on the common thermostat I believe it has to do with wax inside melting at the set temp). Prior to this temperature the thermostat stays closed, not allowing flow through the radiator causing the engine to heat up as the heat has no where else to go. When the specific temperature is reached the thermostat pops open allowing the coolant to flow through the radiator which transfers heat away from the coolant (which I'm sure you understand). If the temperature of the coolant ever drops below the set temperature for the thermostat to open then it closes again. This opening and closing of the thermostat along with the fan and radiator are what regulate the coolant temp and subsequently engine temp (for the most part).

Therefore if the thermostat is stuck open- the engine may never be able to achieve operating temperature unless under high load in hot conditions because there is a constant flow of coolant to the radiator and the radiator is constantly dissipating heat away from the coolant.

To answer the OP's question I think Yamaha and sr20 (and the OP's initial guess) are right, it is likely stuck open. What makes me think this is that it is barely going up and then when you hit the highway it drops down, this is likely due to the fact that when you are at highway speeds there is a ton of flow to the radiator and a lot of heat is dissipated away from the coolant resulting in the engine having even more trouble building up any heat.

The top hose gets hot and the bottom stays cold :-S

[Kloubek]

I agree - this sounds like a thermostat issue.