Cool Coolant - Gauge Seems To Read Low

[ed1948]

Once the engine is warmed up, the indicated temp never gets past this number. It's around 75 degrees Celcius. (170 F). Is this just gauge inaccuracy or does the engine run this 'cold'?
The heater output(in spring) seems normal.

 

[pagrunt]

Thermostat stuck open?

 

[ed1948]

I need to feel the rad hose next time I do a cold start.

 

[foxtrot]

Stock 305? If so, I wouldn't think that the coolant would heat up to 170 degrees if the thermostat was stuck open. My guess would be an inaccurate sensor, maybe you could check the engine temp with another method somehow?

 

[pontiacgp]

One of these can easily tell you what the temperature is on the thermostat housing, your reading will be about 10°F lower than the actual temperature of the coolant, and if you have headers it can tell you what cylinders are firing and which ones are not and can help you out seeing if your catalytic converter is operating properly.

 

[foxtrot]

One of these can easily tell you what the temperature is on the thermostat housing, your reading will be about 10°F lower than the actual temperature of the coolant, and if you have headers it can tell you what cylinders are firing and which ones are not and can help you out seeing if your catalytic converter is operating properly.

I always thought that those were 'exotic' and hence expensive. Just checked on Amazon and they had a good selection in the $15 (US) price range. I'll have to order one of those the next time I order from Amazon..

 

[pontiacgp]

I always thought that those were 'exotic' and hence expensive. Just checked on Amazon and they had a good selection in the $15 (US) price range. I'll have to order one of those the next time I order from Amazon..

you might want to spend a bit more to get one with a laser sighting light so you know where you are targeting

 

[ed1948]

I think it's the thermostat. On a cold start, 3 minutes in, I can feel the top rad entry getting warm.
Correct me if I'm mistaken in this observation - in the past, during a warm up, the needle overshoots the 'normal temp' and when the thermos fully opens, the temp drops slightly.

 

[ed1948]

One of these can easily tell you what the temperature is on the thermostat housing, your reading will be about 10°F lower than the actual temperature of the coolant, and if you have headers it can tell you what cylinders are firing and which ones are not and can help you out seeing if your catalytic converter is operating properly.

You can also use this temp reader to point at your body and watch the temperature rise when the driving school car(usually a Corolla)tries to park close to your G body.

 

[ed1948]

Dumb question, maybe?
Is it ok to drive for a short while with the t stat opening too soon? Is there a chance of excessive carbon buildup fro the engine running cool?