Temp not rising above 150

[Pjhanlo]

Hey guys.

1993 Chevy c1500 rwd
5.7l TBI

I’ve replaced the thermostat. The upper coolant tube is hot, so I believe it’s not faulty.

I’ve replaced the temp sensor ontop of the engine next to the thermostat housing.

The temp reading on the dashboard climbs to 150 and never rises from there. Today after getting off the highway and parking the car I noticed some smoking under the hood.

I don’t think I’d experience any smoking if the temp was 65 degrees under operating level.

Do you guys have any ideas?

 

[Pjhanlo]

I should also add the car seems the idle and drive fine. Didn’t notice any issues with performance or safety until the smoking

 

[DerekTheGreat]

Connect a scan tool and find out what the ECM is seeing. These use two different temperature sensors, one for the ECM (near the thermostat) and one for the gage (driver's side cylinder head). So it's not unusual for the two to differ somewhat. Also, what temperature thermostat did you put in?

 

[Das Hatt]

The temperature sensor next to the thermostat housing just goes to the ECU. It has nothing to do with the gauge on the dash. That signal comes from the temperature sender located on the driver side head between cylinders 1 and 3 near the spark plugs.

Was it smoke or steam? Could you tell where the 'smoke' was coming from? Do you have enough coolant? With the engine cool open the radiator cap to see if you have coolant sitting right near the top. If you don't, you're low on coolant.

 

[Caman96]

So, I also wouldn’t trust the temperature gauge saying 150° as being accurate.

 

[Pjhanlo]

Connect a scan tool and find out what the ECM is seeing. These use two different temperature sensors, one for the ECM (near the thermostat) and one for the gage (driver's side cylinder head). So it's not unusual for the two to differ somewhat. Also, what temperature thermostat did you put in?

I put a 195 thermostat in. I’ll replace the gage sensor and give it a test drive

 

[Pjhanlo]

The temperature sensor next to the thermostat housing just goes to the ECU. It has nothing to do with the gauge on the dash. That signal comes from the temperature sender located on the driver side head between cylinders 1 and 3 near the spark plugs.

Was it smoke or steam? Could you tell where the 'smoke' was coming from? Do you have enough coolant? With the engine cool open the radiator cap to see if you have coolant sitting right near the top. If you don't, you're low on coolant.

I could not tell where exactly unfortunately. It’s possible I spilled some fluid earlier in the day but I don’t see why it would be causing smoke 8 hours later.

Coolant is at appropriate level

 

[Caman96]

How much of a difference does your gauge read compared to this:

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[Pjhanlo]

How much of a difference does your gauge read compared to this:

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Almost identical

 

[L31MaxExpress]

How much of a difference does your gauge read compared to this:

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I concour with your dash readings being fairly normal. That is exactly where the van runs with the engine at about 200°F. The dash gauge will read 210F at very close to 210F coolant temp. 210F is where my clutch fan really ramps up to RPM.

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