Aftermarket Temp Gauge Question
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Teching In
Joined: Apr 2010
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Aftermarket Temp Gauge Question I have a stock LS 3 transplanted from a 2012 Camaro into an 83 Olds Delta 88. The real work was done by someone else, but I am slowly fixing small things. We are using an aftermarket water temp gauge with the sensor into the rear of the right cylinder head with an adapter from 12mm to 1/4npt. When left to idle, the gauge responds as expected with an indicated 200°, but when driven, the indicated temperature drops to about 165° and stays there until the engine is slowed to an idle for maybe 5 to 10 minutes. The scanned temperature that the ECM indicates, stays between 195° and 207° as it should and that sensor is in the front of the left cylinder head. The water pump is stock as is the thermostat. This engine only has the steam tube connections in the front of the engine and they are connected to a Tee fitting in the upper radiator hose which goes to the top of the radiator. Do I have an steam pocket problem or should that aftermarket sensor be moved from the rear of the right cylinder head to the water pump or elsewhere? Or what is the problem?
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Joined: Oct 2016
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From: PDX-OR-USA
The "regular" water temp on my L33 is on the front of the driver side head, same as the one your using on the passenger rear.
Both heads have the same hole in them. But somewhere (I cant find the reference now) I remember reading the driver front port
works better due to proximity to the water pump and the steam port in the head. LOL getting old..
Both heads have the same hole in them. But somewhere (I cant find the reference now) I remember reading the driver front port
works better due to proximity to the water pump and the steam port in the head. LOL getting old..
Water flow through the engine --- cooled coolant enters the block at the front, moves to the rear, enters the heads and moves from the back of the heads to the front where it leaves the engine for the radiator. General rule of thumb - you don't want a temp sensor at the back of the head as the temps there will generally/almost always be LOWER than the temp you'd like to monitor. The highest temps will be at the front of the head where coolant is leaving the block and heading to the rad for some thermal monkey-business. That's because the coolant picks up more heat as it moves through the heads.
I have a two coolant gauges on mine - one in the dash and one under the hood. I mounted both sensors in the side tank of the radiator just below where the upper hose (hot coolant leaving the engine) connects. They read within a few degrees of the temp the ECU sensor (U.S. driver's front head) spits out on my hand held.
If it were mine, I'd want that gauge sender relocated. My motor very similar to yours -- crate LS3 circa 2015.
I have a two coolant gauges on mine - one in the dash and one under the hood. I mounted both sensors in the side tank of the radiator just below where the upper hose (hot coolant leaving the engine) connects. They read within a few degrees of the temp the ECU sensor (U.S. driver's front head) spits out on my hand held.
If it were mine, I'd want that gauge sender relocated. My motor very similar to yours -- crate LS3 circa 2015.
Thread Starter
Teching In
Joined: Apr 2010
Posts: 48
Likes: 1
Water flow through the engine --- cooled coolant enters the block at the front, moves to the rear, enters the heads and moves from the back of the heads to the front where it leaves the engine for the radiator. General rule of thumb - you don't want a temp sensor at the back of the head as the temps there will generally/almost always be LOWER than the temp you'd like to monitor. The highest temps will be at the front of the head where coolant is leaving the block and heading to the rad for some thermal monkey-business. That's because the coolant picks up more heat as it moves through the heads.
I have a two coolant gauges on mine - one in the dash and one under the hood. I mounted both sensors in the side tank of the radiator just below where the upper hose (hot coolant leaving the engine) connects. They read within a few degrees of the temp the ECU sensor (U.S. driver's front head) spits out on my hand held.
If it were mine, I'd want that gauge sender relocated. My motor very similar to yours -- crate LS3 circa 2015.
I have a two coolant gauges on mine - one in the dash and one under the hood. I mounted both sensors in the side tank of the radiator just below where the upper hose (hot coolant leaving the engine) connects. They read within a few degrees of the temp the ECU sensor (U.S. driver's front head) spits out on my hand held.
If it were mine, I'd want that gauge sender relocated. My motor very similar to yours -- crate LS3 circa 2015.
Be sure that WHERE you drill/tap the pump is the part of the pump where the coolant's LEAVING the engine. Otherwise you're right back in the same soup. FWIW, if you position your sensors in the radiator adjacent to the upper radiator hose (where hot coolant leaving the engine enters the radiator) your readings will reflect the same temps that the ECU sensor sees. As you can see now - there's no such thing as a 'constant' temp in an engine or a radiator. Coolant temps vary depending on where you sense them. Good luck with your solution.
