LS376/480 Cooling Issue
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Joined: Apr 2015
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From: Socal
LS376/480 Cooling Issue I am having an odd cooling issue with my LS3. Motor is a brand new crate motor. At idle and on the road, if my rpm's are low the motor will build heat and run up to about 220 and beyond if I am not careful. If I run the rpm's up to over 3k, it cools right back down. It has the gmpp cts-v style accessory kit so as far as getting something in backwards or not being the right "size," it seems that shouldn't be the case. Idling, around town driving, or freeway driving doesn't make any difference. rpm's seem to be the only thing that will cool it down.
The cooling system is a 4 core radiator, surge tank and front 2 steam ports routed to the surge tank.
Any thoughts? The obvious seems that the water pump isn't circulating fast enough at low rpm's but that doesn't make sense given I am using the recommended gmpp combination of parts.
The cooling system is a 4 core radiator, surge tank and front 2 steam ports routed to the surge tank.
Any thoughts? The obvious seems that the water pump isn't circulating fast enough at low rpm's but that doesn't make sense given I am using the recommended gmpp combination of parts.
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From: Socal
Autometer aftermarket gauge to determine temp plumbed off the top back of the intake. Computer kicks fan on at 207 and my gauge reads 200 when it kicks on so it is close but not exact.
The computer was provided by Speartech. I originally used gmpp everything but had lots of issues with the wire harness. Dumped all of that and am now running a Speartech harness and computer.
The computer was provided by Speartech. I originally used gmpp everything but had lots of issues with the wire harness. Dumped all of that and am now running a Speartech harness and computer.
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Do you have the correct sending unit? The autometer version I have reads head temperature, not water temp. Not sure what the difference is as it screws into the rear port like yours, but the temp jumps like yours also. I hooked up HPTuners and the unit in the drivers side head as read by the computer does not jump around like the Autometer version. Fan kicks on at 210 and off ar 200 if I recall.
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Joined: Apr 2015
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From: Socal
I definitely have the correct sender. It took me a while to sort out where I was going to put it and was careful as I ordered it since I was matching the gauge I already had.
I also know my temps are actually changing because when it gets higher it will release the cap on my surge tank.
I also know my temps are actually changing because when it gets higher it will release the cap on my surge tank.
I know this sounds weird but I read a thread stating that there is a difference of water temp between the left head and the right head temp at the temp sensor holes. The LH being the correct spot for the sender. If I remember correctly it was about 20* hotter at the RH near the fire wall I think.
Someone correct me if I'm wrong.
Someone correct me if I'm wrong.
I know this sounds weird but I read a thread stating that there is a difference of water temp between the left head and the right head temp at the temp sensor holes. The LH being the correct spot for the sender. If I remember correctly it was about 20* hotter at the RH near the fire wall I think.
Someone correct me if I'm wrong.
Someone correct me if I'm wrong.
I definitely have the correct sender. It took me a while to sort out where I was going to put it and was careful as I ordered it since I was matching the gauge I already had.
I also know my temps are actually changing because when it gets higher it will release the cap on my surge tank.
I also know my temps are actually changing because when it gets higher it will release the cap on my surge tank.
Thread Starter
Teching In
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From: Socal
That might explain the difference between when my fan kicks on and what my gauge is reading. The sensor that sends a reading to the ecm is on the drivers side front. The sensor for my gauge is on the passenger side rear.
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From: Socal
I can only get the fan to kick off when I rev the engine to bring the temps down. Otherwise it runs all the time.
Interestingly I wired in a switch on my fan to turn it off on the freeway to see if it running all the time on the freeway was necessary. It didn't change the temp at all having it off on the freeway but it doesn't drop enough to automatically turn the fan off unless I run in 4th gear and get the rpms up.
Interestingly I wired in a switch on my fan to turn it off on the freeway to see if it running all the time on the freeway was necessary. It didn't change the temp at all having it off on the freeway but it doesn't drop enough to automatically turn the fan off unless I run in 4th gear and get the rpms up.
Sounds like you have air in the system. What vehicle is this installed into?
I've had good luck with backfilling the system through the vent hose. Attach a 2 foot hose to the crossover nipple, use a small funnel. It's a slow process but works well in completely filling the block and purging any air that might be present.
Andrew
I've had good luck with backfilling the system through the vent hose. Attach a 2 foot hose to the crossover nipple, use a small funnel. It's a slow process but works well in completely filling the block and purging any air that might be present.
Andrew
