Low coolant warning light - The 1947 - Present Chevrolet & GMC Truck Message Board Network

36chevy · 08-19-2021, 11:19 AM

I have a 1982 Square that I bought with a 5.3 ls swap. The truck originally was a 6.2 diesel. The "Low Coolant" warning light is always on. Did only the diesels have this light? I need to change out my cluster and was looking for OEM replacement from non-diesel.

Will this solve the problem. I don't think the LS radiator has a spot for this type of sending unit..

Thank you

kipps · 08-19-2021, 01:24 PM

I'm just wondering if it might be worth keeping that light functional. What radiator do you have in the truck now? Does it have plastic tanks? Does it have a radiator cap on the radiator itself?

**hatzie** · 08-19-2021, 05:26 PM

The expansion tank on the inner fender of my 2005 Silverado with the LQ4 has a coolant level sensor. It's molded into the tank IIRC.

The Diesel gauges are the same as the gasoline engine rigs. I've forgotten whether the fuel gauge says Diesel or not but that's easily remedied without replacing the entire cluster.
The dash bezel with the Water in Fuel and Wait To Start lamps is what differs. Gasser bezels are more plentiful than diesels so I'd offer the diesel bezel for sale.

**Corts60** · 08-19-2021, 08:59 PM

I agree with hatzie. If you're gonna get rid of the diesel bezel, I'm sure someone will want to buy it. They are getting harder to come by.

36chevy · 08-20-2021, 11:49 AM

I assume the expansion that I have is the one that came with the 2001 Silverado. Where can I find the sending unit I don't see it? Also, did the non-diesels have the low coolant image"symbol"? I am doing most of the rewiring so It would be good to know what symbols the non-diesels actually had. Non of them are currently working except for the " low coolant" currently.

kipps · 08-20-2021, 01:17 PM

Quote:

Originally Posted by 36chevy

I assume the expansion that I have is the one that came with the 2001 Silverado. Where can I find the sending unit I don't see it? Also, did the non-diesels have the low coolant image"symbol"? I am doing most of the rewiring so It would be good to know what symbols the non-diesels actually had. Non of them are currently working except for the " low coolant" currently.

The LS-equipped trucks had a pressurized expansion tank. The radiator cap was on the tank, not on the radiator itself. This is a random Amazon pic. Note the level sensor connector on the bottom of the tank, just behind that lower outlet. I was browsing around on various electrical diagrams for these early-2000's GM vehicles, and it appears like the sensor is simply a two-wire switch that closes based on the level of coolant. I don't know if the switch closes when the bottle is full or when it's empty.

**hatzie** · 08-20-2021, 04:14 PM

Quote:

Originally Posted by 36chevy

I assume the expansion that I have is the one that came with the 2001 Silverado. Where can I find the sending unit I don't see it? Also, did the non-diesels have the low coolant image"symbol"? I am doing most of the rewiring so It would be good to know what symbols the non-diesels actually had. Non of them are currently working except for the " low coolant" currently.

I've never run my engine with the coolant low enough to discover whether the switch or lamp works or not but my truck definitely has the wiring to the expansion tank. It's a 2005 LQ4 6.0L

08-19-2021, 11:19 AM	#1
36chevy Registered User Join Date: Aug 2011 Location: Miami Florida Posts: 58	Low coolant warning light I have a 1982 Square that I bought with a 5.3 ls swap. The truck originally was a 6.2 diesel. The "Low Coolant" warning light is always on. Did only the diesels have this light? I need to change out my cluster and was looking for OEM replacement from non-diesel. Will this solve the problem. I don't think the LS radiator has a spot for this type of sending unit.. Thank you

08-19-2021, 01:24 PM	#2
kipps Registered User Join Date: Jul 2014 Location: North-central Virginia Posts: 1,104	Re: Low coolant warning light I'm just wondering if it might be worth keeping that light functional. What radiator do you have in the truck now? Does it have plastic tanks? Does it have a radiator cap on the radiator itself? __________________ 1987 C6P V20 truck, 2010 LMG 5.3, AFM delete, 2010 Camaro exhaust manifolds, 1997 nv4500, 1991 np241c, hydroboost, 2005 14bff axle & driveshaft, drop-n-lock gooseneck, 4.10 gears, stock suspension, rims, and tires. Still a work in progress. Any questions or suggestions are welcome!

08-19-2021, 05:26 PM	#3
hatzie Moderator Join Date: Oct 2008 Location: Wentworth, NH Posts: 4,977	Re: Low coolant warning light The expansion tank on the inner fender of my 2005 Silverado with the LQ4 has a coolant level sensor. It's molded into the tank IIRC. The Diesel gauges are the same as the gasoline engine rigs. I've forgotten whether the fuel gauge says Diesel or not but that's easily remedied without replacing the entire cluster. The dash bezel with the Water in Fuel and Wait To Start lamps is what differs. Gasser bezels are more plentiful than diesels so I'd offer the diesel bezel for sale. __________________ 1959 M35A2 LDT465-1D SOLD 1967 Dodge W200 B383, NP420/NP201 SOLD 1969 Dodge Polara 500 B383, A833 SOLD 1972 Ford F250 FE390, NP435/NP205 SOLD 1976 Chevy K20, 6.5L, NV4500/NP208 SOLD 1986 M1008 CUCV SOLD 2000 GMC C2500, TD6.5L, NV4500 2005 Chevy Silverado LS 2500HD 6.0L 4L80E/NP263 2009 Impala SS LS4 V8 RTFM... GM Parts Books, GM Schematics, GM service manuals, and GM training materials... 1973-1991 GM Light Truck Service, Unit/Overhaul, Wiring Manuals, Parts Books and Some 1968-1999 GM Service Training textbooks in PDF 1988-1998 GMT400 CK service manual project 1988-1993 GMT400 CK parts books. 1967-1972 GM Light, Medium, & Heavy Truck Service Manuals in PDF Please include at least the year and model in your threads. It'll be easier to answer your questions. And please let us know if and how your repairs were successful. Last edited by hatzie; 08-19-2021 at 05:32 PM.

08-19-2021, 08:59 PM	#4
Corts60 Just here to tinker Join Date: Jun 2008 Location: Holland, MI Posts: 3,697	Re: Low coolant warning light I agree with hatzie. If you're gonna get rid of the diesel bezel, I'm sure someone will want to buy it. They are getting harder to come by. __________________ 78 C10 SWB Diesel #1 (wrecked)http://67-72chevytrucks.com/vboard/s...1978+silverado 78 C10 SWB Diesel #2 (sold)http://67-72chevytrucks.com/vboard/s...d.php?t=650751 60 GMC Suburban (sold)http://67-72chevytrucks.com/vboard/s...d.php?t=445526 60 GMC 1000 (sold)http://67-72chevytrucks.com/vboard/showthread.php?t=298235 67 GMC 1500 (sold) http://67-72chevytrucks.com/vboard/s...d.php?t=803695 73 Chevy C20(Daily)http://67-72chevytrucks.com/vboard/s...d.php?t=852767 86 Suburban(summer unit) http://67-72chevytrucks.com/vboard/s...d.php?t=810697 88 Suburban 4x4(sold)

08-20-2021, 11:49 AM	#5
36chevy Registered User Join Date: Aug 2011 Location: Miami Florida Posts: 58	Re: Low coolant warning light I assume the expansion that I have is the one that came with the 2001 Silverado. Where can I find the sending unit I don't see it? Also, did the non-diesels have the low coolant image"symbol"? I am doing most of the rewiring so It would be good to know what symbols the non-diesels actually had. Non of them are currently working except for the " low coolant" currently.

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