It's not real difficult. You simply need to unhook the wire
clip that holds it in place, and pull it out of the rad.
On those vehicles, the hardest part is getting other things
out of the way, so that you can reach the sensor.
Am I going to get a Dexcool mess while doing this? It looks like my big
hands will have some problem, but with this engine the low coolant level
sensor is a must have! Thanks Ian, I knew I could count on you.
Having never seen one of these, I'm curious....
How is it that it sits inside the radiator, and is connected to wires outside
the radiator, and is still simple to remove with only a small mess and no
convoluted gasket problems and doesn't leak? NPT threads??
You might lose a bit of coolant, you can open the rad drain cock
if you want. I just put a pan under the sensor side of the rad and
catch what little drains out.
The radiator has a small round hole. The sensor has a
small tube with two o-ring seals. It just slides into the
hole and is retained by a clip that is on the sensor and
engages a section of the radiator. The sensor tube is
hollow and allows coolant into the sensor section
where it senses that there is or isn't coolant at that
Service Manual instructions
1. Drain antifreeze to below sensor.
2. Remove sensor electrical plug.
3. Lift one leg of the retainer and pull outward with a twisting motion.
4. ensure that the coolant level module seal is not damaged.
5. Lubricate new module seal with coolant
6. Ensure retainer is installed correctly and install module.
Replaced the "module" today to the tune of $41US. I am pretty sure the clip
is on right. I had to move both ends of the spring clip up above the slots
they fit in and once I thought the sensor was as far in as it was going to
get, I snapped the top clip down into place and that clipped the bottom one
too. No leaks yet and low coolant level light stays off now. The old sensor
looked like it had an oily crud all over it. I cleaned it all up with
simple green and it looks just like new. Do you think it will work again
Ian? Thanks for the info too!
If you are loosing antifreeze you better have the lower intake manifold
gasket checked. Next stop is busted cam and corroded engine. This is a major
problem on the GM 3400 engine. Do a google search on GM3400 and read the
horror stories on this engine. I did the research after the dealer wanted to
change the gasket for $800 and wouldn't explain why. I now check my level
daily and watch for oil changes and crud on the oil fill cap and
I am painfully well aware of the 3400 problems. My levels are fine and the
low coolant level light is on, so I need a new sensor. End of story.
I am thankful that you are spreading the word on these POS engines. I have
alienated many people in my "bull headed" pursuit of "Goodwill" from GM. I
figure for every person I help catch this problem during the warranty
period, I win. The way I figure, $326.50 of goodwill would have eliminated
thousands of dollars of warranty work I have helped owners recover.
The only reason I am holding this 3400 is in hopes of GM making me whole
with a recall. It will be gone however by winter.
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