Coolant problems
Safety Car
Joined: Nov 2008
Posts: 3,707
Likes: 550
From: Seattle Washington
OK so I have read a couple of the Threads on cooling problems and Yes I now have a few of my own. 1996 LT4. The car has sat for a Year with out being driven. As soon as I started it I got a low coolant light and have had it ever since. I have driven the car a number of times and it has had a number of heat and cool cycles overnight. I have opened the bleed screws and pulled the vent line off the top of the Radiator and have yet to see a bubble. I have removed the pressure cap hot and cold and its holding pressure and the Coolant is right there. OK so I must have a bad sensor. But wait, although its always 187 wile on the highway I have seen it get up to 240 wile in traffic. Wile were at it I haven't noticed my Cooling Fans coming on. But maybe they are. I read that the Low Coolant sensor is on the Radiator but I'm not finding it. Why is it on when everywhere I look all is Full ? Sounds like this is somewhat common but I haven't found out why.
Race Director
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
Sometimes the blade on the sensor gets gunked up and it doesn't work. It should be in one of the tanks of the radiator. Drain some coolant and take it out and clean it.
Mine has a single green wire. The radiator setup was changed in 1990 to the slanted orientation and mine is the old vertical orientation. This is what mine looks like:
Mine has a single green wire. The radiator setup was changed in 1990 to the slanted orientation and mine is the old vertical orientation. This is what mine looks like:
Team Owner
Joined: Sep 2003
Posts: 20,170
Likes: 672
From: Freedom is never more than one generation away from extinction.
St. Jude '03 thru '24
Thats a good suggestion Cliff.
I have tried to remove the sensor twice, and broke it twice.
I'd also recommend to have a spare onhand before trying this inspection.
I have tried to remove the sensor twice, and broke it twice.
I'd also recommend to have a spare onhand before trying this inspection.
Safety Car
Joined: Nov 2008
Posts: 3,707
Likes: 550
From: Seattle Washington
Turns out on my 96 the sensor in the bottom of the Surge Tank. ( the one with the radiator cap) It is a non serviceable part, so the way to replace it is to buy a whole new tank. I was surprised the Rock Auto is selling the Tank for $45, I expected it to be much more. I removed the tank and hosed it out but there wasn't any sludge that came out, looking in the openings there is no way to see the sensor it self. I put it all back together wile I wait for the new tank. For a quick fix the Dash Light will go out if the Sensor is just un plugged. I also ordered a new Delco RC 27 Cap, and it looks as though its been up dated to some sort of plastic gizmo. I hope its not, as I intend to keep my car all stock looking as its a GS Convert.
Melting Slicks
Joined: Aug 2008
Posts: 2,082
Likes: 50
From: Palmdale CA
im not trying to start a big thing but in over 35 yrs both as a tech and as a certified gm trainer i have never heard such a thing in my life untill i cam on this site. Pleas tell me what raising the front of the car does or even packing. all closed systems get the air out on their own. if you dont belive me read your fsm or i even think it covers the cooling system in the owners manual. You can have a massive air pocket when installing a new pump. the best thing to do with this is 1 make sure you dont let the car get to hot.(the temp gauge may be off at this point because fluid is not hitting it) add fluid till full when you think the cooleant is up to temp pump the upper hose this pulls cooleant across the stat. if at this point the stat does not open shut the car off let it sit for a little while then re start and add cooleant as needed. once the stst has opened (the upper hose will be hot) top off the fluid in the rad and in the recovery tank test drive then refill as needed
This has served me well for over 30 years..
