I flushed the cooling system in my 96 last night and now have a Low Coolant light. I've "burped" the thermostat housing several time, each getting ot a little air, but the light remains. Any ideas?

Mark

 

Guess you just have to rev it up a bit. Held it > 2000rpm for a minute o so and it went away.

Mark

 

Ever since I did my water pump I get an intermittent light. I've burped it several times and still there. When I rev mine it doesn't seem to pull coolant from the resivour (level in the radiator drops when reved).

 

Two different systems here, and handled differently. On the 96, there are bleed in the cooling system, have you bled the air out of the system using the bleeds?

On the 88, the system must be "packed" by idling at about 2K and filling, then putting cap in place and filling overflow. If this doesn't solve it, there is a mod to the sensor that can be done.

 

When I flushed my cooling system last year I placed a rag under the thermostat housing and ran it up to op temp, loosening the bleed screw every few minutes, it would release quite a bit of air... I left the reservoir cap off and filled it as I purged the system... You'll lose just a little bit of coolant, but don't tighten the bleed screw for a minute and you'll see that the small stream of coolant will be interrrupted by air pockets escaping...

 

you may find that running the heater for about 5 minutes will help.

Also, I found that about a quart was sucked out of the overflow the first 2 times I drove it after flushing. Keep an eye on it.

 

I was gonna make a new topic on this one, but this seems like as good a place as any since it is very much related. Since I did my mods I've been running pretty much straight water, the only antifreeze is what wasn't drained out of the block. I was going to convert to dex-cool since the cooling system was in great shape.

Yesterday with the car cold I pulled the drain from radiator and coolant started to trickle out. I put a pan under it and then pulled the pressure cap. That made the coolant pour out. As I expected it was pretty thin, mostly water. When the coolant flow slowed down, I switched on my electric water pump. I then took a water hose and put it in the fill location, turned it on so that it would keep up with the water flowing out, but not overflow the fill. I eventually got rid of all the green, then it turned kinda milky white, then it was pure clear water.

Note, on the LT1 it would seem that the way the coolant is routed around that you CAN actually flush out the block this way, or get it as close as you are going to get without pulling knock sensors. Anyway, after I got clear water I let it run for several minutes. I then turned to the surge tank and pumped out as much as I could and then put the water hose in there. I turned it on full blast and just let it overflow, there aren't any electronics around so it was fine. When all I got was clear water in there I then pumped out as much as I could from there.

I turned off the hose and let everything drain one last time. Then I put the drain back in the radiator and with the water pump still running started to add dex-cool. Cooling capacity is supposed to be 17.8 quarts, round it to 18 quarts and you would want to put in about 9 quarts of dex-cool and then top it off with water. At 8 quarts (two bottles) it was getting full. I got about 1 and 3/4 in there before I had to start getting creative. I let the water pump continue to run and it slowy bled off air. I shielded the opti and bled the air off manually several times. I eventually got the whole second bottle in the car, a combination of being in the surge tank and being in the actuall fill. It was FULL, so I put the cap on and then fired it up. I let it idle up to operating temp and let the thermostat open, etc. Not once did I have to add water or bleed the air off. No lights, works just fine.

I drove it around for a couple of miles and then let it cool enough for me to open it. It's still full and it's orange just like a new car, I really think it did a good enough job flushing the block. If it didn't it certainly would if I was to do it again. Anyway, the moral of my slighty too long story is that it's not the hard to flush and fill, but the electric water pump makes the job MUCH easier.

I know you guys think I'm electric water pump crazy, but it allowed me to completely flush the system without getting burned and without having to add any extra coolant on the side of the road.

 

I'm experiencing that same problem with my 96. Yesterday, I noticed that the intermittent light comes on 100% of the time whenever I accelerate hard. I have not noticed any problems with the motor running hot, so the light is more of an annoyance than anything else. Could this be an issue where coolant is not pulling from the resovoir (sp?) when revved?

I did have this same problem about 2 months ago when I picked up the car. The dealer took it in for service and said that the sension was loose. After that, it seemed like it was fine for a couple of days and now it's back again.

Scott