Cooling System Fluid Change 1993 LT-1

[bstie]

Anyone have any experience changing Anti-freeze/Coolant on an LT-1? Specificall on a 1993..............

Reason I ask is that I thought it would be pretty straight forward, until I read the Factory Service Manual and sounds like a challenge.

Specifically, it mentions to remove the Knock Sensors and open the bleed screws? Will these knock sensors come out fairly easy once I find them? Also, how many bleed valves must be opened to release the air pockets and where are all of them?

I was thinking about letting my local Chevy dealer take the challenge, however, I like the satisfaction of doing things right the first time.

Any thought or suggestions greatly appreciated.

Brian

 

[c4cruiser]

The knock sensors do come out but you have to get a 22mm socket for them. They are located at the bottom center of the block just behind the motor mounts. Expect a lot of coolant! Don't use any thing like teflon tape when re0installing as the threads are the ground for the sensors. A bit of anti-seize is all that should be necessary.

The two bleed valves need to be open when refiling. Once a steady stream of coolant comes out the vents, close them. Be careful not to let coolant fall down on the Opti-spark! Use some amuminum foil under the valves to form a drain chute to take any coolant away from the Opti.

While the maual says to run water through 3 times if you are doing a complete flush, if the old coolant is in good shape and after the 2nd flush, the water coming out is clear, you should be able to install new coolant. Don't forget to use teh distilled water as called for. The cooling system "pellets" are no longer recommended by GM so there is no need to add them.

If the car still has the original hoses, now is the time to change them. IMHO, the important ones are the upper and lower radiator hoses and the small TB bypass hose. Check the metal tee fitting for any signs of corrision or rust. The heater hoses are pricey and you have to pull the expansion tank to change them.

Add the 2 gallons of "green" coolant and top off with distilled water as the manual states. Don't forget to clean out the overflow tank and fill it after the final filling of the expansion tank and the burping process.

 

[Vettelt193]

i have flushed and not removed the knock sensors.... the 2 bleed valves are nothing to worry about though


Basically, i drain the radiator the best i can... replace with fresh water... bleed, then run the car. same thing over a couple of times until things are running pretty clear.... then, i drain the radiator and fill with mainly, or all, coolant. you should have close to a 50/50 mix by then. Although I currently run less coolant than water, more of a 80/20 mix, for cooling purposes.

 

[Robertwav1]

Don't let the dealer do it....I had them do mine...thing is....they never did it and said they did. The overflo tank was dirty, which I had discovered later and the coolant was no different in color then before I had it done. I drain off the top tank every so often and refill. Take out the overflo and clean it. If you do this quite often the fluid is eventually changed without the possibility of trapped air or flooding out the opti. Seems like all the years I thought I was doing a good job on flushing out a cooling system....I would loose a water pump or the radiator would start to leak. I don't know...I guess it was the shock to the system. I've also heard about the hazzards of flushing transmissions also...I figure it applies here. Just my opinion....I'm sure many will disagree with me on this.

 

[reefdiver]

I had mine flushed at the dealer. It's a small dealership,and they permit me to go back into the shop area to see things firsthand. For about $50 they flushed it-cleaned out overflow res,and even did a few other little things (no chargefor them), so I came away happy. As for the tranny flush I'm still debating that move. The dealership told me there was no need to do it. A guy who owns a performance car repair shop told me I'm crazy if I don't have it done.Anyone have any experience with having the tranny flushed? Pros--cons? BTW..I'm having NO trouble with the tranny-shifts smooth and at the right rpm's.

 

[Sone]

Bstie
I just had my 93 powerflushed by the dealer for 89 dollars.
I think it is worth it. I like my local dealer, plus they have a guy who only works on Corvettes. It needed flushed and it runs a bit cooloer now. I do everything else on the car myself, dealer does brakes and flushes.

I have done it before, but for the price I lean toward the PowerFlush. Just my opnion..
Good Luck with it either way!!!!