i Have a 95 Lt1 and im trying to clean the old coolant and whatever else out.
I've ran the engine up to operating temp and drained radiator about a dozen times now.... and it comes out of the radiator brownish red. Ive just been putting water in it.


I know about removing the knock sensors... but i tried it... and i believe someone put locktight on those suckers. a started stripping it so i stopped, nor do i wanna break one.

Theres also the water hose "t" fitting, But water goes all over which is close to the opti, and had it connected real tight.

Ive got a bottle of prestone flush which i can use. Put don't know if i can ever get it all out cuz im not removing sensors.

IM going to put green coolant in... and dont want red stuff left in there to mix. ANy suggestion? or just keep doing what im doing?

 

The knock sensor location is the low point in the system..where ALL the gunk goes...but if its a total nightmare to get them out..I'de leave em in...the coolant doesn't have to be perfect...is there a prob that made you do this??

 

This LT1 is a used engine i put in my 87... And i get the feeling someone put dexcool in this engine.... I want to put green in it since thats what is supposed to be. But Mixing the two is a big no no.

If i put flush in this... will i be fine not hooking up a hose to it.... and just draining the radiator a few times... then add my 50/50 mix?

 

I haven't tried it myself, but someone once told me that CLR worked well to flush the whole system. Drain the existing coolant, refill and flush with water (maybe even several times) and then fill with CLR and water before flushing again with water before finally adding your anti-freeze and water combo. It sounds like a good idea but like I said, I haven't done it myself. Comments from anyone who has?

 

To piggy-back on this topic, I will ask about my 89 as well. But mine has an oil cooler...probably not on the LT1 for the OP?

On mine, I'm thinking I just have to release one of the hoses going to the oil cooler (sits above the oil adapter). I also installed a flush kit with the new engine last year. It's fitting sits on the upper heater hose near the firewall.

After draining what I can, I would assume the best approach would be to run the engine withe hose running. Let water drain out the bottom (onto the drive). Hopefully not enough AF left to "poison" wildlife or surroundings (grass)???

Should evaporate fairly quickly in hot summer sun.

Now that I think about it, does the engine even need to be run? The colder hose water will prevent thermostat from opening (unless removed). Will water flow completely thru (the motor, hoses, and radiator) using an upper heater hose and engine block drain? Who would care about any water sitting above the thermostat?

Obviously, I can run water down the radiator too.

Depending on the looks of the radiator, it might get replaced with a dual row model. I'm not happy with the current cooling for my 383 sitting in traffic on a hot day with the A/C blowing.

If I pick a new radiator, it will be either an Engineering Products or (Champion) American Eagle unit. Pricing and quality looks decent for either option with the edge to AE for customer service and price. EP has slightly better looking quality for another 23%.

Looks don't matter after it's installed though. Only performance, longevity, and price. We'll see (hopefully) tomorrow. Took the shroud off tonight.

 

On other cars that I have flushed, I took the t-stat out, reassembled the housing, and then took the upper hose loose from the radiator. Then I started the car, put a water hose in the radiator fill and let it run until it runs clear. Just make sure the hose is angled away so not to run on the opti.

 

When i spoke to the owner of the shop that built my optispark (Chris Petris) he stressed that the only way to get all the gunk out is to remove the knock sensors..there's prolly a lot of gunk in there and everytime you flush it you wash a little bit more out..you could just keep doing this but it might take a while...when refilling the system there are 2 bleeder valves that must be opened to get all the air out..one on top of the thermostat housing, the other a small screw in the front of the throttle body, driver side toward the bottom front of it...

 

On an LT1 - you have to pull the knock sensors.
Just go ahead and buy new ones - you probably need to replace them anyway.
My 92 was having intermittent knock sensor codes. When I replaced them both mine had no issues in the water passeges. New sensors cleared up the code as well.

 

I like this Idea!

I couldnt get them to turn... i could try getting a breaker bar and yank hard but i just feel its gonna strip it. One of them I can turn the inside of the knock sensor, but the outside part doesnt turn... which connects to the threaded part into the block.

 

Another reminder of what our bottom-feeder vacuums can accumulate!!!


From today on my car....