Knock sensor flush
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Joined: Oct 2012
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From: weems va
Knock sensor flush
I have put this off since getting my 93 and now im glad i did it the RIGHT way. Pulled knock sensors and i cant describe what dribbled out! I have been told to do a flush the right way that you should pull sensors well i flushed without removing them 2 times and thought i had most of the sh.. out of the system..NOT. Not the most fun job but well worth the trouble. Put new sensors in while i was at it. Dave
Safety Car
Joined: Aug 2002
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From: SANTA CRUZ CA
Good post, Dave. As a respected poster, your info will help others to properly flush the block. First timers should be warned not to be directly under the holes when the sensors are being removed. That is really nasty stuff that oozes out.
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From: weems va
Thanks Don, nasty dosent do it justice! And ive been riding around with that stuff running through the block! It kind of looked like rusty cottage cheese. Whats surprising is i couldnt tell how bad it was just looking in the tanks?Also used distilled water with dex-cool. I let her come up to temp cool down topped off tank and thats it. Not sure why they have those bleeder screws but i havent felt the need to use them. Maybe i should but the air seems to come out on its own? Dave
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crikee i did my 85 and pulled the knock sensor and got drenched
Question for the OP, are you going to do a flush now? Mine is still sitting empty and will be doing flush shortly. What type of flush do you? I will be flushing, then draining they system again by pulling the KS out and then refilling with 50/50 green coolant.
Cheers.
Safety Car
Joined: Aug 2002
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From: SANTA CRUZ CA
squirt water from the garden hose into the block several times. It takes more than just gravity flow to remove the sediment. Once
the water looks relatively clean flowing from the knock sensor hole, replace the sensor, fill the system, run the engine until the tstat
opens, then open the pet-**** at the bottom of the radiator and drain. You are just draining the radiator, but by repeating the process,
the water-flush is cycling through the engine. There is a flush solution available....check it out.
Repeat the fill-and-drain operation several times until the water looks clear. Fill with coolant......
Last edited by don hall; Nov 10, 2014 at 12:03 PM.
Safety Car
Joined: Aug 2002
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From: SANTA CRUZ CA
Thread Starter
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Joined: Oct 2012
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From: weems va
yes great post. not too tough to pull the knock sensors (on my 85 there is only 1 knock sensor in the block on the passenger side)...but very hard not to get drenched in the process and it is DISGUSTING.
Question for the OP, are you going to do a flush now? Mine is still sitting empty and will be doing flush shortly. What type of flush do you? I will be flushing, then draining they system again by pulling the KS out and then refilling with 50/50 green coolant.
Cheers.
Question for the OP, are you going to do a flush now? Mine is still sitting empty and will be doing flush shortly. What type of flush do you? I will be flushing, then draining they system again by pulling the KS out and then refilling with 50/50 green coolant.
Cheers.
Team Owner
Joined: Aug 2004
Posts: 21,543
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From: Park City Utah
What Seabright said, but one other way to do it that is even faster, IMO, is drain the rad and the Knock sensors), leave the sensors out. Remove a heater core hose, force garden hose water through that. That will flush the heater core too (not mentioned thus far), and the block all at one time. Then do the same w/the radiator. Let drain, close/replace all plugs, fill and run.
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Joined: Aug 2004
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From: Park City Utah
^True, but I bet that affects your sensor's ability to work, and also, on an LT1, you'll only (mostly) be flushing one side of the block. Doesn't do anything for the heater core, either, unfortunately.
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Lol.
cliff doing your suggestion, sans the driving around part lol.
j/k.
i assume i fill rad, screw in the water to block, start car, ipen rad drain, and let it go into block as it comes out rad, then when water is clear out of rad, pull water from block, reinstall ks, shut rad drain, empty reservoir, fill rad with 50/50 , fill reservoir with 50/50, turn on car (block will be devoid of anything at this point?) watch for system to draw down the reservoir level as tstat opens, fill reservoir with more 50/50 as needed until the level stabilizes at warm level marking on reservoir tank?? is that right? And do i need to do anything for burping or will that method be allright?
going to fill my 85 block this saturday. been empty for a while after gettin drenched by brown sludge from ks removal.
j/k.
i assume i fill rad, screw in the water to block, start car, ipen rad drain, and let it go into block as it comes out rad, then when water is clear out of rad, pull water from block, reinstall ks, shut rad drain, empty reservoir, fill rad with 50/50 , fill reservoir with 50/50, turn on car (block will be devoid of anything at this point?) watch for system to draw down the reservoir level as tstat opens, fill reservoir with more 50/50 as needed until the level stabilizes at warm level marking on reservoir tank?? is that right? And do i need to do anything for burping or will that method be allright?
going to fill my 85 block this saturday. been empty for a while after gettin drenched by brown sludge from ks removal.
Safety Car
Joined: Aug 2002
Posts: 3,842
Likes: 230
From: SANTA CRUZ CA
cliff doing your suggestion, sans the driving around part lol.
j/k.
i assume i fill rad, screw in the water to block, start car, ipen rad drain, and let it go into block as it comes out rad, then when water is clear out of rad, pull water from block, reinstall ks, shut rad drain, empty reservoir, fill rad with 50/50 , fill reservoir with 50/50, turn on car (block will be devoid of anything at this point?) watch for system to draw down the reservoir level as tstat opens, fill reservoir with more 50/50 as needed until the level stabilizes at warm level marking on reservoir tank?? is that right? And do i need to do anything for burping or will that method be allright?
going to fill my 85 block this saturday. been empty for a while after gettin drenched by brown sludge from ks removal.
j/k.
i assume i fill rad, screw in the water to block, start car, ipen rad drain, and let it go into block as it comes out rad, then when water is clear out of rad, pull water from block, reinstall ks, shut rad drain, empty reservoir, fill rad with 50/50 , fill reservoir with 50/50, turn on car (block will be devoid of anything at this point?) watch for system to draw down the reservoir level as tstat opens, fill reservoir with more 50/50 as needed until the level stabilizes at warm level marking on reservoir tank?? is that right? And do i need to do anything for burping or will that method be allright?
going to fill my 85 block this saturday. been empty for a while after gettin drenched by brown sludge from ks removal.
Team Owner
Joined: Aug 2004
Posts: 21,543
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From: Park City Utah
Sounds confusing to me. You have the fill procedure right, IMO.
For the flush, the goal is to run fresh water through the entire system, until all the old coolant and any contamination is out.
One way is to drain, fill w/water, run, repeat until the water is clean. Then drain and fill w/coolant mix.
The other way is to flush w/a hose....car not running. My recommendation for this was to plug your garden hose into your heater hose, which will push water though the heater core, water pump, heads/block and out the knock sensor holes. It gets every part of the cooling system and can be done in one operation rather than multiple fills/drains. When you shut the water off, the car drains though the knock sensor holes. Then fill w/coolant mix.
Either way works just as well. If you're using a garden hose, car doesn't need to be running. If you're using the fill 'n drain, you want to run it to mix it up in there, then drain.
Melting Slicks
Joined: Jan 2008
Posts: 2,054
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From: AZ
Originally Posted by Cliff Harris;1588237786assemble these bits and pieces of plumbing.. you can attach your garden hose directly to a knock sensor hole:
[IMG
[IMG
http://www.misterpeachy.com/VettePics/Cooling_System_Flusher_Parts.JPG[/IMG]
Usually, HD has all but one or two of what I need.
