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Well I got my new radiator shipped in today from Rock Auto with new Knock Sensors as well. I went to remove my old knock sensors this evening with a 22mm socket and got the drivers side out fine with a little effort. I am confused though because no coolant came out? Some should have correct? I was expecting it to come gushing out like some have said. Could it be that blocked up that something was clogging the hole? I did not have room for the car in my shop so it was outside and it was getting dark and had limited lighting so I could not tell. The sensor had some fluid on the tip I could see but that is all, just wet. I will get a better view tomorrow.

When I went to remove the passenger side Knock Sensor it is just spinning. I have a good bite on it and the head is just turning within the sensor. I have heard some say they have had issues with this as well. Should I try to get a wire welder in there and tack it back and try to remove it or what is my best option? I thought about trying a chisel to see if I could get some bite on it but I am afraid I will make it worse. Should I just let it go and forget about it? I would like to get it out and do it correctly especially since I have new knock sensors and a new radiator.

Any helpful tips would be greatly appreciated. As usual if there is going to be problems it will be with me. LOL.

Also wanted to ask how I can flush it from the top side? I am sure this is a stupid question but I had the thermostat out should I not be able to run water down the water pump hole and it flush through and out the knock sensor that is out on the drivers side or would the water pump have to be pumping or pulled off the motor for it to flow through?

Any suggestions on what my next options should be? I am truly at a loss and very frustrated.

Thanks so much!
 

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Well I got my new radiator shipped in today from Rock Auto with new Knock Sensors as well. I went to remove my old knock sensors this evening with a 22mm socket and got the drivers side out fine with a little effort. I am confused though because no coolant came out? Some should have correct? I was expecting it to come gushing out like some have said. Could it be that blocked up that something was clogging the hole? I did not have room for the car in my shop so it was outside and it was getting dark and had limited lighting so I could not tell. The sensor had some fluid on the tip I could see but that is all, just wet. I will get a better view tomorrow.

When I went to remove the passenger side Knock Sensor it is just spinning. I have a good bite on it and the head is just turning within the sensor. I have heard some say they have had issues with this as well. Should I try to get a wire welder in there and tack it back and try to remove it or what is my best option? I thought about trying a chisel to see if I could get some bite on it but I am afraid I will make it worse. Should I just let it go and forget about it? I would like to get it out and do it correctly especially since I have new knock sensors and a new radiator.

Any helpful tips would be greatly appreciated. As usual if there is going to be problems it will be with me. LOL.

Also wanted to ask how I can flush it from the top side? I am sure this is a stupid question but I had the thermostat out should I not be able to run water down the water pump hole and it flush through and out the knock sensor that is out on the drivers side or would the water pump have to be pumping or pulled off the motor for it to flow through?

Any suggestions on what my next options should be? I am truly at a loss and very frustrated.

Thanks so much!
On th side that you got 1 KS removed, there is most likely a lot of crud blocking the hole. Take a small screwdriver or awl and poke it in the block which should open up and allow coolant to run out.

On the passenger side KS, sounds like the lid of the KS has separated from the body. It does not take much torque on the KS for this to happen. It may be real helpful to take a few extra minutes and remove the starter to gain some valuable working room in this area. Then as you suggested you could try to tack weld the lid back to the body of the KS. If you do this, try to turn the sensor in clockwise, just a little first and then back it out. At the first sign of resistance, move it back in clockwise and then back it out a little further. Your fighting with the junk in the system along with the threads in the block to remove the KS.

If all else fails, then it's time to get creative with a pair of vice grips or similar on the body of the KS. At this point, I would do whatever you can to get the old KS out of there. It is probably no good now that the lid has separated from the body. When reinstalling, there should already be sealer on the threads. DO NOT use Teflon tape or other sealant as this will affect it reading properly. Install torque on these is very low too.....I believe it's only 14' lbs.

To flush the block, yes filling from the WP Tstat housing should work. You just need to block off the heater core ports and rad port to fill the block. I assume these are all disconnected anyway for flushing. I like to block off the KS ports on the block to let the block fill and then remove the KS to allow it to FLuuuuush real good. Do this a few times til the water appears clear. Once done refill with a 50/50 mix of distilled water and coolant. A complete flush will take about 2 gallons of H2o and 2 gallons of coolant.
 

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I had the block drain plug hole do that on my 83 GM V8 driver side .. back then no KS just a pipe plug. when I stuck a screw driver in the hole the block drained and had casting sand in it which caused the blockage.

on my 96 I never had any issues removing the KS but I removed them when the vehicle was 3 yrs old. also I am the only person that's works on it.

over torquing maybe the problem on why it broke. using various tools you should get it out .

I use permatex MACHINE thread sealant on the threads and torque to about 10 ft lbs being careful NOT to shock/drop the sensor OR bang hit it...

this type sealant is basically paint ..will not effect sensor operation in any way and no leaks. using a round pipe brush work the block threads so clean less chance of leak.

on coolant I use 2.5 gallons of antifreeze and 1.5 gallons of distilled water. it may take a extra QT if you blow out the heater core which it what I do every time this is done.
 

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Yep, just did mine. Barely inserting a small screwdriver into the DS had it gushing. The PS side came out easy for me, but there was nearly no water left at that point. A cup maybe. Doubt if even a pint.

If you however want to tackle it, you may want to try a plumbing wrench. Name escapes me at the moment, but it's a spring loaded jaw that's use to get the faucet nuts at the back of a sink. Acts like a pipe wrench, self locking, but the handle is parallel like the socket extension would be. And the end has a T bar.
 

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Discussion Starter #7
Interesting! Has anyone tried a Basin Wrench on this before and had it work? Would I be better off trying that first before welding it? Thanks for the info!
 

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Interesting! Has anyone tried a Basin Wrench on this before and had it work? Would I be better off trying that first before welding it? Thanks for the info!
Have not as I've been fortunate to get them out with a socket/ratchet. As you probably know laying under the car and looking at the sensor, having a wrench that has a flex head could be very helpful. The angle of the block where the sensor is compared to the angle of the oil pan, does not make it easy to attack the KS housing from the side. A pipe wrench that does not flex could make this difficult from the underside of the car. Maybe the angle is easier from the top but what you have to remove to get at the KS does not make this feasible.

Basin wrenches are fairly inexpensive so it's worth giving it a shot. But if you have access to a welder and the KS is most likely toast anyway, why not just hit it with a Few welds? The easiest way to get these out is to just use the socket on the KS lid. Just try to tighten it in a little first and then try to back it out. Once it breaks free, it should come out pretty easily as they are a NPT thread and have a slight taper to them.

If the KS already has what appears to be sealant or what may look like a thread locker (reddish color), this is all the sealant you need. No need to add more and I've just reinstalled them a few times with the existing sealant and they haven't leaked yet. So I wouldn't consider adding any additional sealant to the threads. All the new KS's I've seen already have something applied to them. Take a close look at your new KS to confirm this.
 

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Discussion Starter #9 (Edited)
Thanks 4Door. It is going to have to be a welder indeed. I sit here humbly typing this having failed yet again another night. Tried the Basin Wrench (was not large enough to bite on it), Vice Grips a no go. Welding is definitely the route to go. So did you just tack weld it on the very outer edges like on three sides then?

The good news is I got the starter off but now am wondering if I should replace it since it has not been replaced in the 12 years I have owned the car. If so what is a good brand to go with?

I have a new Hobart wire welder that I have not put to use yet, need to get an argon tank and also had a pacemaker put in and I need to be careful welding. Been using my Lincoln Ranger 8 Stick so I guess this will give me a good reason to purchase a tank and get the MIG set up. Would be much easier and cleaner to hit with the wire welder I am sure than stick right? Or do you think I could hit it okay with the stick? I am just thinking slag wise.

Did you actually use a torque wrench or will I be safe just getting them snug? 14' lbs is not much. I would have to get a torque wrench since I don't currently have one.

I poked a small screw driver in the hole as suggested and it broke through all the gunk and a ton of coolant came out. Will feel great to get it all out and this all put back together. Thanks again for all the help!
 

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. So did you just tack weld it on the very outer edges like on three sides then?

The good news is I got the starter off but now am wondering if I should replace it since it has not been replaced in the 12 years I have owned the car. If so what is a good brand to go with?

Would be much easier and cleaner to hit with the wire welder I am sure than stick right? Or do you think I could hit it okay with the stick? I am just thinking slag wise.

Did you actually use a torque wrench or will I be safe just getting them snug? 14' lbs is not much. I would have to get a torque wrench since I don't currently have one.

I poked a small screw driver in the hole as suggested and it broke through all the gunk and a ton of coolant came out. Will feel great to get it all out and this all put back together. Thanks again for all the help!
Been fortunate that mine have always come out with just using the socket, so never had to weld them before. But seems like to me whatever you can reach up in there with would be your best option. IIRC And you look at your new KS you will see how the top/lid is placed into the KS body, then the edges of the KS body are bent over the lid and believe there are then just 3 or 4 tack welds at the seam. Don't think it really matters how pretty is as long as it holds well enough to wrench it out of there.

I did use a small 1/4" torque wrench that is in inch pounds to get these in. You could probably "ball park" it by hand if you have experience doing this. But really why, when you could pickup a torque wrench fairly cheaply at a place like harbor freight. Sure it may not be as accurate as a snap-on, but they work pretty well and seem ok for the average wrencher.

On the starter....why bother if it's working fine now? Sure it's old, but if it ever does fail replace it then and its (to me) such an easy replace anyway. Not to mention the replacemnt stuff isn't as good sometimes as the original. If you do replace, seriously consider getting the Corvette Starter for the LT1 which is a direct Bolton.
 

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Discussion Starter #11
Awesome! Some great tips. Thanks again. I typically always try to be preventative and would have replaced the starter but it seems like you said the replacement stuff is not as good as the original and it will always come back to bite me. Thanks for the help. Getting a bottle for my welder tomorrow after work so hopefully will have it knocked out. I will get me a cheap torque wrench at HF Tools. Thanks once again for all your help. Hopefully I won't have to bother you anymore. Much appreciated!!
 

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Awesome! Some great tips. Thanks again. I typically always try to be preventative and would have replaced the starter but it seems like you said the replacement stuff is not as good as the original and it will always come back to bite me. Thanks for the help. Getting a bottle for my welder tomorrow after work so hopefully will have it knocked out. I will get me a cheap torque wrench at HF Tools. Thanks once again for all your help. Hopefully I won't have to bother you anymore. Much appreciated!!
don't replace starter if good. just clean it up and tighten the connections on it.

I replaced my starter because it was not cranking when around zero deg F. after 6 months I brought it back it was so loud cranking got louder and louder lifetime warranty new . got all my money back original in it now works good above zero F.

the forums are here to help owners make repairs . also save money and time trying to find out whats going on...

some vehicles you will not find any help forums .
 

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A quick slice with a saw, then hit it with an air chisel to collapse, and you'll be able to pry it out.

For future modders: don't change knock sensors unless there is something wrong with them ;)
 

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Awesome! Some great tips. Thanks again. I typically always try to be preventative and would have replaced the starter but it seems like you said the replacement stuff is not as good as the original and it will always come back to bite me. Thanks for the help. Getting a bottle for my welder tomorrow after work so hopefully will have it knocked out. I will get me a cheap torque wrench at HF Tools. Thanks once again for all your help. Hopefully I won't have to bother you anymore. Much appreciated!!
Glad to help and hopefully it saves you some aggravation. Another suggestion and while the starter is out, don't just hook up the cables when done. Instead, take some time to clean both sides of the Starter terminals on the harness. I usually take some fine (1000 grit) paper and clean both sides of the metal terminals that connect to the starter. Clean the Start posts as well and then use a bit of Dielectric Grease on the connections to help keep them clean. Not a bad idea to clean up the other Engine grounds in the engine bay along with the battery terminals while you're at it.

A quick slice with a saw, then hit it with an air chisel to collapse, and you'll be able to pry it out.

For future modders: don't change knock sensors unless there is something wrong with them ;)
Curious if this does happens and I need to resort to some other method to remove. Are you saying to slice across the top of the KS body? Just having trouble picturing in my mind what you were describing. If I ever get stuck, it would be nice to have another method to get these buggers out of the block.

BTW, the knock sensors can be tested with a DVM across the plug lead and the Body which acts as ground for the circuit. I have it documented here somewhere but believe you should see about 500 ohms across the sensor.
 

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Discussion Starter #15
Well got the KS out. It was not fun. LOL.. After welding it I got the wrench on it and the whole head of the KS popped off. Only thing left was the threads in the block sticking out. So took 1/2" extension and welded it up on the stud left in the block and finally got it backed out. Whew! I was sweating it.

Got everything buttoned up. Filled the engine block with 50/50 own mix of antifreeze till it was up to the top of the water pump housing where the thermostat sits. Put new hoses and thermostat in and then filled the overflow tank. Started her up everything seems great.

Only issue now is my low coolant light will not go off? I drove it for about an hour and the temperature is staying right in range. Checked the tank both hot and cold and it is where it should be do you think my sensor is bad? When they go bad will they stay on? I disconnected the battery again thinking maybe it will reset something but it never did. I can unplug the sensor plug and the light will go off. Am I missing something? Maybe pressure built up or something? I even loosened the brass screw on the thermostat housing to see if that would make a difference and just antifreeze starting coming out.

Do you think I am okay and its just the sensor or any other suggestions possibly? Cleaned up the old starter like suggested and it is working fine. Thanks again for all the help and information. Let me know what you think about my low coolant light. Thanks
 

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Most likely the sensor in the reservoir is stuck somehow. Did you not flush and clean the reservoir while the system was drained? The reservoir gets a lot of junk in it and this can cause the sensor to stick and not make contact.

If you're sure the system is bled properly and at the correct level, then there is not much else you can do. You can try to tap on the tank near the sensor location to see if that frees up the sensor. If not, it may later decide to start working after driving it for a bit like mine did recently. If nothing else works then youre only other option is to replace the reservoir since the sensor itself is not replaceable.
 

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Discussion Starter #17
Yeah, I flushed and cleaned out the reservoir really well. I wonder if maybe when flushing it something got stuck in there that did not work loose and just happened to catch right on the sensor then? That is crazy, they don't sell just the sensor at all? How sad. Hopefully Rock Auto carries replacement reservoirs then at a decent price. I will give her a tap and see what happens and then drive it some more to see if it works loose and go from there. I guess just unplug it until I get a new one. I hate idiot lights but it is good to have if you need it letting you know of a possible coolant leak. Thanks 4Door, appreciate it as always!
 

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I just checked on RA and they show one for our cars. The plug looks different though. This one looks much larger and the plug looks to be on the side instead of the bottom? So you think this is an error?

1994 CHEVROLET CAPRICE 4.3L V8 Coolant Level Sensor | RockAuto
Something is not correct with that picture of the sensor in your link. That looks more like a sensor that goes into the radiator side tank. I recently replaced one that looks just like it on my 92 Buick Regal witha 3.8L engine.

On our cars (94-96 L99/LT1) the sensor is molded into the reservoir and is not something that can be replaced. If the sensor dos not free itself up, then your only options are to remove, flush the tank and see what happens. If that does not work, then the only other option is to replace the entire reservoir.
 

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Discussion Starter #20
Yeah, I agree. I did not think it looked correct and went home after work last night and verified. That is completely different. Good to know. Thanks again.
 
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