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RX300 knock sensor replacement DIY

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Old 09-01-12, 09:28 PM   #31
jrein
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After studying the DIY for changing out knock sensors, I felt it was a bit out of my league so I took it to a local shop to get the job done. They charged $1100 to do it, including an oil change. My wife picked up the car, got three miles from the shop and heard a bang from the engine compartment. There's now a loud metal-to-metal clicking from inside the engine. It can hardly idle. I fear a broken connecting rod. I had the car towed back, but the shop is closed for the holiday weekend. Do you think my engine problem is a result of an error by the mechanic? Any thoughts on things that could go wrong in a knock sensor replacement that could lead to what seems to be a serious engine malfunction? I'd appreciate any opinions that are out there. I'm worried sick that the engine is done for and I'll be on the hook to replace it. That's what the tow truck operator suggested.
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Old 09-02-12, 06:30 AM   #32
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Quote:
Originally Posted by jrein View Post
After studying the DIY for changing out knock sensors, I felt it was a bit out of my league so I took it to a local shop to get the job done. They charged $1100 to do it, including an oil change. My wife picked up the car, got three miles from the shop and heard a bang from the engine compartment. There's now a loud metal-to-metal clicking from inside the engine. It can hardly idle. I fear a broken connecting rod. I had the car towed back, but the shop is closed for the holiday weekend. Do you think my engine problem is a result of an error by the mechanic? Any thoughts on things that could go wrong in a knock sensor replacement that could lead to what seems to be a serious engine malfunction? I'd appreciate any opinions that are out there. I'm worried sick that the engine is done for and I'll be on the hook to replace it. That's what the tow truck operator suggested.
Welcome to Club Lexus!

Did you check the oil level?
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Old 09-02-12, 07:41 AM   #33
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Quote:
Originally Posted by jrein View Post
After studying the DIY for changing out knock sensors, I felt it was a bit out of my league so I took it to a local shop to get the job done. They charged $1100 to do it, including an oil change. My wife picked up the car, got three miles from the shop and heard a bang from the engine compartment. There's now a loud metal-to-metal clicking from inside the engine. It can hardly idle. I fear a broken connecting rod. I had the car towed back, but the shop is closed for the holiday weekend. Do you think my engine problem is a result of an error by the mechanic? Any thoughts on things that could go wrong in a knock sensor replacement that could lead to what seems to be a serious engine malfunction? I'd appreciate any opinions that are out there. I'm worried sick that the engine is done for and I'll be on the hook to replace it. That's what the tow truck operator suggested.
Sorry to hear this, but you are letting your mind run a bit out of control here. Recent events are very important but you must logically start by what is wrong and then look at the possibilities.

Hyper pointed out start by checking oil.

The knock sensor change process is a bit involved, but it is unlikely to cause a serious failure except something falling in the air-intake. Every thing else is just sensors, vacuum , fuel and air delivery. I would expect to get a CEL and worse engine refusing to run. Leaks as a result of not replacing a gasket or not torquing the components down properly would be the other problem.

Keep in mind that we are dealing with machines and a totally unrelated failure can happen and unethical shops have fleeced customers by weakening some other component(s) to create more business. [Sorry for adding fuel to the fire]

Salim
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Old 09-02-12, 09:51 AM   #34
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Thanks for the response guys.

The oil level was fine. The coolant resevoir was slightly below the low level. Odd, since the paperwork from the shop indicated they topped off all the fluids. I opened up the radiator cap when it cooled and found fluid near the top. My wife, who was driving at the time, said the engine temp was normal and did not see a check engine light. The car has about 64K miles.

I know that there's a possibility that my engine troubles aren't related to the recent work, but given the timing and the relatively low mileage, I have to question it.
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Old 09-02-12, 12:33 PM   #35
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Knock sensor replacement requires draining coolant and it needs to e filled at the end. Usually a day or two of driving gets some of the air trapped in the system. Adding upto 1/2 cup of distilled water is quite normal.

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Old 09-10-12, 01:09 AM   #36
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Welcome to Club Lexus!

Did you check the oil level?
it could be a wrench sitting on the top of the engine and fall at the pulley or where the the moving parts after 3 miles from the shop ....
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Old 09-10-12, 09:56 AM   #37
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Any update jrein?
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Old 09-10-12, 10:39 AM   #38
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The shop (Japanese Automotive Service Professionals of Apharetta GA) repaired the car at no cost. They went so far as to offer to cover the towing expense. Clearly a stand-up operation.

They said the issue was with the intake baffle. I was pressed for time when I picked the car up, so I didn't get the full details.
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Old 09-10-12, 02:55 PM   #39
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I keep reminding folks that the cost of repairs has to have a margin for things that can go bad and once in a while they do go bad.

Glad that they took care of you.

Salim
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Old 11-19-12, 08:16 AM   #40
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RX300 knock sensor replacement DIY

Salim,

Appreciate the post. I did quite a bit of research before cracking the hood open and always went back to your instructions as my master guide. Busted knuckles and 8 hours later, the RX is running great again.

Thanks again, Richard
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Old 02-23-13, 12:23 PM   #41
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Great write-up, as usual. Question: Would most of these steps be necessary in order to replace the rear valve cover gasket? (I don't see a sticky for that job.) And, if I'm going to go to all this trouble in order to replace just valve cover gaskets, should I replace the knock sensors also, even though not bad? Mileage 210K. TIA.
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Old 02-23-13, 02:11 PM   #42
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In y our parts list you say 'wire harness - probably can not reuse existing' or words to that effect. Which harness are you talking about?
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Old 02-23-13, 02:19 PM   #43
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Great information. This will be very handy!
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Old 02-23-13, 02:57 PM   #44
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There is only one harness ... connects to the knock-sensor to the main harness.

The connectors get hot and over time they disintegrate. In my case, I was hesitant to pre-order them but decided to purchase it and it was the right decision.

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Old 02-23-13, 03:05 PM   #45
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Quote:
Originally Posted by JAB View Post
Great write-up, as usual. Question: Would most of these steps be necessary in order to replace the rear valve cover gasket? (I don't see a sticky for that job.) And, if I'm going to go to all this trouble in order to replace just valve cover gaskets, should I replace the knock sensors also, even though not bad? Mileage 210K. TIA.
To get to the knock sensor, you have to take the air intake off.

To get to the rear-valve cover, you have to take the air intake off.

Salim
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Old 02-23-13, 03:05 PM
 
 
 
 
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1999, arm, break, clean, cleaner, engine, fuel, knock, lexus, location, replace, rx300, sensor, sensors, shaking, wiper

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