Possible rod knock - Toyota GR86, 86, FR-S and Subaru BRZ Forum & Owners Community

molassascookieman · 03-07-2019, 05:35 PM

Story time. I have a 13 FR-S with 140,000 on the engine to date. About a month and a half ago, I raced a Jaguar at around 120 for a good 3 solid hours down I-10, and when I finally slowed down, I heard a weird, throaty rattle coming from the engine. At first I thought it was related to the clutch, as it stopped when I was in neutral with my foot off the clutch. I then took my car into Toyota to have the valve-spring recall done, and got a call saying my engine has a rod knock, it has nothing to do with the clutch, and my engine needs replacing.

Now I trust this dealership, and have no reason to believe they are trying to hustle me (they know full well I know a lot more about cars than the average person, and have even told me to go away and do it myself when I brought it in for some other stuff). BUT, I am skeptical of their diagnosis, because I have heard many rod knocks before, even from other BRZs, and this sounds way less violent, is coming from the bottom of the engine not the top, and because the sound gets louder when I accelerate. I can't really get a good audio clip or video clip because the short shifter starts rattling whenever I'm going fast enough to hear it.

The sound is a deeper rattle, almost sounds like somebody gargling water, but more mechanical. It has gotten somewhat worse since it started, and it does get slightly worse when the engine warms up, but everything else points to it not being a rod knock. Any idea what else this might be, and any fixes I could attempt?

Subsonic · 03-07-2019, 05:49 PM

There are literally a million things it can be, so a diagnosis over the internet is going to be difficult. You could get a second opinion from another mechanic, or do an oil sample analysis which should show up bearing material in the oil if there is indeed a rod bearing issue.

Ultramaroon · 03-07-2019, 05:58 PM

If it's rod knock you'd hear it just as well racing the engine in neutral. Take a recording of that outside so we don't hear echo from the garage. Make sure the oil is up to temp.

James H · 03-07-2019, 06:29 PM

Jaguar? I take it not a late model S Type with the supercharged V8

maslin · 03-07-2019, 06:51 PM

Quote:

Originally Posted by molassascookieman

Story time. I have a 13 FR-S with 140,000 on the engine to date. About a month and a half ago, I raced a Jaguar at around 120 for a good 3 solid hours down I-10, and when I finally slowed down, I heard a weird, throaty rattle coming from the engine. At first I thought it was related to the clutch, as it stopped when I was in neutral with my foot off the clutch. I then took my car into Toyota to have the valve-spring recall done, and got a call saying my engine has a rod knock, it has nothing to do with the clutch, and my engine needs replacing.

Now I trust this dealership, and have no reason to believe they are trying to hustle me (they know full well I know a lot more about cars than the average person, and have even told me to go away and do it myself when I brought it in for some other stuff). BUT, I am skeptical of their diagnosis, because I have heard many rod knocks before, even from other BRZs, and this sounds way less violent, is coming from the bottom of the engine not the top, and because the sound gets louder when I accelerate. I can't really get a good audio clip or video clip because the short shifter starts rattling whenever I'm going fast enough to hear it.

The sound is a deeper rattle, almost sounds like somebody gargling water, but more mechanical. It has gotten somewhat worse since it started, and it does get slightly worse when the engine warms up, but everything else points to it not being a rod knock. Any idea what else this might be, and any fixes I could attempt?

A rod knock is from the bottom end, not the top. They get much louder under load. A rod knock is a nice deep thunk thunk thunk, they don't always sound very metallic, and they usually sound "wet".

Basically, it sounds like you have a rod knock. But this is the internet. So it could really be anything.

DarkPira7e · 03-07-2019, 08:19 PM

this was my rod knock. Spun #4 rod bearing

ermax · 03-07-2019, 08:34 PM

Quote:

Originally Posted by DarkPira7e

this was my rod knock. Spun #4 rod bearing

That’s not rod knock. That is just your flasher relay.

I kid I kid.

ermax · 03-07-2019, 08:43 PM

If it was rod knock you wouldn’t have a hard time reproducing it or hearing it. My car has had a faint rod knock like sound from the day I got the car. It’s a 2013 I picked up used with 83k. I did end up spinning a bearing and I replaced the short block but what do you know it still has this damn rod knock like sound when under light load at about 2500rpm. I’ve finally gotten used to the sound so it doesn’t trigged butterflies in my stomach anymore.

03-07-2019, 05:35 PM	#1
molassascookieman Junior Member Join Date: Jan 2019 Drives: 2013 FR-S Manual (Stock for now) Location: San Antonio Posts: 1 Thanks: 0 Thanked 0 Times in 0 Posts Mentioned: 0 Post(s) Tagged: 0 Thread(s)	Possible rod knock Story time. I have a 13 FR-S with 140,000 on the engine to date. About a month and a half ago, I raced a Jaguar at around 120 for a good 3 solid hours down I-10, and when I finally slowed down, I heard a weird, throaty rattle coming from the engine. At first I thought it was related to the clutch, as it stopped when I was in neutral with my foot off the clutch. I then took my car into Toyota to have the valve-spring recall done, and got a call saying my engine has a rod knock, it has nothing to do with the clutch, and my engine needs replacing. Now I trust this dealership, and have no reason to believe they are trying to hustle me (they know full well I know a lot more about cars than the average person, and have even told me to go away and do it myself when I brought it in for some other stuff). BUT, I am skeptical of their diagnosis, because I have heard many rod knocks before, even from other BRZs, and this sounds way less violent, is coming from the bottom of the engine not the top, and because the sound gets louder when I accelerate. I can't really get a good audio clip or video clip because the short shifter starts rattling whenever I'm going fast enough to hear it. The sound is a deeper rattle, almost sounds like somebody gargling water, but more mechanical. It has gotten somewhat worse since it started, and it does get slightly worse when the engine warms up, but everything else points to it not being a rod knock. Any idea what else this might be, and any fixes I could attempt?

03-07-2019, 05:58 PM	#3
Ultramaroon 義理チョコ Join Date: Sep 2014 Drives: a 13 e8h frs Location: vantucky, wa Posts: 31,870 Thanks: 52,132 Thanked 36,521 Times in 18,922 Posts Mentioned: 1107 Post(s) Tagged: 9 Thread(s)	If it's rod knock you'd hear it just as well racing the engine in neutral. Take a recording of that outside so we don't hear echo from the garage. Make sure the oil is up to temp. __________________ service manuals

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Knock Knock? Expired Warranty	Frivo	Issues \| Warranty \| Recalls / TSB	20	08-17-2020 09:04 PM
Tip in knock	Tor	Software Tuning	32	03-22-2018 12:13 PM
Knock Correction vs Knock Correction Learn values?	swift996	Software Tuning	19	11-03-2015 10:09 PM
FR-S Rod knock	pozer	Issues \| Warranty \| Recalls / TSB	95	11-03-2015 09:39 AM
Oft knock	brady86	Software Tuning	26	07-15-2015 10:14 PM

03-07-2019, 05:49 PM	#2
Subsonic Member Join Date: Dec 2016 Drives: Toyota 86 GTS Location: Sydney Australia Posts: 76 Thanks: 77 Thanked 114 Times in 36 Posts Mentioned: 3 Post(s) Tagged: 0 Thread(s)	There are literally a million things it can be, so a diagnosis over the internet is going to be difficult. You could get a second opinion from another mechanic, or do an oil sample analysis which should show up bearing material in the oil if there is indeed a rod bearing issue.

03-07-2019, 06:29 PM	#4
James H Senior Member Join Date: Mar 2019 Drives: 2017 BRZ Location: Newmarket Posts: 153 Thanks: 14 Thanked 127 Times in 66 Posts Mentioned: 0 Post(s) Tagged: 0 Thread(s)	Jaguar? I take it not a late model S Type with the supercharged V8

03-07-2019, 08:19 PM	#6
DarkPira7e Rust bucket enthusiast Join Date: Feb 2017 Drives: 2013 Turbo Firestorm FRS Location: Vermont Posts: 3,934 Thanks: 3,200 Thanked 4,095 Times in 2,045 Posts Mentioned: 31 Post(s) Tagged: 0 Thread(s)	this was my rod knock. Spun #4 rod bearing

03-07-2019, 08:43 PM	#8
ermax Senior Member Join Date: Sep 2017 Drives: 2022 BRZ Limited Silver Location: Jacksonville, FL Posts: 2,532 Thanks: 882 Thanked 2,045 Times in 1,188 Posts Mentioned: 68 Post(s) Tagged: 0 Thread(s)	If it was rod knock you wouldn’t have a hard time reproducing it or hearing it. My car has had a faint rod knock like sound from the day I got the car. It’s a 2013 I picked up used with 83k. I did end up spinning a bearing and I replaced the short block but what do you know it still has this damn rod knock like sound when under light load at about 2500rpm. I’ve finally gotten used to the sound so it doesn’t trigged butterflies in my stomach anymore.

User Name		Remember Me?
Password