Exhaust Valve Stem Seals Leaking Oil - Toyota GR86, 86, FR-S and Subaru BRZ Forum & Owners Community

kimcheefists · 03-06-2019, 07:06 PM

Hi everyone,

Like the title states, the #3 cylinder (passenger side rear) exhaust valve stem seals allowed oil to leak into my exhaust system creating a ton of smoke when the car was under load and accelerating from a stop.

At the time the problem began, mods included a JDL turbo kit, Verus AOS, and a JDL oil cooler.

I was speaking in past tense because my engine is now getting built with forged bottom end components and Supertech valve springs since the engine needed to be removed in order to fix the valve stem seal leak anyway. I’m also changing the AOS to Radium’s dual catch can.

The reason for this post is because the mechanic that’s doing the engine work stated that he believes it’s a common issue with the FA20 motors. He said that a WRX came into his shop with the same issue...

Has anyone else had this problem? This rebuild has obviously taken a hit to my wallet and a little worried that the problem will surface again in the future..Any responses are greatly appreciated!

humfrz · 03-07-2019, 01:23 AM

I haven't read anything on this forum about bad valve stem seals. -

humfrz

kimcheefists · 03-07-2019, 05:44 AM

Yeah I haven’t seen anything either but wanted to throw the question out to the community anyway...

Does anyone know what usually causes valve stem seals to go bad in the first place?

Sent from my iPhone using Tapatalk

Muaddib · 03-07-2019, 11:08 AM

Usually with high mileage 5SFE had that issue. Certainly not a very common problem with toyota engines.

ka-t_240 · 03-07-2019, 11:24 AM

Quote:

Originally Posted by Muaddib

Usually with high mileage 5SFE had that issue. Certainly not a very common problem with toyota engines.

You mean Subaru engines.

anjob21 · 11-11-2024, 02:57 AM

Quote:

Originally Posted by kimcheefists

Hi everyone,

Like the title states, the #3 cylinder (passenger side rear) exhaust valve stem seals allowed oil to leak into my exhaust system creating a ton of smoke when the car was under load and accelerating from a stop.

At the time the problem began, mods included a JDL turbo kit, Verus AOS, and a JDL oil cooler.

I was speaking in past tense because my engine is now getting built with forged bottom end components and Supertech valve springs since the engine needed to be removed in order to fix the valve stem seal leak anyway. IÂ’m also changing the AOS to RadiumÂ’s dual catch can.

The reason for this post is because the mechanic thatÂ’s doing the engine work stated that he believes itÂ’s a common issue with the FA20 motors. He said that a WRX came into his shop with the same issue...

Has anyone else had this problem? This rebuild has obviously taken a hit to my wallet and a little worried that the problem will surface again in the future..Any responses are greatly appreciated!

I am having the same issue where my cyl 3 plug gets fouled by a lot of carbon build up. I am boosted. Burns oil when under load.

Tokay444 · 11-11-2024, 04:41 PM

I'd look at rings before valve stem seals on this engine. Especially boosted.

NoHaveMSG · 11-11-2024, 07:19 PM

Exhaust valve stem seals leak under vacuum. Need a leak down done.

Tokay444 · 11-12-2024, 10:16 AM

Exactly. Boost would be pushing back into the head under load.

Opie · 11-12-2024, 11:51 AM

I'll bet the #3 piston ring land is cracked....and it's not a spring issue....

NoHaveMSG · 11-13-2024, 03:46 PM

I wouldn’t rule out something simple like a bad PCV yet, but fouling number 3 all the time is not promising.

Comp test
Leak down test.

Everything else until then is just guessing.

Muskoka800 · 11-16-2024, 10:49 AM

Outfront Motorsports suggested including new valve guides when I was shopping for a built short block. They stated the guides are often troublesome eventually.

03-06-2019, 07:06 PM	#1
kimcheefists Member Join Date: Mar 2015 Drives: 2017 BRZ PP Location: Las Vegas Posts: 40 Thanks: 5 Thanked 9 Times in 8 Posts Mentioned: 1 Post(s) Tagged: 0 Thread(s)	Exhaust Valve Stem Seals Leaking Oil Hi everyone, Like the title states, the #3 cylinder (passenger side rear) exhaust valve stem seals allowed oil to leak into my exhaust system creating a ton of smoke when the car was under load and accelerating from a stop. At the time the problem began, mods included a JDL turbo kit, Verus AOS, and a JDL oil cooler. I was speaking in past tense because my engine is now getting built with forged bottom end components and Supertech valve springs since the engine needed to be removed in order to fix the valve stem seal leak anyway. I’m also changing the AOS to Radium’s dual catch can. The reason for this post is because the mechanic that’s doing the engine work stated that he believes it’s a common issue with the FA20 motors. He said that a WRX came into his shop with the same issue... Has anyone else had this problem? This rebuild has obviously taken a hit to my wallet and a little worried that the problem will surface again in the future..Any responses are greatly appreciated!

11-16-2024, 10:49 AM	#12
Muskoka800 Senior Member Join Date: Jul 2018 Drives: 2016 Scion FRS Release Series 2#439 Location: Chatham, Ontario, Canada Posts: 729 Thanks: 4 Thanked 158 Times in 131 Posts Mentioned: 4 Post(s) Tagged: 0 Thread(s)	Outfront Motorsports suggested including new valve guides when I was shopping for a built short block. They stated the guides are often troublesome eventually. __________________ Edelbrock S/C with CSG 94 & 91 maps TRD Short Shifter, CTS/EvoX Brakes Ohlin’s R&T Dampers, Hotchkis F/R Bars, Blox LCA & Toe Arms 235F/245R Conti ECS on TRD/Enkei wheels (street), 245/40 sq. ECF on 17x8 720Form GTF2 wheels (track)

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03-07-2019, 01:23 AM	#2
humfrz Senior Member Join Date: May 2013 Drives: 2013 FR-S, white, MT Location: Puyallup, WA Posts: 30,140 Thanks: 29,277 Thanked 32,300 Times in 16,621 Posts Mentioned: 709 Post(s) Tagged: 2 Thread(s)	I haven't read anything on this forum about bad valve stem seals. - humfrz

03-07-2019, 05:44 AM	#3
kimcheefists Member Join Date: Mar 2015 Drives: 2017 BRZ PP Location: Las Vegas Posts: 40 Thanks: 5 Thanked 9 Times in 8 Posts Mentioned: 1 Post(s) Tagged: 0 Thread(s)	Exhaust Valve Stem Seals Leaking Oil Yeah I haven’t seen anything either but wanted to throw the question out to the community anyway... Does anyone know what usually causes valve stem seals to go bad in the first place? Sent from my iPhone using Tapatalk Last edited by kimcheefists; 03-07-2019 at 06:07 AM.

03-07-2019, 11:08 AM	#4
Muaddib Mentat Join Date: Jun 2013 Drives: 2013 Scion FRS 6MT Location: Vancouver Posts: 542 Thanks: 666 Thanked 358 Times in 198 Posts Mentioned: 4 Post(s) Tagged: 0 Thread(s)	Usually with high mileage 5SFE had that issue. Certainly not a very common problem with toyota engines.

11-11-2024, 04:41 PM	#7
Tokay444 Anti stance. Join Date: Feb 2016 Drives: 17 White 860. RCE Tarmac 2. RE-71RS Location: Not Canada Posts: 1,698 Thanks: 918 Thanked 991 Times in 567 Posts Mentioned: 10 Post(s) Tagged: 0 Thread(s)	I'd look at rings before valve stem seals on this engine. Especially boosted.

11-12-2024, 10:16 AM	#9
Tokay444 Anti stance. Join Date: Feb 2016 Drives: 17 White 860. RCE Tarmac 2. RE-71RS Location: Not Canada Posts: 1,698 Thanks: 918 Thanked 991 Times in 567 Posts Mentioned: 10 Post(s) Tagged: 0 Thread(s)	Exactly. Boost would be pushing back into the head under load.

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