Solving the Valve Cover Gaskets - Permanently
12-02-05, 10:49 PM
#1
Lexus Champion
Thread Starter
Solving the Valve Cover Gaskets - Permanently
This is a "your thoughts" thread.
(For the remainder of the thread VCG - Valve Cover Gasket. RVCG - Specifying the REAR Valve Cover Gasket, FVCG - You are a moron if you need this definition)
It's obvious Toyota's implementation for the v6's doesn't work. Blame whatever you want, but there is no arguing the fact that it simply does not work. Worse, nearly every engine has a VCG leaking to some extinct, almost EVER engine will have the RVCG leaking over time.
IMHO it's from a culmination of two things:
1) I don't like the groove style VCG. The flat engine's use corker, rubber"ish", or rubber/steel core gaskets & have less problems. Not only that, but it is advantageous in that if it is ever replaced (for any reason) you simply use a tube of gasket maker & the seal is nearly indefinite. When applied correctly, they won't leak until you break the seal!
2) Improper valve cover gasket bolt torque. Even tho the rubber gasket provides some tension on the cylinder head bolts, the spec is 4.3-5.75ft-lb. They easily get loose, or are extremely over tightened when repaired.
3) 1 & 2 are compounded by the huge rearward angle the v6's are tilted at.
So I'm sick of it. Sick of hearing about it. Sick of most of us considering it a "routine maintenance" item that should be replaced every time someone is going near them. "Oh well you're getting X done, Have them do the VCG's before they start to leak!" etc.
Here's how I think we deal with it once & solve it for the last damn time.
Supply list:
Ultra Black RTV. RTV is *the* gasket "brand" of choice by everyone. Ultra Black is a premium line, and Permatex's most oil resistant RTV gasket. Even better. It is apply & go. (Non-premium RTV's need time to setup when mounted & some need to be re-torqued.) It could take 2 tubes. I used 1.
Thread Locker (Medium - Loc-tite & Permatex Blue)
M7-1 Tap
Acetone, Paper towels, Q-tips. (Ya, ya Alcohol works, Acetone just eats oil so much faster tho! Ventilated area for both)
Scraper (or something with a flat edge you can level with)
1) Clean the gasket mating surfaces with Acetone. I find you can push paper towels through the groove, but a few Q-tips make very short work of it & you can be sure you've cleaned it thoroughly.
2) Completely fill the groove with RTV & scrape it flat so that it's a flush surface.
3) Run your tap down the threads of the valve cover bolt holes. This will clean the threads up.
4) (After the RTV has cured - 24 hours) Apply your "normal" 1/4" bead of RTV as a normal application.
5) (IMMEDIATELY) Put valve cover on & bolt it down. Since we're no longer using a "light pressure to seal" gasket. Torque the valve covers down to say 18-20ft-lb.
Using online calculators: The stock bolt & hole threads have a Recommended Torque of 15.2 ft-lb & Maximum Torque of 20.2 ft-lb (Not freaking 4-5ft-lb!?)
I don't think it would be wise to drill & tap for a larger size, tho someone could. It'd be hard to drill large enough to have good threads, without having some huge bolt running down it. (I just don't think there is any reason for like an M10. Those would hold 40-50ft-lb! That's above the head gasket range!)
Anywho... That's what I did.
(For the remainder of the thread VCG - Valve Cover Gasket. RVCG - Specifying the REAR Valve Cover Gasket, FVCG - You are a moron if you need this definition)
It's obvious Toyota's implementation for the v6's doesn't work. Blame whatever you want, but there is no arguing the fact that it simply does not work. Worse, nearly every engine has a VCG leaking to some extinct, almost EVER engine will have the RVCG leaking over time.
IMHO it's from a culmination of two things:
1) I don't like the groove style VCG. The flat engine's use corker, rubber"ish", or rubber/steel core gaskets & have less problems. Not only that, but it is advantageous in that if it is ever replaced (for any reason) you simply use a tube of gasket maker & the seal is nearly indefinite. When applied correctly, they won't leak until you break the seal!
2) Improper valve cover gasket bolt torque. Even tho the rubber gasket provides some tension on the cylinder head bolts, the spec is 4.3-5.75ft-lb. They easily get loose, or are extremely over tightened when repaired.
3) 1 & 2 are compounded by the huge rearward angle the v6's are tilted at.
So I'm sick of it. Sick of hearing about it. Sick of most of us considering it a "routine maintenance" item that should be replaced every time someone is going near them. "Oh well you're getting X done, Have them do the VCG's before they start to leak!" etc.
Here's how I think we deal with it once & solve it for the last damn time.
Supply list:
Ultra Black RTV. RTV is *the* gasket "brand" of choice by everyone. Ultra Black is a premium line, and Permatex's most oil resistant RTV gasket. Even better. It is apply & go. (Non-premium RTV's need time to setup when mounted & some need to be re-torqued.) It could take 2 tubes. I used 1.
Thread Locker (Medium - Loc-tite & Permatex Blue)
M7-1 Tap
Acetone, Paper towels, Q-tips. (Ya, ya Alcohol works, Acetone just eats oil so much faster tho! Ventilated area for both)
Scraper (or something with a flat edge you can level with)
1) Clean the gasket mating surfaces with Acetone. I find you can push paper towels through the groove, but a few Q-tips make very short work of it & you can be sure you've cleaned it thoroughly.
2) Completely fill the groove with RTV & scrape it flat so that it's a flush surface.
3) Run your tap down the threads of the valve cover bolt holes. This will clean the threads up.
4) (After the RTV has cured - 24 hours) Apply your "normal" 1/4" bead of RTV as a normal application.
5) (IMMEDIATELY) Put valve cover on & bolt it down. Since we're no longer using a "light pressure to seal" gasket. Torque the valve covers down to say 18-20ft-lb.
Using online calculators: The stock bolt & hole threads have a Recommended Torque of 15.2 ft-lb & Maximum Torque of 20.2 ft-lb (Not freaking 4-5ft-lb!?)
I don't think it would be wise to drill & tap for a larger size, tho someone could. It'd be hard to drill large enough to have good threads, without having some huge bolt running down it. (I just don't think there is any reason for like an M10. Those would hold 40-50ft-lb! That's above the head gasket range!)
Anywho... That's what I did.
12-03-05, 12:08 AM
#2
Lexus Champion
Thread Starter
If someone had some money, you could also JB Weld the groove full. JB Weld is awesome on Aluminum. They expand at virtually the same rate @ the same temperature.
Or just weld it full...
Or just weld it full...
10-23-08, 09:51 AM
#5
WOW!!! I just finished these extensively intense job!! 95 es300. WHEW!!!
I tried the RTV-only method and failed. It absolutely did not work for me. LOL! I finished the project, put everything together and started it up. I let it run for a bit. The driveway looked like Smokey's BBQ grill. There was oil leaking directly out of the back of the RVC onto the exhaust. It was worse than the small, unnoticeable, just annoying leak that I was trying to solve!!!
Anyway, had to pull it off again. Cleaned all of the RTV out of the RVC. Bought the factory gasket from the stealership. Installed with RTV between the gasket and the mounting surface on the engine. Waited an hour (about the time it took me to reassemble the rest of the engine, give or take 15 min). Started it up. No problems!!! Wow!! What a job. I have to admit. It's a horrible design for toyota/lexus to release, but it has to serve some purpose though I haven't figured it out yet... Just my experience.
I tried the RTV-only method and failed. It absolutely did not work for me. LOL! I finished the project, put everything together and started it up. I let it run for a bit. The driveway looked like Smokey's BBQ grill. There was oil leaking directly out of the back of the RVC onto the exhaust. It was worse than the small, unnoticeable, just annoying leak that I was trying to solve!!!
Anyway, had to pull it off again. Cleaned all of the RTV out of the RVC. Bought the factory gasket from the stealership. Installed with RTV between the gasket and the mounting surface on the engine. Waited an hour (about the time it took me to reassemble the rest of the engine, give or take 15 min). Started it up. No problems!!! Wow!! What a job. I have to admit. It's a horrible design for toyota/lexus to release, but it has to serve some purpose though I haven't figured it out yet... Just my experience.
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