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#1 |
Post Whore
![]() Join Date: Feb 2016
Location: Portland Oregon
Posts: 11,110
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Why RTV sealant is bad!
I pulled this engine apart yesterday and found this. From the outside I noticed the blue goo oozing from every joint around the timing cover. Photos 1 and 2. Photo #2 has blue lines pointing to the over application of RTV. When I pulled the head photo 3 shows the RTV that was inside of the water passage. The 4th photo shows the total length of the RTV that was in the passage. It is obvious that there was little to no water flow to number one cylinder.
RTV sealant must be use with discretion. Too much can be damaging. The is a reason that manufacturers like CAT no longer use RTV sealants. They now use the more expensive Anaerobic type sealants to prevent to prevent this kind of problem.
__________________
Thanks to Bob and Jeanie and everyone else at Superior Performance for all their great help. ![]() RIP Bob Parks. 1967 Burban (the WMB),1988 S10 Blazer (the Stink10 II),1969 GTO (the Goat), 1970 Javelin, 1952 F2 Ford OHC six 4X4, 29 Model A, 72 Firebird (the DBP Bird). 85 Alfa Romeo If it breaks I didn't want it in the first place The WMB repair thread http://67-72chevytrucks.com/vboard/s...d.php?t=698377 |
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#2 |
Special Order
![]() ![]() Join Date: Nov 2004
Location: Mt Airy, MD
Posts: 85,859
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Re: Why RTV sealant is bad!
I think the problem is 'misusing' RTV, not using. Too heavy an application I have known to be bad for many years. It's a good thing when used right. I never used it all that much, but it has it's good uses.
__________________
"BUILDING A BETTER WAY TO SERVE THE USA"......67/72......"The New Breed" GMC '67 C1500 Wideside Super Custom SWB: 327/M22/3.42 posi.........."The '67" (project) GMC '72 K2500 Wideside Sierra Custom Camper: 350/TH350/4.10 Power-Lok..."The '72" (rolling) Tim "Don't call me a redneck. I'm a rough cut country gentleman" R.I.P. ~ East Side Low Life ~ El Jay ~ 72BLUZ ~ Fasteddie69 ~ Ron586 ~ 67ChevyRedneck ~ Grumpy Old Man ~ |
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#3 |
Senior Member
![]() Join Date: Nov 2018
Location: Waterford California
Posts: 2,517
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Re: Why RTV sealant is bad!
I guess I'm still old fashion as I still use gaskets with a very light film of RTV to fill any voids.
A few years back before the internet I went to a parts house for a couple of front/rear differential gaskets for my 46 CJ2A, I was told #1 "we don't have those" and #2 "everyone just uses silicone"....not me, I eventually got my gaskets. |
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#4 |
Senior Member
![]() Join Date: Jan 2001
Location: Orem, Utah
Posts: 7,903
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Re: Why RTV sealant is bad!
I only use RTV where necessary. I prefer to use gaskets with a light coating of Permatex Aviation Form-A-Gasket on both surfaces.
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I have sworn upon the altar of God, eternal hostility against every form of tyranny over the mind of man. - Thomas Jefferson |
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#5 |
Registered User
Join Date: Jan 2016
Location: Barber City, CA
Posts: 4,778
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Re: Why RTV sealant is bad!
there isn't a sbc on the planet that won't leak somewhere without rtv
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I started out with nothing - and I still have most of it |
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#6 |
Registered User
Join Date: Nov 2016
Location: Vancouver BC
Posts: 162
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Re: Why RTV sealant is bad!
Don't blame the gun - blame the gunner. RTV in the appropriate amount is ok
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#7 |
Registered User
Join Date: Jul 2008
Location: Bowie, MD
Posts: 313
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Re: Why RTV sealant is bad!
Hogwash! I love it so much I use Ultra Copper as toothpaste!
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#8 | |
Who Changed This?
![]() Join Date: Jan 2013
Location: Simi Valley, CA
Posts: 10,388
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Re: Why RTV sealant is bad!
Quote:
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~Steven '70 Chevy 3/4T Longhorn CST 402/400/3.56 Custom Camper Simi Valley, CA |
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#9 | |
Special Order
![]() ![]() Join Date: Nov 2004
Location: Mt Airy, MD
Posts: 85,859
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Re: Why RTV sealant is bad!
Quote:
I get what HO455 is saying about excess RTV "internal ooze". Button the thing up and that's the part you don't see and it can cause some serious issues. This is why RTV "can be" bad
__________________
"BUILDING A BETTER WAY TO SERVE THE USA"......67/72......"The New Breed" GMC '67 C1500 Wideside Super Custom SWB: 327/M22/3.42 posi.........."The '67" (project) GMC '72 K2500 Wideside Sierra Custom Camper: 350/TH350/4.10 Power-Lok..."The '72" (rolling) Tim "Don't call me a redneck. I'm a rough cut country gentleman" R.I.P. ~ East Side Low Life ~ El Jay ~ 72BLUZ ~ Fasteddie69 ~ Ron586 ~ 67ChevyRedneck ~ Grumpy Old Man ~ |
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#10 |
Who Changed This?
![]() Join Date: Jan 2013
Location: Simi Valley, CA
Posts: 10,388
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Re: Why RTV sealant is bad!
I remember an old story (I think in Hot Rod Magazine) about some team losing a drag race because the carb had a chunk of RTV in it. I don't let stuff like that get anywhere near the fuel system. I wonder how that happened?
__________________
~Steven '70 Chevy 3/4T Longhorn CST 402/400/3.56 Custom Camper Simi Valley, CA |
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#11 |
Registered User
Join Date: Apr 2009
Location: PNW
Posts: 553
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Re: Why RTV sealant is bad!
NOTHING wrong with RTV.
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#12 | |
Senior Member
![]() Join Date: Nov 2018
Location: Waterford California
Posts: 2,517
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Re: Why RTV sealant is bad!
Quote:
Got it up and running and had problems right away, pulled the front bowl off and it was full of RTV bits, of course plugging the jets and whatever else. I thought how in the sam hell did that get in the fuel system. It appeared that the carb had not been separated and no sign of RTV on the bowl gaskets. Got a gasket kit cleaned it all out still runs perfect today. One of those mystery's. |
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#13 | |
Registered User
Join Date: Feb 2011
Location: Under the Truck Dreaming
Posts: 702
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Re: Why RTV sealant is bad!
Quote:
HO455 please tell us about the newest Anaerobic sealants. Product names part numbers where we can get it...
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72 K20 Custom Camper, D60, 14BFF, full roller 406 TPI w custom built ECU and yes..it has tow hooks... |
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#14 |
Registered User
Join Date: Oct 2016
Location: Dallas Texas
Posts: 3,081
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Re: Why RTV sealant is bad!
.
Gaskets + Gasgacinch! -klb
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67 C10 fleet fuel injected '70 402, 700r4, 3.73 posi 07 335 sport turbo 6sp 94 Trans Am GT LT1 6sp posi -- sold after 22yrs 99 540 sport V8 6sp -- sold 73 240z L24 4sp -- given to friend 68 C10 step 350/350 3.73 open -- sold Last edited by weq92f; 10-07-2020 at 06:20 PM. |
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#15 | |
Registered User
Join Date: Jan 2016
Location: Barber City, CA
Posts: 4,778
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Re: Why RTV sealant is bad!
Quote:
the proper use of each is the path to success ![]() THE TEN MOST COMMON GASKETING MISTAKES 6. Trying to fill a large gap with an anaerobic gasket maker. Anaerobic gasket makers and flange sealants are designed for sealing assemblies where two close fitting machined metal surfaces come together. They’re generally recommended for gaps of up to 15 to 20 thousandths of an inch only. If you’ve got larger gaps – such as sealing a stamped steel oil pan, you should be using an RTV gasket maker. what you may not understand is that anaerobic sealants will stand in open containers for years and never cure until applied where isolated from oxygen.. loctite thread lockers are a perfect example of this, they'll sit without caps for years and still be liquid.. rtv products work much differently, they react to the moisture in the air which initiates curing process.. they are also a type of anaerobic as they continue to cure internally where oxygen is not present.. that is why a slightly used tube of rtv will be cured to the seam with a year or two after opening.. there are hundreds of these types of products out there.. best practice is to become more familiar with the process you're working with and apply the proper sealing technique and sealants to the job.. happy sealing! ![]()
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I started out with nothing - and I still have most of it |
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#16 |
laying low
![]() Join Date: Mar 2001
Location: Searcy, Ark. USA
Posts: 13,221
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Re: Why RTV sealant is bad!
Way back in the 80s the company mechanic ( and I use that term oh so generously ) kept the trucks running, in and out of the shop mostly.
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Boog 69 Chevy stepside, 358/T350, 4.11 posi, 4.5/4 drop, rallys, poboy driver primer is finer 91 Chevy sportside, Tahoe, Yukon & GMC Crewcab All GM..'nuff said. I stand for the flag and kneel at the cross |
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#17 |
Registered User
Join Date: May 2016
Location: Henderson NC
Posts: 975
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Re: Why RTV sealant is bad!
If you use the right stuff in the right places there is nothing wrong with it. Just rebuilt a Toyota 22re and the pan gasket is still laying on the workbench. The gasket will leak long before the FIPG gasket maker will. Lots of auto manufacturers recommend gasket makers in a tube over regular gaskets nowadays.
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#18 | |
Registered User
Join Date: Jul 2018
Location: Catskill Mountains,NY
Posts: 8,469
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Re: Why RTV sealant is bad!
Quote:
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Mark 72 c20 custom camper Husky edition, 66 SS396 Chevelle 1964 Hawk, 63 Avanti,62 lark 1969 AMX , 1968 c20 stepside ,85 K20 1977 Suburban sold 68 anniversary. |
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#19 | |
Registered User
Join Date: Jan 2016
Location: Barber City, CA
Posts: 4,778
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Re: Why RTV sealant is bad!
Quote:
![]() not directed at you Boog but your story reminded me of it ![]() ![]()
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I started out with nothing - and I still have most of it |
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#20 | |
Registered User
Join Date: May 2013
Location: Oregon
Posts: 327
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Re: Why RTV sealant is bad!
Quote:
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#21 |
Registered User
Join Date: May 2018
Location: Prattville, AL
Posts: 608
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Re: Why RTV sealant is bad!
This thread has some good examples of how the "the more the better" philosophy is bad. I do use sealant but as stated by others just enough to do the job IE: small 1/8" to 1/4" diameter beads. For the high temp I use spray on to make sure I get a seal and to make sure I don't over apply the sealant.
I was taught by my dad who permatexed everything. Old habits die hard..
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-------------------------------------------------------- 1967 C10 "Snowball" (Currently in a thousand pieces down from a bazillion) 1989 Toyota DLX pickup "The Hulk" |
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#22 |
Registered User
Join Date: Apr 2009
Location: Terre Haute, IN
Posts: 56
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Re: Why RTV sealant is bad!
I've read about people cracking intake manifolds they tried to remove after being sealed on with The Right Stuff.
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#23 | |
Registered User
Join Date: May 2016
Location: Henderson NC
Posts: 975
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Re: Why RTV sealant is bad!
Quote:
Use the right amount of the correct sealant and you shouldn't have a problem. There are some applications though where using the correct gasket without sealant is best. Certain intake gaskets already have a bead of sealer where needed and should be applied dry. The same for head gaskets. Last edited by garyd1961; 10-08-2020 at 09:23 PM. |
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#24 |
Registered User
Join Date: May 2016
Location: Oklahoma
Posts: 189
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Re: Why RTV sealant is bad!
True that!!!
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1971 C20 Custom Deluxe, HT383, 4L80E, 3.73 Locker, 4 Wheel Discs |
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