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To GOO or not to GOO - That is the question

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LeeMcKee

LeeMcKee

Jedi Hopeful
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I'm doing a check on a friends transmission and as I'm replacing all the gaskets and oil seals I had a question for everyone here. I've worked for mechanics that use "Goo" to seal up paper gaskets and I've worked for others that would never use anything as a religion. I know that the factory never sealed paper gaskets but what do you guys do?
 
I've done 'em with thin film of oil, thin film of RTV, thin film of Hylomar. Had no leaks from any of the three, RTV gave me the best "feeling of security" tho. Some boxes (Porsche and Alfa come to mind) are metal-to-metal with a "special" case sealant. Porshe gets $40 for a small (4oz, IIRC) bottle of their stuff. Works great but I think I'll stick with RTV for LBC's. /ubbthreads/images/graemlins/wink.gif
 
As a general rule I don't like RTV, but I do from time to time use Permatex Form-A-Gasket and their thinner aviation stuff. An example would be a very thin smear on the faces of the OD steel plate where there is no OEM gasket makes me feel better too.

When you use RTV it should only be applied in sparing quantities, never to over compensate for really poor surfaces. Remember that when you use enough goo to have it squirt out from between the surfaces like jelly on a sandwich, it is also squirting out INSIDE the cavity. If a lump of it breaks off it might get into someplace it isn't supposed to be, like an oil passage or a needle bearing. Beside it looks very unprofessional, especially the blue goo.

Jack
 
"Film" is the operative word here. Should NEVER see it squitterin' out from between bits!
 
I like to use a little Hylomar on the gaskets. I put a little on each side then squeeze it around with my fingers pinching the gasket so that the coating is very thin.
 
Depending on the application I do what the DR does apart from Hylomar which I've never worked with. For most surfaces where I want to take things apart later I use Aviation Form-a-Gasket (the thin stuff mentioned above). Where I'll be leaving things for a long time I use RTV and I clean the outside after assembly to hide the blue squirts mentioned above. Remember, NEVER use RTV on anything exposed to gasoline.
 
See how I'm stayting out of this one...hehehehe
 
I use the Hylomar *spray*. A couple of short spritzes and you get the perfect amount every time.

I use a film of RTV in two cases: water pumps/stat housings and where there's a serious nick on a mating surface.
 
More regarding RTV....

Obviously it doesn't matter much on MGs but NEVER use that stuff on a car equipped with an oxygen sensor. In fact don't even open the tube if a sensor is nearby. Most times it won't do anything but all the other times the "fumes" will trash the sensor or even worse partly trash it. At least if is shot dead you know what you are dealing with, but if it still twitching it might cost you even more money trying to figure out the cause of the running problem on top of the cost of the sensor itself.

Jack
 
There was a BIG problem with this at the introduction of O2 sensors. There are now some "RTV" like sealants that are "sensor safe" but I'd read some data and make sure it said "Permatex" on the tube as well... Their "ULTRA GREY" is one such. just a word in yer ear, there.
 
Most of the auto parts suppliers are now carrying it. The spray isn't as "economical" as a tube, but it does meter it out more uniformly... but I LIKE gettin' me digits in it. I'm a tactile kinda guy. /ubbthreads/images/graemlins/wink.gif
 
[ QUOTE ]
Most of the auto parts suppliers are now carrying it. The spray isn't as "economical" as a tube, but it does meter it out more uniformly... but I LIKE gettin' me digits in it. I'm a tactile kinda guy. /ubbthreads/images/graemlins/wink.gif

[/ QUOTE ]

Hunh. I have a heck of a time finding it in a tube. When I see some, I usually buy 2 or 3 tubes just so I won't run out. I've probably got a 50-years' supply right now! ;-)
 
I'm going to try the spray Hylomar. That is a great idea.
It's kind of like the best of both worlds. A super uniform thin film but It's hylomar so you won't have to worry about it until the day after doomsday.
"Belt with Suspenders" is what my old boss used to say.
 
There can be a caveat, Lee. The thicker, cork gaskets (V/C gasket, pan gasket, gastank sending unit, etc) can have a tendency to "squirm" and Hylomar can actually aid that action if used on both sides of the gasket. It never "sets". Usually a "tin side" use of RTV and "face" side of Hylomar is a better application. Paper gaskets, both sides.

Just so's ya know. /ubbthreads/images/graemlins/wink.gif
 
There's only one word in sealants for British Cars:

MARMITE

Although I did use a thin film of clear RTV on the OD sump cover the other day and it hasn't leaked a bit.
 
And Vegimite down under...?
 
[ QUOTE ]
Hylomar on thin gakets, nothing on cork.

[/ QUOTE ]


/ubbthreads/images/graemlins/savewave.gif---Provided it is rubberised cork!---Keoke
 
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