# Gasket sealer: yes or no?



## Cabin Fever (May 10, 2002)

Okay guys, I'm a little embarrassed about asking this question, but here goes. When ever I've replace a cork or composite gasket on a vehicle or pump part I've always smeared both sides with gasket compound. A co-worker told me that you don't have to do that. Have I been doing it wrong all these years?

So what do you say? Compound or no compound? If you use a gasket compound, what kind to you use? (I use Permatex #2).

And yes, I often use silicone instead of any gasket at all..depending on part.


----------



## WisJim (Jan 14, 2004)

I usually use just enough gasket sealer on ONE side of the gasket to hold it in place. It is the gasket that provides the seal, not the gasket sealer. In some situations a gasket sealer-type of material is used instead of a gasket, especially the silicone-caulk type of gasket stuff.


----------



## michiganfarmer (Oct 15, 2005)

Unless the part comes with a groove, and an O-ring, I always use Permatex. I buy the red high temp so I dont have to keep miltiple tubes around


----------



## fordson major (Jul 12, 2003)

well we do it like you do cabin! had no problems so don't plan on changing, little extra insurance to stop the fertilizer from hitting the fan (actualy) as moving at a high pressures it can work its way through a bad seal. duct tape only goes so far!


----------



## tyusclan (Jan 1, 2005)

I agree with ford major. I usually silicone both sides. It may not be necessary, but the sealer is relatively inexpensive, and it's worth it to me to possibly prevent a leak.


----------



## agmantoo (May 23, 2003)

Probably all the techniques work and work equally well. However, I am the person that may have to remove the gasket in the future so I do the one side if I need the sealer to hold the gasket in place during assembly. I stick the gasket to the component that will be removed from the assembly and therefore I have little cleaning to do in the tighter space on future disassemblies. On thermostat housings where typically there are only 2 bolts and a lot of distance between I do apply sealer to both sides as an aid to prevent the gasket slipping outward. If the bolt pattern is good and there is no problem with assembling the device, I do not use sealer.


----------



## ace admirer (Oct 5, 2005)

the problem is: too much/too soon makes a mess and can cause damage inside fuel and oil passages... i try not to use it unless something unusual is going on. like a cracked and repaired casting at gasket area. but....you see more and more NEW auto engines put together with the stuff.


----------



## wilderness1989 (Feb 23, 2006)

agmantoo said:


> I am the person that may have to remove the gasket in the future so I do the one side if I need the sealer to hold the gasket in place during assembly. I stick the gasket to the component that will be removed from the assembly and therefore I have little cleaning to do in the tighter space on future disassemblies. On thermostat housings where typically there are only 2 bolts and a lot of distance between I do apply sealer to both sides as an aid to prevent the gasket slipping outward. If the bolt pattern is good and there is no problem with assembling the device, I do not use sealer.


I agree with this and as I turned wrenches for a living at General Motors dealerships for over 30 years I can talk from experience. In all that time you could probably count 10 or less times I used red Permatex other than thermostat housings and water pumps. If you pay attention, clean the surfaces properly, and position the gaskets properly there should be no need to slather on the sealer. Exceptions are surfaces that are made specially to be sealed with silicon sealer only and the end gaskets under GM V-8 intake manifold gaskets on which I use 3-M trim cement, tan from a tube. :cowboy:


----------



## Beeman (Dec 29, 2002)

Cabin Fever said:


> Okay guys, I'm a little embarrassed about asking this question, but here goes. When ever I've replace a cork or composite gasket on a vehicle or pump part I've always smeared both sides with gasket compound. A co-worker told me that you don't have to do that. Have I been doing it wrong all these years?
> 
> So what do you say? Compound or no compound? If you use a gasket compound, what kind to you use? (I use Permatex #2).
> 
> And yes, I often use silicone instead of any gasket at all..depending on part.


 Generally the box the gasket set comes with will tell you what is recommended especially Fel-Pro gaskets. Most only recommend a contact cement for holding the gasket in place which is all I use on gaskets that need holding. Gaskets that don't require holding in place I don't use anything on. In some cases like a transmission oil pan that's a cork gasket I might use a little grease for retention.


----------



## chuckhole (Mar 2, 2006)

110% totaly agree with Wilderness1989.

I used to work as a mechanic too. When tearing down engines, I saw nothing but trouble when people used gasket sealer. This is what I have found from my observations:

Do not use gasket sealers when sealing parts that are keeping in/out any petroleum products. The heat, oil or gas will eventually break down the sealers and they will fail.

For cooling system parts (water pump, thermostat, etc.) I always used the Permatex Copper spray or gasket spray.

Do not use silicone for anything except glass/plastic to wood/metal/fiberglass. Silicone must be completely removed before recaulking. After silicone dries, nothing else will stick to it, not even more silicone.

For general metal to metal/fiberglass (not engines), use polyurethane adhesive caulk. This stuff is so good, it almost sticks to water.

For wood to metal/fiberglass, use polysulfide adhesive caulk. It stays pliable so that it will move as the wood swells and shrinks with movement and moisture.


----------



## RACCOON (Dec 13, 2005)

I've always just used grease.
cheaper and won't mess up anything


----------



## spam4einstein (Sep 11, 2005)

Makes me cringe!!
Horible stuff unless it is absolutely needed. Too many shade tree mechanics glob the stuff on and it gets loose in the engine then picked up and clogs the passages and destroys engines and other parts. I use it if I have a gasket with a tear and dont have a replacement on hand, just use it at the tear. The worst is the guys who think RTV silicone is "perfect" gasket replacement for dome covers. Some of the very high quality gunk is great when its called for, like toyota oil pans.


----------

