Gasket maker or install OEM paper gaskets dry?

[WildCoast]

Always wondered why some people use the grey RTV silicone type gasket maker vs just using the OEM paper/metal gaskets and installing them dry?

The only time I've seen gasket maker specified in the Honda or KTM service manuals is a tiny bit on the seam between the two bottom end halves (to help the cylinder gasket seal better around that seam). Otherwise I've heard recommended simply greasing the paper gasket which just helps with removing it in the future (doesn't get baked onto the case as much).

I've also heard some sort of copper gasket maker recommended, again, what's that and why?

 

[GMBoy]

It depends on what the OEM says to use. If RTV is called for that is what I use. If a gasket is called for then I will use that.

 

[Timmastertech]

Our standard procedure in my shop on paper gaskets is we use high tack gasket cement on both sides. This serves to hold the gasket in place while installing the part and to fill any small imperfections in the sealing surfaces. Ive never been a fan of smearing RTV on perfectly good gaskets. The only time we use silicone with a gasket, unless directed in service information, is if we have problems with the sealing surfaces as a last resort before replacing castings or if replacement parts are not available. My preference in that case though is to fill the voids with epoxy and flat sand but thats not always practical.

 

[The_Jeff]

Some OEM paper gaskets are cheap (thin) and only work on new, perfectly flat parts. I'm thinking of thermostat outlet gaskets from before when they went with o-rings. I'll give those a light coating of RTV to fill in imperfections, but not enough to ooze out when things are torqued.

 

[gman2304]

I had the diff oil changed a few years ago in my Chevy truck. The shop used a gasket and the cover was leaking within 24 hours. Took it back and they drained it and used RTV only and it was dry when I sold it 5 years later. Of course YMMV.

 

[WildCoast]

For context, this is going on a Honda XR650L, I couldn't find any reference for RTV or other in the FSM, but that FSM is from the 90s and pretty basic.

 

[CleanSump]

I use Permatex High Temp Spray a Gasket on paper ones. The copper spray on copper gaskets. It holds them in place during assembly and I think it helps seal.

 

[grasscutter]

This thing makes life way easier.

 

[Carmudgeon]

I fixed seepage from a brand new thermostat housing and paper gasket with hylomar, which also holds it in place.

Non-setting, acetone cleanup, no scraping in the future.

 

[nobb]

I prefer gaskets for parts that need to be serviced. eg. diff cover, transmission pan. There's usually no need to use anything extra, but if the surfaces are less than perfect then there's special gasket sealers. No RTV ontop as in theory it is slippery and affects torque, meaning thin portions of the gasket could squeeze out.

 

[97K15004WD]

When available, I substitue "rubber" gaskets in place of paper gaskets, or RTV. For example, on my transmission pan. I change fluids with a "drop and fill", so a reusable, non-sticking solution is easier. Same on differentials - Lube Locker type. Works great, but YMMV.

 

[KrisZ]

For context, this is going on a Honda XR650L, I couldn't find any reference for RTV or other in the FSM, but that FSM is from the 90s and pretty basic.

What are you sealing? The clutch cover, the engine halves? If it’s something that will need to be removed later on, like a cover, I would use a gasket and silicon only in the spots where cases meet.

 

[danstraylee]

What are you sealing? The clutch cover, the engine halves? If it’s something that will need to be removed later on, like a cover, I would use a gasket and silicon only in the spots where cases meet.

I use high tack sealant both sides on infrequently removed parts on my moto bikes such as case halves. A smear of grease on cover and cylinder base gaskets that I'm removing frequently.

 

[Lubener]

I would not use RTV on a gasket. Use either or. I do use Permatex 2 (thinly) on one side of the gasket to just hold it in place during installation.

 

[nthach]

I use Permatex high tack or similar on paper gaskets. No RTV.

 

[The_Eric]

High tack or Permatex Aviation Form a gasket for paper type gaskets