Guys
Over the winter I renewed my thermostats, using Stant Superstats, which have turned out to be really well made items, the two of which opened perfectly in synch when tested. I also bought OEM gortex/metal sandwich gaskets.
These latter have turned out to be a disappointment, and weeping gaskets have led to me having to replace both OEM gaskets with home-made paper ones, using a smear of hi-temp copper RTV on each side.
I used this sort of stuff in about 1mm thickness (Autozone have similar for you USA types):
They have worked a treat. Making the gasket is pretty straightforward, and for those who have never done it, this is what I did:

• place a suitably sized bit of gasket material over the thermostat cover join,
• using a ball-peen hammer (rounded end of a hammerhead) lightly tap the fixing holes until the material separates. Repeat and all round the big water hole,
• carefully cut the material where it has not fully separated using nail scissors (this happens on the water hole most often)

Clean up the ally surfaces to remove all traces of the old gasket, and rough them up with some emery paper. Smear the ally or the paper each side with hi-temp RTV and fit. The OEM gaskets are pretty pricey, so this is both better and cheaper.

 

The "OEM" style gaskets you bought had metal in them? That is really strange for a cooling system gasket.

I've changed my thermostats twice, and I'd much rather just make the gaskets than wait to ship (and pay shipping $5x as much as the gasket).
You can just buy gasket paper in a roll at any auto store. Its generally blue or black. No sealant needed. Really nice to have some laying around for whenever its needed. Its pretty easy to make a gasket work, becomes a bit more challenging to make it pretty. Razor blades and punches are key and having some prussian blue makes things really easy.

 

I’ve never had a problem with the metal sandwich gaskets. What I like about them over paper is you don’t need to replace them if you take the thermostat housing off for whatever reason. When you use them on the cam covers you don’t need a sealant, which always makes for a cleaner looking installation (no sealant ooze!). I did a leaky 83 V12 engine reseal... valve cover, sandwich plate, oil pan, oil filter block all in metal sandwich gaskets and it’s been leak free for ten years.

 

Agreed. It is only in this particular application that they have not worked.

 

Maybe the covers weren't tight enough? :iono:

 

That is possible, but I think this sort of stuff is generally over-torqued. A t-stat housing is the kinda thing someone will just do by feel and unknowingly crank up to 20-30 lb/ft when the spec is more like 14 lb/ft

Also the sort of thing where sequence isn't as important, so people don't pay as much attention to it, but the tightening sequence and stepping the torque up over 2-3 graduations may have been important for the metal gasket used. Could have also just been a crap gasket.

I've never had any problem with using dry paper gaskets in cooling system applications. Usually the stuff "for" cooling systems is blue and a bit thicker, so there is a lot of compression and room for imperfections in the surface. Maybe a bit of sealant to keep things in place

 

Crap gaskets also in that application.

I did Gregs thing, made my own, the same way, its an age thing, learnt before minor gaskets were an item readily available, and gasket paper was plentiful in various thicknesses, and grades, such as Water, Oil, Fuel spec.

My V12's all survived without minor gaskets at all, just Hi-Temp RTV, beeeeautiful.

 

I think it is worth pointing out that one should probably use dry paper gaskets alone of RTV/hylomar alone. Its the combination of the two that often create a nightmare as far as cleaning goes.

 

Mmmmm, I assume you mean cleaning whe replacing the compoent where RTV has been used????

Agree to a point, but I have a small selection of "toothbrush" wire brushes. and that sorts the "old stuff" pretty smartly.

Too much RTV by some earlier fool is the worst.

One stubby per hour doing the cleaning, must keep the fluids up as we get older.

As always though, we all have our favourites, and that is FINE.

I dont use gaskets on Auto Trans pans either, just a bead of RTV, and 4 guide studs, slide the pan up, a few bots to hold it "just firm", tighten 1/2 turn tomorrow morning, after the "hair of the dog". This has raised the heckles of many over the years, but I dont have trans pan leaks, whoopee.

 

I prefer a semi-setting gasket paste to RTV, together with a gasket, as it won't block passageways if it gets loose. Permatex #2 is widely available in the US, and it has never let me down on cooling system parts.

 

Permatex #2 has served me very well over the years as well.

Cheers
DD

 

My view on gaskets of any specie is that they rely on flat clean surfaces and proper torque. More of the latter can be destructive. Just right is the goal.


Just checked on Billy. Sunning and grazing !! What a life !


Carl