Thermostat-gasket sealer-yes or no ?

No

 

I know it's not proper but, before I made a gasket out of a cardboard from the back of a pad paper and used it on my thermostat housing and lasted me for five years without any sealant and not a single drop of watter. Make sure you torque that bolt for the T-stat housing properly and not to over tightened it.

 

Unfortunately no, I just went with my 25 years of experience feeling, I do so much of this in the past I can preety much feel it.
But I wouldn't go over 10lbs

 

Silicone as a gasket substitute is never a good idea. If you use too much (as many people tend to) little blobs will squeeze into the water passage and eventually break off. One can imagine the problems if it then got caught in a narrow coolant passage. My thermostat uses a cardboard gasket, no sealent. It's never leaked.

Ken

 

What does the manual say? All cars are different; when my thermostat died (stuck open) I found I didn't even have a paper gasket! It had nothing, nada, but wasn't leaking. My manual said to use a paper gasket so I did when I replaced it. My point with not using gasket goo is that if it's not needed, you're risking a problem if you're sloppy with it. If your car leaks coolant without it, then use it but not too much.

Ken

 

You should be able to find a website on line that will show you the correct or quite close to the correct torque. You simply have to look up the size of the bolt and know the thread pitch (by measuring it) and you will get an idea of the torque. I say idea because other factors come into play like what type of plating the bolt has, what strength it is (8.8 etc.), if the threads are lubricated etc. For a small, non-critical bolt like this it's really not important. I'd be more concerned with stuff like head bolts, wheel bolts, suspension bolts. Do you have a torque wrench that will actually be accurate at such a low torque setting for these small fasteners?? If not, there is not much point to all this anyway.

If you're still not comfortable with that then used the lowest torque you see listed for the fastener. If there's any seepage/leakage then tighten a bit more. Kind of like brass fittings.... if anything, undertighten. If the joint leaks/weeps then snug it up a little more until it stops.

I would just tighten them gradually in sequence using a small ratchet (1/4 inch) until they feel snug. You can use Loctite if you're worried they will loosen. More importantly the Loctite may reduce or eliminate the chance of corrosion on the threads for when you want to unscrew them again 5 or 10 years down the road.

 

Loctite?? Use the wrong type and you'll need a torch to remove the bolts! I would NOT use any Locktite on a thermostat housing! I wouldn't think the bolts coming loose is likely anyway if snugged down even close to what's reccommended.

Ken

 

I like permatex aviation sealant, particularly on old parts with a bit of pitting. The gasket should seal witout it, but it will seal with it...every time, and I hate doing things twice.

I never though about loctite on the threads (the purple, not the red) for corrosion control, but it's not a bad idea. I generally use neversieze as long as there is a lock washer, if not there's no lock washer the loctite seems like a good idea anyway.

 

Yes, and use the wrong tire (speed rating) on your Ferrari and you could have an accident. Drop a lit cigarette in the forest and you may start a fire.

Disclaimer: Okay, do not use the wrong type of Loctite. Objects in the mirror are closer than they appear etc. etc.

If the bolt threads corrode they may not come out either. My concern was more about preventing corrosion than worrying about the bolts un-doing themselves.

 

If the surfaces are smooth and flat it should seal fine without anything else.

 

I would venture that if corrosion is a problem, you need to change the coolant more often. For cars that expect to have deferred maintenance, you make a good point. I use anti-seize on spark plug threads only. On my car at least, things tend to fall off as it is so I don't need to encourage them! *S*

Ken

 

No arguement there. I change coolant every two years (and brake fluid every year). But, corrosion could be there from neglect by previous owner(s) too. Also, I would venture to guess that not every owner is as conscientious about coolant change as we are or maybe even aware of the effects. Hell, I bought a $200 digital pH tester to check coolant on my cars. Tells a lot and can be used to check pH for many other things. Much better and much more accurate than those test strips.

 

Hello from Germany,

if one uses the wrong Loctite the studs will come out of the housing together with the nut. Nothing more. The blue Loctite stuff 243 is the most appropriate product for most applications on our cars. Prevents corrosion, secures the nut or bolt and you can undo them with normal tools.
But for your initial question. I always use a tiny amount / thin smear of a non harding sealant on most paper gaskets. I would call it 'gasket-optimizer'. Never had a leak and never had problems with sealant seeping into the internals.

Best Regards

Martin

 

Using it sparingly on the plugs is very good.
I also use it on every bolt that goes into aluminum and any bolt that goes into the exhaust.
And on my wheel splines. And axle nuts.

Things like threaded rocker studs get the correct type of thread lock.

The stuff is great. Sparingly. We use it on aircraft all of the time and most of the material on aircraft is some type of aluminum.

 

+1 Exactly.

 

I like the red, spray Permatex. It puts a thin coat that (I hope) would help seal thru some pits and it is real easy to get back off.

BTW, it is a good idea to open the bleeders while you are pouring the coolant in. If you wait until you are all done, you may trap some air in the system.

Mark

 

To late to help the original poster, but I recomend using Aviation Permatex on paper/cardboard gaskets. It is pretty thin and you just brush a light coat on both sides of the gasket. It was originally designed to seal the two crank case halfs when assembling opposed aircraft engines so it takes heat pretty good and is oil resistant. I would not use it in high heat applications.

For anti-sieze compound I use Never Seez Pure Nickel Special, another product used extensively in aviation, on spark plugs, jet engine igniters and boroscope plugs. Just use a LITTLE, on the bottom couple of threads is all that is necessary

 

i used the permatex hypolon - it remains very soft and the parts are very easy to remove if needed. jon s