How heat and weather resistant is regular, household silicone

>>1226453
>regular, household silicone sealant/caulk?
>Will it last in an engine compartment of a car?

I would pick a brand and a type and google it.

>>1226455

I have some bathroom sealant at home and was just wondering if I can just use that instead of having to buy some high-temp grade stuff.

>>1226459
>I have some bathroom sealant

I would read the brand and type and google it.

>>1226453
roofer here
roofing silicone is pretty moisture/water resistant
dont know about heat though

>>1226470
>roofer here
>roofing silicone is pretty moisture/water resistant

My sealant is bathroom type. Can you find out about that?

>>1226453
Try some, see if it holds.

If it doesn't, use RTV silicone. It's made for head gaskets.

>>1226481
>Try some, see if it holds.

Thanks. I just wanted to get a second opinion. My exhaust manifold was leaking enough to make a lot of noise, so I'll try the bathtub caulk when I bolt it back on.

>>1226486

Thx 4 taking over my thread.

t. OP

>Will it last in an engine compartment of a car?

Use 3M 5200 or aircraft fuel tank sealant.

>Manifold

IS NOT THE FUCKING COMPARTMENT. For manifold, clean the shit out of the gasket surface with a wire brush, sanding etc then use the PROPER GASKET. A wipe of high temp RTV can help if the gasket surface metal is rough AFTER cleanup but RTV (high temp or otherwise) isn't a gasket.

Also next time post year, make and model because some engines have aftermarket gaskets available which address problems, such as nice thick gaskets for headers.

Brush some anti-seize on all your exhaust system fastener threads, even if you don't expect to take off those fasteners again. You'll thank me later. Anti-seize is love and a jar lasts many years.

>>1226501

OP here, just wanted to seal an ECU unit that attaches straiggt to the engine block.

File: Screenshot - 08122017 - 11:39:45 AM.png (119KB, 744x388px) Image search: [Google]

119KB, 744x388px

>>1226501
>A wipe of high temp RTV can help if the gasket surface metal is rough AFTER cleanup but RTV (high temp or otherwise) isn't a gasket.

wow. I've never noticed this before. They seem to say that it can be used as a gasket but I suppose that's for ideal surfaces that already mate almost perfectly.

and the anti-seize suggestion applies to just about anything in my opinion. You'll never have to fight rust or corrosion once you apply a thin film of this to the threads.

>>1226512
>OP here, just wanted to seal an ECU unit that attaches straiggt to the engine block.

What sort of ECU needs to be sealed to an engine block? Does it keep oil or coolant from leaking? And what type of "ECU" is it? Typically they are not mounted on the engine block.

>>1226526

Its the ecu box that has to be sealed actually, it sits on the back of the engine

>>1226534
>Its the ecu box that has to be sealed actually,

Sealed against what? Air and fumes? If you check the temperature rating of your bath sealant it might be ok since it doesn't have to deal with any sort of pressure, apparently.

Do you have pictures of this ECU, or can you find one on the internet?

>>1226540

Its just a metal box, pic related without the lid that has to be sealed. The box is bolted to the block.

File: post-12012-1288538653.jpg (1MB, 2560x1920px) Image search: [Google]

1MB, 2560x1920px

>>1226544

<---

>>1226545
There's supposed to be a rubber gasket in that groove.

Any silicone sealant will work is my guess. Doesn't have to be anything special.

>>1226501
>aircraft fuel tank sealant.
this dude knows his shit.

if you want something that works from -65F to +300F, sticks to everything and will last a fucking lifetime, go with the aircraft sealant.

>>1226550

Can it be reopened?

>>1226556
>Can it be reopened?

Probably not without a struggle, but why did OP open his in the first place? Did the factory seal deteriorate?

>>1226534
Remove all the existing sealant on case and cover, then use clear sensor safe RTV (cheap at any auto store) because some RTV uses acetic acid which isn't nice for sealing electronics. RTV will peel off for future maintenance.

If you never want to take it apart again and expect to use the vehicle offroading in wet nastiness, then I'd cough up for a tube of Semkit from Aircraft Spruce or find an "expired" kit on Ebay. They stay good long after the expiry date which is why I scored many expired kits in da Air Force. Now they track HazMat but it was glorious.

Aircraft sealant is god tier electronic potting compound too. I prefer the kits. You plunge the plastic rod into the black to ejaculate it into the body, then grab the plunger (which is screwed into an impeller) and turn it clockwise while stroking to mix. When color is even, use the sealant AND spooge a small glob into the bottom of an inverted soda can or similar (sheet metal troops have used soda cans since forever). When you expect it to be fully cured, cut your test blob with a knife. If it's cured, so is your part!

This works with most sealants and epoxies to verify cure so even if you don't buy aircraft sealant, remember the trick.

http://www.skygeek.com/flamemaster-cs3204b1-2kit-fuel-tank-sealant-6-oz.html?

Every mechanic should get a kit to play with. It's also an outstanding sealant for automotive use because it's "wetting" is outstanding. I only use it on surfaces where I want zero weepage, like old motorcycle engine case joints, because it's a bitch to remove.

Wear disposable gloves and have rags, not paper towels, to wipe with.

File: un.jpg (118KB, 950x534px) Image search: [Google]

118KB, 950x534px

>>1226569
>ejaculate it into the body
>turn it clockwise while stroking
>spooge a small glob

yeah baby

>>1226545
What I would do:
Go buy a small tube of RTV silicone (100% silicone/"room temperature vulcanizing", etc. somewhere. Should cost you around $5. It has a max temp of around 600F. For your application, you do not need any other additives to retard cure time, resist mold, increase adhesion and so on. Remove the board from the housing, then scrap/sand off all the old gasket material. Wipe the housing with the gasket groove with mineral spirits to completely remove oil residue, then pipe a thick bead of the RTV in the groove. Allow it to fully cure for some hours, ideally 24. Put the board back in, and screw the two halves of the housing back together. The pressure of the two halves will squish the rubbery bead down and create a good seal.

>>1226453
no they aren't very resistant to grease and oil - they absorb them and swell which weakens them.

You need one rated for gaskets