Which silicone is best.

[Lyndon302]

Which silicone is best. The strong smelling one like vinegar or the non smelling one
Why I ask is I have a chain cover leak I have tried to fix with. 3 bond ( rubber type ) twice and now 574.
The latter being by far the worse result.
I had a leak on the rod locating plate on my gearbox. Same deal could not fix it with the above.
I used the non smelling silicone and it's fixed. So next I'm going to visit this chain cover again.
What I do is clean. Clean and clean. Silicon and lightly tighten. After 24 hrs I properly tighten. This creates a silicon gasket. ( This is my next step on this chain cover.)
I believe it's slightly bent from a rear end crash or similar. I had it straightened a few years ago but it's never been right.
It's leaking where it mates to case. ( 3 bolts 67 aluminium )
Thanks lyndon

[OSC911]

Hi Lyndon
I use the Toyota Seal Packing for everything that requires silastic. It is O2 friendly and black in colour. You get it from your local Toyota dealer. I hadn’t ever used it when I was a mechanic but did two years at a Toyota dealer and was sold on it. I did most of the engine jobs and used it extensively. I have used pretty much every sort of silastic out there and it is outstanding. Easy to use and has a really nice working time. About $30AU - so I little bit more expensive than others but we’ll worth it.

[Lyndon302]

Thanks. I wonder if it's silicone 3 bond.
If so Japanese made might be good stuff.
Lyndon

[OSC911]

Not sure but it is definitely made in Japan. I am sure this will sort out your problem. Has gotten me out of more than one bind over the years.

[dannobee]

Try putting on the sealer then tightening everything down at once. Don't overthink it; that's how it's supposed to work. Make sure everything is spotlessly clean by using brake cleaner and a scotchbrite pad (by hand, do NOT use the rotary tool attachment!).

[Mark Henry]

I use loctite SI 5900 which is Porsche spec on 996 etc engines.
I agree the surface must be beyond spotlessly clean.

[stownsen914]

Wheel companies that use silicone to seal 3 piece wheels say not to use the vinegar smelling silicone as it attacks the aluminum

[al lkosmal]

Everything you wanted to know....and more

The Complete Engine Sealant Thread...

[JoeMag]

Are you using three bond 1184 grey stuff or 1211 white? I like 1184. If ya put the 1184 on both surfaces, let it dry a bit, it seems it could fill quite a big gap.

[Lyndon302]

Grey stuff. Worked ok. The 574 is useless.
Will give silicon a go next.

[Richey]

I'm using 574 on my cars - dry !

[Gordo2]

Are you using the sealants with or without gaskets?

I've had great results using silicone sealants with gaskets (very light coat each side before installing).

Meanwhile, I've fortunately not had to re-do my work - I'm sure the gasket material is well bonded in places.

Good luck

[Lyndon302]

I've always used the gaskets.
Lyndon

[JoeMag]

Just a thought…. You may want to put the box on a flat surface (glass) and use feeler gauges to see what size gap you’re trying to fill ( and where the actual gap is). I have previously wet sanded that surface on glass w 400 grit sand paper to make flat.

[Lyndon302]

I will certainly look at that.
Lyndon

[Jeff Alton]

Please show a picture of your leak.....

Is it the box to case or the cover to the box???

[Mark Henry]

The box and cover has to be square, if not it has to be repaired or replaced.

[Jeff Alton]

Originally Posted by stownsen914

Wheel companies that use silicone to seal 3 piece wheels say not to use the vinegar smelling silicone as it attacks the aluminum

For wheels you want to use a Silicone Adhesive, not a Silicone Sealant.... There are a few very good products available for this application.

[Lyndon302]

Originally Posted by Jeff Alton

Please show a picture of your leak.....

Is it the box to case or the cover to the box???

I've got a WTB in the appropriate section.
Lyndon