I've got a slow leak on my 01 Altima on the upper radiator hose flange that bolts to the head. It does not seem to use a gasket and just requires some sort of sealant to go between the hose flange and the head. It looks like there is some sort of silver sealant in there from the factory. I found some grey/silver silicone sealant at the auto parts store and I am wondering if this is the best stuff to use on these fittings.
What is the best sealant to use on metal to metal?
- Thread starter wymi
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Kestas
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I can't tell from color, but you should probably use an RTV sealant that is heat resistant. In my toolbox that's a red sealant manufactured by Permatex.
Permatex Hi-Tack spray works really well for metal-to-metal, no gasket applications. The can I have states that it will handle temps up to 450f.
Permatex black rtv is best. I use it a lot. If you can find black silicon weatherstripping glue, this stuff works very very good!
BtB
BtB
I like permatex ultra-black.
Thanks for all the suggestions. My concern is that if I use a silicone sealer won't it just push out when I torque the bolts? I was thinking of buying a sheet of gasket material and cutting a gasket to fit and then use good old Indian head gasket shellac. I've never had a leak using Indian head on gaskets for many years. Anyone know the reasoning on why Nissan does not use a gasket in that application?
For my thermostat housing shop manual specifies RTV. But it's a little bit tricky than cutting the right dia nozzle and laying 3mm bead in continuum... You should also know when, and how much to torque the bolts for best seal... Even when everything is ok some red flakes will circulate through the coolant lines.
Last time at the store I bought the plain paper gasket... it was fitting perfect, soaked it in water to soften it to take up the slightest crevices. Then I've torqued the bolts right up. No problems at all. Easier, no wait, looking neater, cleaner, also cheaper considering the next time a DIYer will use the sealant all the tube will be a stick of rubber. If surfaces are smooth and aligns well I don't think you'll need anything "exotic".
Kestas
Staff member
I can take a guess.... RTV in bulk is cheaper, plus they don't want to stock an extra gasket that they have to keep in inventory. They probably already have RTV in stock for other applications.
If making a gasket works for you (I make all mine), then by all means use it.
As far as using RTV silicone gasket compound, this is how I use it:
1. Start with an absolutely clean surface.
2. Squeeze a ribbon of compound on the sealing surface.
3. Install the part finger tight so the gasket surfaces are seated (this'll squeeze out the excess compound).
4. After the RTV has cured, torque bolts to the final torque.
If making a gasket works for you (I make all mine), then by all means use it.
As far as using RTV silicone gasket compound, this is how I use it:
1. Start with an absolutely clean surface.
2. Squeeze a ribbon of compound on the sealing surface.
3. Install the part finger tight so the gasket surfaces are seated (this'll squeeze out the excess compound).
4. After the RTV has cured, torque bolts to the final torque.
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