Sealant on crank and cam seals?
- Thread starter Spetz
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I just used a thin layer on motor oil on crank and cams.
Anything on outside surface of seal will just attract dirt.
Anything on outside surface of seal will just attract dirt.
On metal shell seals I use a non hardening sealer like Permatex High Tack or Permatex#2 on the outside rim, on rubber half round seals like are used on some valve covers I use Hylomar, alternatively RTV can be used but it will make removing an installed metal seal more difficult in the future than the high tack.
You may find this interesting.
https://blog.hemmings.com/index.php/2013/09/13/tech-101-how-to-use-the-right-gasket-sealants/
You may find this interesting.
https://blog.hemmings.com/index.php/2013/09/13/tech-101-how-to-use-the-right-gasket-sealants/
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The reason you want to use a sealer on steel shell seal being fitted in aluminum castings is the thermal expansion rate of the materials. Steel (seal shell) is 1.63 while the aluminum head is 2.73.
While the seal may fit perfectly tight at ambient temp when the engine reaches operating temp the seal can actually loosen in the bore slightly, this is not generally an issue but on some engines it is, some Subaru engines for example have a habit of developing loose camshaft seals and leaking oil as do some others.
The reason is simple, when the seal is installed in the casting a certain amount of "crush" force is exerted on the steel shell, once it loosens it can rotate making it even looser and in extreme cases cause some wear in the bore. Using a sealer does not cure the expansion but it does help prevent walking and leakage at temp.
The is automechanics 101.
Edit: Note that some seals have a sealing coating on them from the manufacturer, these need nothing additional.
While the seal may fit perfectly tight at ambient temp when the engine reaches operating temp the seal can actually loosen in the bore slightly, this is not generally an issue but on some engines it is, some Subaru engines for example have a habit of developing loose camshaft seals and leaking oil as do some others.
The reason is simple, when the seal is installed in the casting a certain amount of "crush" force is exerted on the steel shell, once it loosens it can rotate making it even looser and in extreme cases cause some wear in the bore. Using a sealer does not cure the expansion but it does help prevent walking and leakage at temp.
The is automechanics 101.
Edit: Note that some seals have a sealing coating on them from the manufacturer, these need nothing additional.
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On the FTO ? I've seen cam seals pop out of a dohc Diamante. They were the blue ones, and I think the guy how did it might've lubed them. One of those 4 o'clock friday jobs.
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