Which Hylomar?

[Member 10617]

Can anyone give me some advice on which Hylomar product to use when applying sealant to gaskets:

Hylomar AF?
Hylomar M?
Hylomar Universal Blue?

Also, I like to put a bit of gasket sealant around certain bolts and screws where oil seepage is sometimes a problem. Which Hylomar product would be best for that use?

 

[TR4nut]

Ed-

I will likely get vetoed by others - but frankly after using Hylomar Universal Blue for about a year I'm going with Permatex. It does indeed allow you to save gaskets if you need to make up a joint more than once, but it also is fairly pitiful at holding back oil drips. Just my experience.

Randy

 

[DNK]

Universal Blue here

 

[TR3driver]

+1 on Universal Blue (which is not the same as Universal Blue Racing Formula). Seems to work well on straight threads (like bolts into the engine block) too.

I do use Permatex #3 Aviation in a few places (eg Figure 8 gaskets), but it is a royal PITA to remove after a few decades of service (I use a BFH to remove the liners).

But the important thing with either one is to be sure that the surfaces fit together snugly, with no burrs, high or low spots. For sheet metal covers (eg rocker cover, timing cover, etc), that usually means doing some hammer & dolly work to get the surface flat & true again. For places where castings join (eg thermostat cover), I lightly rub a flat, fine tooth file over the surfaces to pick up and show high and low spots. It's really amazing how often something shows up.

 

[Geo Hahn]

In my experience Hylomar (Blue) works best when there are either:

(1) very flat mating surfaces (e.g. the thermostat housing) or

(2) a gasket with lots of give (e.g. a thick cork valve cover gasket)

For a stamped sheet metal part (like an oil pan) with a 'paper' gasket I find that Hylomar is not enough to seal the inevitable imperfections of the mating surface even if a lot of care is taken to pound out the dimples that develop around the bolts holes.

For the oil pan gasket I have had some success by using a suitable RTV on the pan, laying the gasket in place, covering the whole thing with a piece of glass and weighting it down (can goods) until it is totally set. The result is a very flat surface of the paper gasket which will then seal well against the block with Blue Hylomar.

When the day comes to undo the business the pan & gasket will come away from the block easily -- I will still have to attack the RTV but that isn't too tough to do with the pan on the workbench where effective implements of destruction can be brought to bear.

I don't bother to seal the threads of the oil pans bolts (if that is what you're suggesting) but there are bolt threads I do seal, such as the bolts that hold the coil bracket to the block. There I have been using Teflon Thread Sealant (from the plumbing section at Ace Hardware).

 

[Member 10617]

I have been using NAPA Permatex #2 Form-A-Gasket non-hardening sealant, mainly because it is readily available around here (we don't have many choices). It is a bit of a mess to apply (I use a small brush), and it doesn't clean up easily (same as Randall says), but it seems to do an OK job.

So far I haven't replaced any gaskets, so I don't have any experience with them and sealants.

But I have used the Permatex to try to cut down on the seeping around some bolts. George -- you are right: I have used it around the threads of the oil pan bolts and have had good results, so far. Adding lock washers to the bolts has also helped.

The guys at TRF suggest using two of their paper gaskets on the oil pan. If I replace that gasket, I may try that.

George -- is that Teflon Thread Sealant you use the tape variety or a paste? Any problem with bits of tape wandering off to cause problems?

I know that it is impossible to stop all the leaks on these cars, but little by little I am getting it down to a minimum. No pressing reason for this attempt except.... it is a challenge!

 

[Geo Hahn]

...is that Teflon Thread Sealant you use the tape variety or a paste?

 

[TR3driver]

Note that, strictly speaking, that stuff isn't a "sealant" at all. It's actually a high pressure lubricant, so you can screw the TAPERED pipe threads together until the fittings distort and seal metal-to-metal.

Not the right thing to seal straight threads, IMO. But to some extent, anything that sets up over time will do, even paint.

PS, same goes for the "teflon" tape, which IMO has NO place on a car, even on the very few fittings that have tapered threads.

 

[Member 10617]

Has anyone used fiber washers and sealant on bolts to stop oil weeps/seeps?