Permatex Motoseal vs. Ultra Grey: Sealing Engine Halves, Valve Covers, Rear-end Covers; Metal to Silicone Pipes

Permatex Motoseal vs. Ultra Grey: What’s The Difference?

Permatex Motoseal vs. Ultra Grey: Specs & Uses

Technical Info

	Motoseal	Ultra Grey
Review Rating	★★★★	★★★★★
Datasheet	📥Permatex Motoseal	📥Permatex Ultra Grey 82194
Chemical Type	Synthetic rubber	Oxime silicone rubber
Color	Gray	Gray
Odor	Solvent	Low odor
Specific Gravity	1.20	1.47
Flash Point	87°F	>200°F
Oil Resistance	Good	Improved
Chemical/Solvent Resistance	Good – oils, gasoline, etc	Good – oils, antifreeze, alcohol
key Applications	Motorcycles, ATVs	Valve covers, oil pans, transmission pans

What Is Permatex Motoseal

✅Pros

Just a small amount applied with my finger was enough to create a reliable seal. I have tried various gasket materials in the past, but this is the first one that actually worked. It’s impervious to oil and gas, making it a foolproof choice.

Sticking Power

I also use it as a dressing instead of a gasket maker. This stuff sticks like crazy. Because it’s thick, I even used it to plug up leaks on some equipment. My four-wheeler had a leaky petcock, and after applying this sealant to the edges, it stopped leaking. Fuel and ethanol don’t bother it.

Fix Leaking Valve/Line

The leaking valve/line on the gas-powered tractor was causing a slow drip. I tried using a regular gasket maker, but it didn’t work. Then I removed the gasket maker and applied Permatex Motoseal while it was still dripping. It didn’t take long for the drips to stop. I was impressed with its effectiveness. It’s been months since then, and I haven’t experienced any drips.

Motorcycle Case Halves

Besides chainsaws, Permatex Motoseal is great for motorcycle case halves, clutch covers, and any other area that needs a reliable seal. It works great.

❌Cons

Now, let’s address some concerns. Permatex Motoseal does not necessarily work for this situation:

So as you can see while Installing intake, Motoseal is not that ideal. It is better to use the “Right Stuff” which dries pretty quickly 😌 and you can see it in my analysis of permatex the right stuff grey vs black. I use it on truck rearends if it needs to be done the next day, holds up well.

A better option is Pro Seal 80726 Red Hi-Temp RTV Silicone or the following one: Permatex Ultra Grey.

What Is Permatex Ultra Grey 82194

✅Pros

The price and size of the tube were great, giving me excellent value for my money. I used it on the block and head connections of my WRX EJ255 engine to dry-deck it, and I’m happy to report that there were no leaks on my 19-pound cooling system.

Cost Savings

One of the standout features of Permatex Ultra Grey is the cost savings. I saved around $3.50 compared to buying the same tube from my local auto parts store.

Various Applications

Permatex makes gasket sealant you can trust. For areas of my motorcycle’s engine where gaskets aren’t available, I tried Permatex Motoseal Ultra Grey. The engine case halves and the cylinder tops needed to be sealed, especially since they’d be exposed to oil all the time. I even contacted Permatex to make sure it was suitable.

I also used Permatex Ultra Grey for sealing differential covers on my Jeep. It works great and effectively prevents any leaks, ensuring the proper functioning of the differential, where permatex the right stuff grey vs black is also a good option.

Recently, I changed the differential oil in my 2005 E450 6.8L Motorhome and couldn’t find any OEM or aftermarket gaskets. As a result, I had to use Permatex for the gasket. I usually use gaskets for differential fluid flushes because they make future maintenance easier. However, I had to use Permatex in this case, and I’m glad I did. I prefer grey this time, though I’ve used the black and blue options before.

Immediately Put the Cover Back On

I liked the grey variant because you don’t have to wait for it to “skin up” before you bolt it back on. You can apply the bead and put the cover back on right away. It’s important not to overtighten it initially, so I kept it finger tight and then applied about 3-5 ft lbs of torque.

On valve covers, I mostly use this for the cam end corners and back plugs (for Hondas) with the O-rings. Make sure you clean off any oil residue with brake cleaner or alcohol.