Product Review - Permatex Ultra Grey RTV

[Snagglefoot]

There are a lot of ways to seal a water pump to an engine block:

- fiber gasket with no sealant
- fiber gasket with sealer on one side
- fiber gasket with sealant on both sides

Then there are " Form-a-gaskets "

- " Right Stuff" instant gasket from Permatex that you bolt together right after applying, then put into use
- RTV's of which there are a large number of variations that you use to make the gasket but need a day or so to set up.

I wanted to try a "form-a-gasket". Permatex pushes " The Right Stuff " as their premier product. It is 10 times thicker than their RTV and you can put the vehicle back into use right after you bolt it up. However, it's also the most expensive (about $15 U.S. for a mini cartridge).

In a moment of cheapness I decided to buy a squeeze tube of Permatex Ultra Grey. It's advertised for use in many applications where the bolts are torqued down with a lot of torque such as with water pumps. It requires a full day to set. The cost was about $7 US. Obviously these products aren't great in a pro shop because you have to wait overnight for them to set.

I used the installation process on the back of the tube which is to run a 1/8 diameter bead along the sealing surface, making sure to go completely around the bolt holes. I then tightened the bolts finger tight and left it for one hour.

However, I found out that it did not skim very well and would smear when touched, so I left it for an additional hour. I believe the reason was, the product requires humidity to set and my heated garage (68 F) had a very low humidity. I then to tightened down the bolts to 50% torque. The instructions said to take it to full torque but I noticed it oozed in a few places so I stopped tightening. I let it sit for one more hour and then tightened it to full torque with no more oozing.

I emailed the tech folks at Permatex and they said I did fine, and that I was right to wait longer in a low humidity environment. They also said a small amount of oozing was OK. They also said my bead installation in the photograph was just fine. There was one spot I feel was too thin but in turned out OK and sealed.

After bolting up, I was supposed to leave it for 24 hours, but I left it for 40 hours because of the low humidity. Overall, not much was squeezed beyond the flange and what did was very tough. The product held and the car is back in service. If I was was to do another form-a-gasket I would use "The Right Stuff" to avoid the waiting time. Enjoy the photos.

 

[SZR48207]

Thanks for sacrificing your time to test this out, but man I'd rather go buy a OEM gasket than have to wait almost 2 days to know if the seal was any good!

 

[Snagglefoot]

Here is a mini-cartridge of "The Right Stuff " that I think might be better.

 

[Jimzz]

wow you use a lot of RTV on that pump.

I prefer to use a very small amount of Ultra RTV on both sides if it has a paper gasket; metal or rubber gaskets go on clean and dry though.

 

[WobblyElvis]

You really went to town on this job and I'm glad it worked out well for you. I know you were following the correct instructions but I usually use less than half that mount of sealant. If the pieces are bolted together and almost touching [perhaps .002" apart] I can't see much sealant being needed. Just my two cents.

 

[double vanos]

Pretty much my experience with the gray stuff for diff covers. It's formulated to resist the additives in hypoid oil. Same directions, followed them to the letter. Filled the diff 24 hrs later and it's all good. Nice bead sticking out from the cover, uniform all the way around. Hardest thing is getting the gasket surfaces 100% clean to ensure a good bond.

 

[Chris142]

I use the ultra grey exclusively. It may be soft on the outside but the area where it seals will be dried or drying. I have never let it sit longer than an hour and never a leak. It's on every differential cover I have.

 

[BigD1]

No way I would use that stuff on a water pump. Last time I did a head gasket job the cylinder head water jackets were clogged with RTV.

Gasket with High Tack or Gasgacinch is all I need for a water pump.

 

[WyrTwister]

Watching youtube mechanics , I have seen both products used .

I tend to use the traditional gaskets + sealant between the replacement part and gasket . This keeps the gasket in place while I position the part and start the fasteners .

I use the sealant on the part , instead of on the engine , so that if I ever have to replace the part , at a latter date , I do not have to do very much ( if any ) scraping . The gasket , sealant & old part all go into the dumpster together .

And I do not have to fight the sealant to separate an old part from the engine . They are not " glued " together .

I use the black Permatex non hardening product . # 2 , I think .

 

[nthach]

Permatex Ultra Gray is a clone of the ThreeBond stuff the Japanese OEMs use - it matches the color of HondaBond, and Nissan/Subaru RTV. Toyota also uses gray, but black ThreeBond 1207B at the dealership. It's also OEM specified as a substitute if the OEM-spec HondaBond/Fujibond/Nissan RTV/Toyota FIPG isn't available(Toyota is an oddity calling for a special, esoteric ThreeBond 1282B RTV for sealing areas that will see coolant, but no dealer tech or mechanic uses it, the common black stuff works fine there).

I'd use it, but I've learned from Trav here that a thin bead is all you need.

 

[Yah-Tah-Hey]

Originally Posted by Snagglefoot
There are a lot of ways to seal a water pump to an engine block:

- fiber gasket with no sealant
- fiber gasket with sealer on one side
- fiber gasket with sealant on both sides

Then there are " Form-a-gaskets "

- " Right Stuff" instant gasket from Permatex that you bolt together right after applying, then put into use
- RTV's of which there are a large number of variations that you use to make the gasket but need a day or so to set up.

I wanted to try a "form-a-gasket". Permatex pushes " The Right Stuff " as their premier product. It is 10 times thicker than their RTV and you can put the vehicle back into use right after you bolt it up. However, it's also the most expensive (about $15 U.S. for a mini cartridge).

In a moment of cheapness I decided to buy a squeeze tube of Permatex Ultra Grey. It's advertised for use in many applications where the bolts are torqued down with a lot of torque such as with water pumps. It requires a full day to set. The cost was about $7 US. Obviously these products aren't great in a pro shop because you have to wait overnight for them to set.

I used the installation process on the back of the tube which is to run a 1/8 diameter bead along the sealing surface, making sure to go completely around the bolt holes. I then tightened the bolts finger tight and left it for one hour.

However, I found out that it did not skim very well and would smear when touched, so I left it for an additional hour. I believe the reason was, the product requires humidity to set and my heated garage (68 F) had a very low humidity. I then to tightened down the bolts to 50% torque. The instructions said to take it to full torque but I noticed it oozed in a few places so I stopped tightening. I let it sit for one more hour and then tightened it to full torque with no more oozing.

I emailed the tech folks at Permatex and they said I did fine, and that I was right to wait longer in a low humidity environment. They also said a small amount of oozing was OK. They also said my bead installation in the photograph was just fine. There was one spot I feel was too thin but in turned out OK and sealed.

After bolting up, I was supposed to leave it for 24 hours, but I left it for 40 hours because of the low humidity. Overall, not much was squeezed beyond the flange and what did was very tough. The product held and the car is back in service. If I was was to do another form-a-gasket I would use "The Right Stuff" to avoid the waiting time. Enjoy the photos.

Hey there Snaggle, an eighth inch bead would have sufficed. I would be concerned with gobs of that sealant showing up in internal coolant passageways. That excess sealant had to go somewhere.

 

[zorobabel]

Originally Posted by Chris142
I use the ultra grey exclusively. It may be soft on the outside but the area where it seals will be dried or drying. I have never let it sit longer than an hour and never a leak. It's on every differential cover I have.

Do you use it in a metal to rubber scenario too?

 

[Snagglefoot]

Originally Posted by Yah-Tah-Hey
Originally Posted by Snagglefoot
There are a lot of ways to seal a water pump to an engine block:

( content edited out )

I emailed the tech folks at Permatex and they said I did fine, and that I was right to wait longer in a low humidity environment. They also said a small amount of oozing was OK. They also said my bead installation in the photograph was just fine. There was one spot I feel was too thin but in turned out OK and sealed.

After bolting up, I was supposed to leave it for 24 hours, but I left it for 40 hours because of the low humidity. Overall, not much was squeezed beyond the flange and what did was very tough. The product held and the car is back in service. If I was was to do another form-a-gasket I would use "The Right Stuff" to avoid the waiting time. Enjoy the photos.

Hey there Snaggle, an eighth inch bead would have sufficed. I would be concerned with gobs of that sealant showing up in internal coolant passageways. That excess sealant had to go somewhere.


Hey Yah-Tah-Heh! Where the heck were you when my shaky hands were trying lay the bead? Yes, I think I would go thinner next time. For scale the width of the skinniest part of the flange was .31 inches. If the bead took up half the flange it would be .16 inches instead of .125. Anyway, I was thinking that I was supposed to wait an hour so the bead does not ooze out much after the initial finger tight mode. There is one short stretch on the flange where the bead got flatter ( by mistake). That would have been closer to 1/8".

 

[Snagglefoot]

Here's what I used for helping to clean the old gasket. It contains Dichloromethane and methanol so wear gloves and use in a ventilated area. It doesn't have a strong solvent smell but is a bad actor.

 

[StevieC]

I've used this on my Journey's transmission pan for the first ATF change and left it for a couple hours before refilling and it was fine 30K miles (50K KM) later. No leaks. I've speed cured this stuff with a heat gun on low moved around for 1/2 hour prior to letting it sit.

 

[krismoriah72]

Ive never used the Grey.....on water pumps always thought it was too flexible. Not sure why you didnt use their Waterpump and Thermostat Gasket maker?

"formulated specifically for water pumps and thermostat housings. Highest water-glycol resistance available in an RTV silicone."

https://www.permatex.com/products/g...ter-pump-thermostat-rtv-silicone-gasket/

I have used the Blue..its good for waterpumps and thermostats in autos and marine applications..

 

[Snagglefoot]

The tech at Permatetex told me Ultra Grey was a better product. There are numerous Permatex products that can be used on water pumps. Go to www.Permatex.com and take your pick.

They like " The Right Stuff " the best.

 

[Linctex]

I have had good success with various "Ultra" branded silicone sealers. I'll never go back to the inexpensive ones.

 

[nobb]

I always thought the Grey was for oils. They make a Blue for water pumps.

IMO I would only use an RTV for a water pump if a fiber gasket was not available. And even with a fiber gasket, I would use it dry. There is not a single gasket maker or OEM that recommends the use of a gasket with additional RTV....even if many seasoned mechanics do it and claim it works. The reason not to is because you'll get small chunks of hanging RTV that could break up and clog things. It's also a huge pain to remove and clean later.

The fiber gaskets do swell slightly after install to take up any loose tolerances. I did have in one instance a fiber gasket that leaked slightly even though everything was torqued properly. After about 2-3 months the leak stopped, of which I assumed is due to the swelling of the gasket.

 

[bmwpowere36m3]

I only use two RTVs, Permatex Ultra Grey and Ultra Black. Ultra Grey IMHO is for machined surfaces or components needing a "rigid" connection, i.e. diff covers, flanges, machined block/oil pan interface, etc. Usually I'll use Ultra Black or "Right Stuff" gasketed surfaces, as needed.

In addition Hylomar or anaerobic sealants as needed.