To use sealant or not? Water pump installation


I am attempting my first DIY water pump + timing belt installation. I already have everything apart. The vehicle is a 2000 KIA SPORTAGE EX.

The water pump that came with a paper gasket and the instruction sheet that came with it is a bit vague on regards with sealants and the KIA repair manual doesn’t mention anything about it.

Some say to use a sealant on both sides of a paper gasket when installing a water pump. Some people say to use only on the pump side. Some say to not use any at all. Which is it?

Also if you indeed need a sealant… what sealant should I use?

On the thermostat housing and the water pump that was already in the car, it was coated with some black rubber material. I assume this is silicone. This rubber material actually fell apart and it was just hanging inside the housing which doesn’t look like a good thing at all. This is the reason why I wanted to find out if I have to use sealants when using paper gaskets. Hope you guys can help me out.


This is the product that you saw on the original thermostat housing and water pump.

Manufacturers are getting away from using gaskets wherever possible.


Hello Tester,

I forgot to add that the housing and the waterpump had with their own gaskets when I removed them. The water pump had a paper gasket.

So should I be using “The right stuff” along with the new paper gaskets that came with the kit?

The Right Stuff requires no gasket.

That’s why I’ve used it for over 20 years.


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try to put a even amount all around and dont leave any gaps

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I replaced the water pump on my Corolla recently, used something similar to what Tester mentions, a spray-on gasket sealer, but IIRC it wasn’t a Permatex product. I think it was a Lock-Tite product,. red, not black. On the Corolla the water pump attaches to the engine and inlet pipe w/O-rings, not gaskets, so no sealer for those two interfaces. But the water pump itself it a clamshell arrangement, and I only replaced one-half of the clam, the side w/the moving parts. I re-used the other half. So I had to attach the two parts together using the gasket. I sprayed both side of the gasket as well as the mating surfaces. I just followed the product’s instructions. No leaks.

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I use permatex silicone on paper gaskets in contact with water or oil. I use a really light coat on both sides of the gasket. It may not be needed, but it helps hold the gasket in place and doesn’t hurt. Just don’t gob it on there where it squishes out the sides much.

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I might be out of date but I always used the red stuff on the gasket. Just means when you do it again you have scrape the stuff off. Actually I also used a light coat on the threads of the bolts to prevent seizing. Before they had the anti stuff.

I prefer using a normal gasket made of gasket material over the form-a-gasket. The silicon gaskets used in the manufacturing process is applied using precision robotics. I’ve used the form–a-gasket in the past with mixed results. It’s something you have to practice with to be good at it.

Red stuff is high temp, black is for contact with oil, blue is for contact with…gas, maybe? I don’t remember, those may not be correct, but it used to state it on the tube.

I keep a tube of black around for sealing differentials. Haven’t used a gasket on differential covers in years. Have never had a leak.

I meant the red gasket sealer in a little 4 oz can with a brush. Permatex or Napa etc. Used it on small engine block gasket too prone to leakage. Only problem is scraping the old stuff off the second time depending on access.

So many suggestions… The other thing is that I do not know what does “red, blue black” sealer mean. This is my first timing belt/water pump replacement and Permatex has so many of these sealants.

I bought “The Right Stuff” Black and Permatex High Tack Gasket Sealant.

Now I just learned that Permatex has something called “Water pump and thermostat housing”, an RTV silicone that can be used as gasket maker or dressing.

Like I said, I may be out of date but I used the first stuff if I had a gasket. I suppose the pros throw the gasket away and use the other stuff but for me, if it had a gasket, I just coat both sides of the gasket before assembly. A little leery of not using a gasket if one was supplied.


I had to do that job on the half of old part I retained, as part of my Corolla water pump replacement. It was pretty time consuming. Took close to an hour of tedious work. Have to be very careful not to nick the metal surfaces. I’d guess pro mechanics would just to buy the entire replacement pump, both parts already bolted together and leak-tested.

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I usually use the permatex high tack on the waterpump side to hold the gasket in place and use Permatex® Water Pump & Thermostat RTV Silicone Gasket Maker on the side of the engine. but you can just use the RTV silicone or the right stuff by itself like Tester said.

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Use either one with the gasket. The gasket is probably fine by itself, but either one of those you posted will help hold it on when assembling and provide a little “leak insurance”.

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I don’t go by color, especially across vendors. I read the datasheet, back of the packaging, or back of the tube to see what the temperature ratings are.

Permatex red usually has “high temp” written on the tube. Blue has “water pump” and/or “sensor safe” or some such written on the label. I don’t go by color either, really. I just read the label. Apparently Permatex kind of goes by a color coding of sorts, though. I agree, I wouldn’t just assume all red silicone is the same, for example.

Silicone materials will have a significantly wider use band for temperature than most other polymer materials. I was thinking about that difference as opposed to the difference in silicones.

Eh, ok. I just read the label. That’s pretty much the extent of my silicone knowledge :man_shrugging:

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