Need to Replace a Gasket on Your Car or Truck Sue Has Some Tips for You

Look at all these gaskets, why are they here? And what do they do? I'm going to tell you about it. This is Sue from 1A Auto.

So, here are all different types of gaskets for cars. Don't think it's a boring subject, because it can be but it's really important and you need to know a lot about this stuff. You can't just whimsically throw a gasket in and then add some RTV and think it's good, because it's not. First mistake a lot of people make is a paper gasket. This is for, like, an IAC valve, which is idle air control valve, goes on the throttle body. Never put RTV on this. It's impossible. But if you have a paper gasket for water pumps, oil pans, intake, I see this for years, people put RTV on the gasket thinking, "Oh, it's gonna stick it even better. It won't leak." It's the worst thing you could do. RTV, room temperature vulcanizing, came up with that. But that's what it stands for, RTV. It destroys paper gaskets and it will expand rubber. Rubber comes in a flexible form, but it's still got a tautness to it, right? You add this stuff to it, over time, softens up.

So I want to just go quickly over different types of gaskets that's in your engine. Whether it's truck, car, it doesn't matter. So what we have here is a section of, like, EGR, which aren't in a lot of newer cars, but in the older cars, they were. And they're a combination of paper and metal. And the reason for that is because it's an exhaust EGRs for emissions. So it has the heat of the exhaust on it but yet it's mounted to an intake, which is usually aluminum or cast steel if it's an older car. So it has to have the different type of temperature and flexibility. You put straight paper like this IAC valve on an EGR and it's gonna cook and just blow right out. So it has to have the flexibility for heat and cooling at the same time.

Then you have rubber seals like thermostat. This has base for it so that when it reaches coolant, coolant touches it, it doesn't expand, it doesn't flex and just goo all over the place. It's supposed to be a solvent base rubber seal that can handle coolant and the petroleums that are in coolant and stuff. Same with a valve cover gasket. It's rubber, but it has the ability to handle the oil base. And the temperature stuff, a lot goes into gaskets that people don't really think about. They're like, "It's just a gasket." Well, it's not just a gasket. This engineering has to be technical in order to deal with where it is in the car, temperature, what kind of fluid's gonna touch it, and flexibility.

Exhaust gaskets come in different forms also. You've got the flat metal, okay? Which it has a solid ring in and then a compressed, like, these little dots, like a golf ball. And that's actually to disperse probably the heat in that metal gasket. So it's not a solid because this is right on the exhaust pipe where it is the hottest. Well, the manifold is the hottest, but it just disperses the actual temperature. Then you have wound metal with a carbon coating on it. These are really good for cone-shaped exhaust pipes. The flat one has the same metal ring in the center, but folded carbon paper that has a metallic feel to it. Then you have your solid metal, which usually is straight manifold ahead. And those actually never go bad. You can reuse these. As long as that exhaust has not pitted or cracked this metal, you can always clean it up with a solvent or light sand scuffing, paper sander, and then put it back on. If you don't get the proper gasket with the part you're replacing it with. As long as it fits bolt-wise, I would use the factory one as long as it's in good shape.

Thermostats, like I said, you have the coolant solvent for the rubber, old type was paper, or is a flat cone head went down on the intake and you put your thermostat in there, and maybe some of you remember these, but they peel. They had a sticky side to them. I remember when they didn't have a sticky side and they came out with it and I was like, "That's the greatest idea ever." Because you could stick this to the housing and slide it down through the intake and the gasket didn't fall off. But a lot of people made mistakes and added RTV to this and thought, "Oh awesome. This is gonna work." That way it definitely doesn't slide off. And would last six months, if that coolant shooting out everywhere is because it tore up the paper. It doesn't work. Don't mix the two.

So here is the top three RTVs that I would use in my shop. Don't mind the chicken scratch, I'm not a teacher. But I did put down the quick ranges of temperature. Obviously, Fahrenheit's 65 to 650, that's exhaust. That's really high temp exhaust. Flexible for uneven surfaces would be the gray, you got 350 to 400 Fahrenheit, which is like an engine block, right? It's a constant state temperature once it reaches that, and it's an uneven oil pan intake to engine block. Then we have temp 65 to 500, which is oil resistant, which is a good one for oil pans again, timing chain covers.

Don't forget joint compound. You just need a little bit of it. A lot of mistake people make with RTV is they overcompensate. They think, "I'm gonna add extra amount because then it will definitely seal." Well, it actually makes a huge mess. And don't forget an oil pan. When you put that up, if you see a lip coming out on the outside and it's dripping, it's doing the same on the inside. So, a nice bead, follow directions on the back of the actual instructions for RTV that comes with, usually says an eighth of an inch or quarter-inch bead and go around the item, place it up and torque it, can't say that enough. So, the other kind of gaskets are rubber gaskets, which are O-rings, valve cover gaskets, clean it up, place it back in the valve cover. If it has not been contaminated and expanded, it'll actually seal. It will reseal and you don't have to reuse it so you can save yourself some money that way too.

So if you're doing a valve cover only because you're taking it off to do something inside, check out the condition of it. If you bought one, that's great. You're ready to use it if you need to. But if it's in great shape, there's not oil, like, resistant and it's over the size when you put it in the valve cover, then reuse it. Just clean it up with a nice rag. Don't put a solvent on it. Don't spray it with parts cleaner and clean it that way because now you're gonna break down that rubber and it will end up leaking.

So, another quick thing I wanna talk about is how you diagnose if your gasket's bad. So, obviously, if you have a leak. Thermostat, type of gasket, shall I say, whether it's O-ring or paper, you could cool the system down, put a coolant pressure test around there, and see if it's shooting out where the surfaces and the gasket meets. Obviously, you're gonna check the surface for pitting, whether it's a thermostat housing which is plastic nowadays, see if it's cracked and might just be the gasket. That's one way.

Another way is, like, intakes. People have engine coats come on and you can say, "Oh, it's running lean or running rich." And you have an idle that fluctuates up and down. That means you have a vacuum leak somewhere. So, that usually is going to be a rubber O-ring style. Now, I learned a quick way to do this if you don't have, like, a smoke machine or actual vacuum leak finder, you can let the engine cool down because it expands when it gets hot and it will actually stop the leak. So, engine cold, really cold, bubbled water in a can spray it, soapy water put it all over the intake area or even exhaust, this works too. And then start the car up.

Wherever there's a leak it's just like air blowing into a balloon, the bubbles will just shoot right out and you'll see it actually come out of the rubber gasket where a plastic intake meets an aluminum block. The rubber O-ring could be contaminated from just even a little bit of oil leak out of the valve cover. Just hitting the same spot, the rubber will start to expand and you'll have vacuum leak coming right out of there.

Intake, now we wanna talk about intakes. These are a big repair. A lot of people do them and it's great if they do them and they're successful at it but because you have to be a little patient and have some good technical thought about what you're doing. It's not a matter of just throwing it in and cranking down on bolts. Everything's got some finesse to it.

You need some finesse. Because see this gasket, this is a plastic gasket with a rubber seal embedded in it. It's made like that at the factory. These bolt holes and these edges right here are formed to go under a certain torque spec. So you really need to torque an intake. I mean, you need to torque everything. But if you're not a Torquer, you're someone that doesn't like to do a lot of torquing on their car, this is the one most important, other than your wheels or brakes, just make a list of it. But you will destroy the running and condition of your vehicle, if you do not torque the intake. So, this is another compound joint where it's gonna be moving, it's where the intake meets the top of the head and the block.

So you would put in there what I would call a...not the orange that's high temp, that's for like exhaust. I would use the gray or the black silicone base because it's got oil resistant and it's good for flexible. The gray is good for flex. A lot of manufacturers from the factory will do the gray on oil pans and actual intakes. That's because of the flexibility. So, just do a quick research before you purchase it, make sure you put the right silicone RTV with the right gasket, and then you should have confidence driving your vehicle down the road and not have to worry about doing that repair twice.

So hopefully, you learned a few things or maybe you have something to add to it, put it in the comments down below. And if you're not a subscriber, please subscribe. And don't forget to ring that bell, it turns on all your notifications so you don't miss any future videos.