How to Fill Up Your Coolant System

I normally don't do instructional videos but two of our viewers specifically ask me to talk about how to fill a cooling system. Welcome to Mercie J where compassion and craftsmanship come together. I'm Rick Smith.

So there's two things I want to start off with. Number one is safety. Do not open the cooling system with a warm engine. It can be very risky for very serious injury. So before you do anything on your cooling system, always make sure you are fully educated on everything you need to do to remain safe.

The next thing I want to talk about is, many vehicles are very similar to this caravan that I'm looking at right here or this is actually Town And Country. But the place that we fill the cooling system is actually lower than the hoses.

And so the challenge that we have is getting the system full without having air pockets in it. If we have air pockets it's kind of like you having an oven mitt with one finger missing. Your hand overall will stay nice and cool. But that one finger will get seriously burned.

Well, it's kind of the same thing on an engine. If we have an air pocket, we can seriously damage one part of the engine because it gets hotter than the rest. So with those two things out of the way, let's talk about the two different types of systems. We have a system that we would refer to as an overflow system. And then we have a system that's referred to as a surge tank system. So we'll talk about the overflow system first, because that's what's on this Town And Country.

So on an overflow system the tank that we have that stores the extra coolant, it doesn't have a pressure cap on it. It usually has some sort of flip cap, something just a little plastic thing and then we have a pressure cap either on the radiator, or on a fitting somewhere.

And so essentially we have kind of two different systems in there. We have what's in the overflow tank and then we have the pressurized part of the system which is on the car. And as the vehicle warms up and cools down, coolant transfers between those two systems.

So we're going to fill it right here at the radiator or wherever that pressure cap is at. We can top it off over here at the overflow tank but we're gonna fill it up here.

Now a couple of things. One is when we are here at the shop, we use something, and this particular one’s an air lift, and we actually pull the system under a vacuum, and then that removes all the air and then it sucks the fluid back in. Assuming you don't have that available to you, we're going to fill it here.

Sometimes a funnel that gets that fluid nice and high will be helpful. We can take and we can squeeze and release, squeeze and release hoses, and that will help burp out air bubbles out of the cooling system.

Then we're gonna run it. And anymore that burps out will keep topping it off, but we wanna watch the temperature gauge if there's no air pockets in the system, the temperature gauge will typically just go to half and stay there. If it's fluctuating around that's a good indication we haven't got all the air out.

The other thing that we can do is we can run the heater on high. If it's super hot when the temperature gauge is in the middle, that's a good indication that there's probably not much air there. If it's not heating out of your vent, then there's a good possibility that you have not got all the air out. So I'm gonna move the camera over now to a vehicle with a surge tank system.

OK, so now we're working on a Chevy Colorado with the surge tank. One of the first things you're gonna notice differently, is that the tank on the overflow type system, the tank only has one line coming off and then it's about the size of your finger.

If you have a surge tank you're going to have a pressure cap and you're going to have multiple lines. This one has a couple of little lines, one little bit bigger line, and they can vary in size dramatically. So that's the main difference between the systems.

You're gonna fill them up about the same way. You're gonna fill up to where the pressure cap is at and you're gonna go through the same processes that I talked about on the overflow system.

The difference here is not gonna actually end up having a secondary tank to top off. So I hope this has been informational to you. And I just want to reiterate, I caution people to be very careful about safety and the potential for engine damage. Make sure that you're 100% when you fill your cooling system. If not, I really recommend you take it to a professional.

Thanks for watching, until next time, safe travels and blessings to you.

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