Maintenance Question: Engine Coolant/Radiator

What does the engine coolant reservoir supply coolant to? The engine directly or the radiator

I read someone uses the red coolant in the reservoir and the green coolant in the radiator. This way he know where the leak is from if there ever is one. I thought this was a clever idea.

But then realized it doesn’t make sense if it goes to the same place. Could someone clarify?

 

The reservoir supplies coolant to the radiator neck and cap. When there is negative pressure it sucks coolant out of the reservoir. When there is excessive pressure the cap will leak extra coolant into the reservoir.

DONT MIX - different colors frequently don't mix well and can cause clogs and other issues. There are at least 6 different types of coolant common in vehicles. Your engine is not compatible with all of them, and most of them can't mix with other types.
https://www.valvoline.com/our-products/antifreeze-products/antifreeze-education/engine-coolant

 

so just to confirm it all goes to the same place, ie if I pour coolant in the radiator cap or the revisor it all ends up in the radiator eventually.

thanks for the info btw!

 

Yes. However you always want to make sure the radiator is full first.

Remember NEVER open a hot radiator cap. You release that pressure and the coolant may suddenly boil violently and shoot burning hot coolant all over you. A liquid under pressure will raise it's boiling temperature. This is the entire reason there is a pressure cap.

Some GM vehicles and others have combined the reservoir with the main radiator and coolant passages so there is only only place to fill. That's fine. I believe Toyota still uses the tried and true (in true Toyota fashion) radiator, with pressure cap, and reservoir methods.

Also, note that the reservoir has a max fill line. This is on purpose to give the expected amount of expansion room when the engine is hot.

 

I would also like to add that factory fill coolant is SLLC type and is good for 5 years and about 100,000 miles. You know...the Pink stuff...
As I live in a temperate climate I have topped off my coolant bottle about a pint of distilled water over two years...
I suggest in a harsher climate (hotter/colder) that one use the SLLC oem stuff...
Hope all of the information here by others is helpful too however Don't Mix Different Types of Coolants.

 

Few years ago, had a Chevrolet minivan that ran the red coolant. While I was out of town working my brother in law added the green coolant to it. This let to the overheating and a blown head gasket. Upon inspecting the fluid had gummed to the consistency of peanut butter in the radiator (and almost the same color as peanut butter too). Mechanic said was due to mixing the coolant types

 

Yeah, Dexcool does not play well with others.

 

Thanks everyone, also good to know 5yr 100k. I’m at 30k lol.

getting to know my truck and first self maintenance I’ve ever done on my vehicles so was doing all my research and got a bit ahead of myself.

 

Clever ideas are not always good.

 

Not true. Never mix green and pink or red, yellow, blue, orange or any other colors. The tank is for expansion. when the engine is hot it keeps excess coolant in the tank. Once cold, it leaves the tank to prevent any voids in the system.

 

Color of coolant doesn't matter near as much as type. Read the label carefully. Not all green coolants are the same, many times people confuse red/pink with orange dexcool.

There is a green antifreeze that mixes fine with most others (bottle says all types but not sure I trust that)

CHECK YOUR OWNERS MANUAL FOR TYPE, THEN READ THE BOTTLES till you find one that shows its compatible.

 

Not true, maybe today there are some off brands making one size fits all type coolant, but for the most part color does matter.

In the 70's it was all green, in the 80's different makers had their own formulas.

Toyota was Red, GM was orange, Honda was Blue. Mix GM orange and Toyota Red, and you'll get mud.

As cars went from Brass radiators and cast iron engines, to Aluminum Rads & aluminum engines, they need better/different coolants. The colors were changed to help the consumer not mix different types.

Toyota's had pink for the last 20 years.