General Question

MissAnthrope's avatar

Regarding car coolant: is it a big deal to mix (add new on top of old), since I don't know what brand/type of coolant was last put in the car?

Asked by MissAnthrope (21491points) July 25th, 2011

I just noticed I’m seriously low on coolant and I would like to rectify this situation ASAP. I was reading my car manual and it says to not mix coolant types. I don’t know what kind of coolant is in there now, but really, it’s very low, so there isn’t too much of it.

I can’t figure out the diagram in the manual that shows where the drain plug is (yes, lame), so I’m tempted to just top it off with new coolant.

People who are mechanically-inclined: how serious would this be? Really bad idea? Moderately bad idea? No biggie at all?

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24 Answers

YoBob's avatar

I thought pretty much all of them are polyethylene glycol.

Follow the manual for sure, but in general coolant is coolant.

woodcutter's avatar

As long as it’s the same form of coolant I don’t think it matters. When the service guy adds it to a car’s cooling system he has now way of knowing exactly what brand is in there already. Different makes of cars use different formulas so as long as they match it will be OK

MissAnthrope's avatar

Okay.. that was kind of my line of thinking, as well.. that they should be similar enough and also that when a mechanic tops it off, he has no way of knowing unless he’s your regular guy. I just didn’t know if, like, I was unaware of something that might be a serious problem in terms of mixing.

The diagram is very vague.. it shows a small close-up area of the car where the plug is, but no legend to let you know what part of the car it’s talking about. I stood there for like 10 minutes comparing various car parts and trying to match it with the diagram. Sheesh.

I’m pretty tempted to just fill it up, since there is such a low level in there now. Thanks!

Adirondackwannabe's avatar

I think the first two answers are right on the types. The drain plug should be on the back of the radiator at the very bottom. They used to turn the opposite of all other plugs, counterclockwise instead of clockwise.

woodcutter's avatar

It depend how old the car is. Some cars use orange coolant, some use green, mainly I think for corrosion protection due to different materials in the system’s make up. There is also the type that is for “all cars” so that would be the default brand to fall back on. Is there a NAPA or some other parts place to call?

MissAnthrope's avatar

Yeah, I could try that. I also (newly) have a couple of guys that seem to be pretty handy that I can ask, I guess. I can’t afford a new car, so definitely not trying to mess this one up. What’s in there is greenish.. definitely not orange.

As a complete aside, why different types? Why’s it gotta be so complicated?

Russell_D_SpacePoet's avatar

Just don’t mix the pinkish/reddish looking coolant with the green coolant. Otherwise you should be ok.

Bagardbilla's avatar

S T O P !!!!!!!!!!!!!
don’t do that!
You’re going to put your Car dealer out of business! It’s people like you, who totally ingnore the manual, do not want to pay three to five times more for something you can get Auto part store for far less… Just think of all the poor car salesmen for sake of sanity my good lady.

ah, you’re good! Don’t worry. :)

also, what @Russell D Spacepoet said… Good call.

woodcutter's avatar

The next question is, why is it low now?

MissAnthrope's avatar

@Bagardbilla – Hee. Yeah, screw paying people to do stuff I can do myself for 5 times less.

@woodcutter – I am not so good at remembering little things like checking my fluids. I know, it’s so elementary and there’s no excuse. I do realize this. However, I am infamous amongst those who know me for being a bit of a ditz and I forget things. That’s what I do.

Anyway, my car burns a bit of oil, which the mechanic said wasn’t a big deal at this point since it’s not a lot. So, basically, I haven’t had an oil change in forever. Please stop yelling at me. I know, I know, I know. That is on my list of things to do soon. I have someone in my life right now who is helping me, setting deadlines and getting my ass on track to take care of the little things I always forget or put off.

So.. no oil change, no checking fluids, no one to tell me I’m low or top them off for me. I knew I was due for more oil, so I popped the hood to replenish that and took at peek into the various tanks to make sure all was okay.

MissAnthrope's avatar

Uh oh.. 3 people composing at once. I’m gonna get it, I can tell.

gasman's avatar

@YoBob I think you mean ethylene glycol, poisonous to people and pets. Polyethylene glycol is commonly prescribed as a laxative.

YoBob's avatar

Wow, you learn something new every day. I had no idea that there were incompatible types of coolant.

Here is some additional info if you are interested.

YoBob's avatar

@gasman – So far I am batting 1000 on this thread… ;)

woodcutter's avatar

@MissAnthrope You may want to check it out for any leaks. Sure sometimes it can just get low but if it’s been eons since you checked under there there is no way of knowing if it is that, or has a leak recently developed and it will leak down again? Worst case scenario would be blown head gasket(s) big bucks to fix.

MissAnthrope's avatar

Thanks so much, guys! I have to run for now!

WestRiverrat's avatar

As a stop gap measure, you can get away with adding just water until the next time you get the oil changed. Then have whoever changes the oil check the coolant. They will get the mix right for you.

Just add the water to the car with a cold engine. If you add it after running the car you could cause damage.

cockswain's avatar

@Russell_D_SpacePoet Why can’t you mix pink and green?

gasman's avatar

I also never heard of (or saw) orange coolant, but here what wikipedia has to say:

Certain cars are built with organic acid technology (OAT) antifreeze (e.g., DEX-COOL[15])...DEX-COOL specifically has caused controversy. Litigation has linked it with intake manifold gasket failures in General Motors’ (GM’s) 3.1L and 3.4L engines, and with other failures in 3.8L and 4.3L engines. Class action lawsuits were registered in several states, and in Canada, to address some of these claims.

From @YoBob‘s link, when you mix green and orange:

The coolants chemically react and form a gel rather than a liquid. The coolant stops flowing through the system, clogs up coolant passageways and water jackets, radiators, and heater cores. The water pump overheats and fails due to a lack of lubricant in the coolant. Head gaskets blow, heads warp, and the engine suffers major damage.

cockswain's avatar

Whoa. Mixing colors is bad.

woodcutter's avatar

@WestRiverrat I have done that soooo many times. One just needs to be aware they have diluted the water/ coolant ratio so during the winter it may be risky. But it will get you to the garage.

snowberry's avatar

It depends on the make of the car. As I recall my daughter’s VW has to use a specialized coolant. Of course it’s only to be provided by the dealer. And no, you’re not supposed to mix theirs with the store brand.

Adirondackwannabe's avatar

@MissAnthrope Just volunteering to check your fluids anytime.

MissAnthrope's avatar

Heh heh. Heh. Heh.

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