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2010 Forester is losing engine coolant

With a cold engine in my 2010 Forester (29,000 miles), the coolant level has dropped from “full” to “low” in the overflow reservoir over the last 8 months or so. The level was down at that time (8 mos. back) and I topped it off. There is no obvious coolant puddle on the driveway. There is a gurgling sound at tailpipes and the exhaust is very wet. I’m worried there is a cooling system leak into the engine. Overall I have not been happy with the service dept. at my dealer (bought the car used from him) and wondering if this is the type of diagnosis and repair that an independent shop could handle.

An independent mechanic probably could do it, but you should still have some warranty left, which means you’d probably have to go back to the dealer unless you want to pay for it yourself.

A gurgling sound at the tailpipes won’t be from your coolant loss, and neither is the wet tailpipe. The combustion process puts a lot of water in the tailpipe. You coolant loss is so small that it will be very difficult to find the source. If you carefully inspect the metal tubes at the end of each hose, you might see a tell tail trail left over from the evaporation of the weeping coolant. It also might be weeping around one of the freeze plugs.

Because it could be a drive train issue which you do have warrenty left, take it to the dealer ASAP and DO NOT let an independent deal with it first. Not that you can’t get reimbursed, but it’s a headache and a lot easier for the manufacturer to pay a dealer then cut you a check well after the fact.

Firstly, as Keith said, water vapor is a byproduct of combustion and your engine puts a lot of it into the tailpipe. Don’t worry about that moisture.

To answer your question, yes, an independant shop can definitely handle the analysis to determine whether or not you have any coolant entering your cylinders. The test is basic, called a “cylinder leakdown test”. Basically, the tech puts an air supply with a valve and gage into each spark plug hole, lets some pressurized air into the cylinder, and tests it to see if it holds. If it does, you’re good. If not, he’ll check for other signs of transfer between the cylinder and the coolant surrounding the cylinder, such as testing your coolant for evidence of hydrocarbons (a simple lab test).

Since you bought the car used and have lost faith in the dealership from where you bought it, I would recommend a reputable independantly owned and operated shop.

I should tell you up front that your coolant loss is minimal, ambient temperature does affect the level in the reservoir, and normally if there’s a passage between the water jacket and the cylinders operating problems will develop, specfically overheating. But it’s good that you’re paying attention to your fluids and checking anything that concerns you. You’re doing the right hing, even if everything turns out okay, which I suspect it will.

@thesamemountainbike a block test is what’s done to check for a cracked head/blown head gasket

A cylinder leakdown test would be to determine why a cylinder had low compression

@alust2013 is right

The dealer has a responsibility to the manufacturer to supply certified service that will correct this problem. There is no guarantee that any mythical Independent will do a better job, especially one that could cost OP lots of money down the road. And, going to him first could guarantee you may never see any help for any related problem. You are now on your own by choice, and it isn’t even our money, it’s OP’s.

When you have warrenty work done, is less about YOU knowing what is wrong and being responsible to fix it and more about managinging the outcome to your satisfaction at no cost. Can’t speak for your area, but around here, dealers live and die by their service departments. They over charge sometimes and they recomend unnecessary routine service often, but they get repairs right more often then the average independent. If it’s free, it’s a no brainer. All that being said, it is not normal to loose that much coolant over that time in a modern car with a functioning recovery system. That’s really all you need to know to get it fixed free.

db4960, a leakdonw test is used to determin whether or not there is a breech from a cylinder to the water jacket, and it can also find a burned valve, Bottom line, if the cylinder won’t hold pressure the head needs to come off to find out why…unless, of course, obvious signs such as combustion byproducts in the coolant or bubbles coming up out of the radiator fill hole can be evidenced. At that point you need to pull the head anyway. If the cylinders all hold pressure, that’s a pretty good sign that there’s no headgasket breech or crack…cracks are actually very rare in stock engines.

The is no such thing as a “block test” unless you consider NDI testing, which is radiographic, magnetic resonance, or dye penetrant testing. But that’s a whole 'nother subject.

@thesamemountainbike there is a block test and this is what you use. In fact this is the exact tool I use.

All of my colleagues (current and former) that have used these tools refer to the test as performing a “block test”

If the fluid turns yellow, you’ve got something along the lines of a cracked block or a blown head gasket.

This is the cylinder leakdown tester I use

I will agree that the cylinder leakdown tester can find a burned valve

Must be a regional difference. I’ve never heard the term “block test” before.
I stand behind my post, annd I support yours as well. The important points for the OP are that there are tests to determine if there is a cooling system leak “into the engine” (OP’s words, which, taken in context with the rest of the post I believe to mean the cylinder(s) and that any independant shop can do them.

Since there’s no comment on overheating, poor heater performance, or anything of that nature, I’m guessing the tests will come up negative, but I think the OP is smart to ask the question and would be smart to have it tested. .

That block test looks interesting, but I would like to see someone use it first hand before spending the money and time on it, till then, I prefer the leakdown test. if there is coolant leaking into the cylinders, then you will see bubble coming out of the coolant everytime.

Well, cozz, db is calling it a “block test”, and Snap On is calling it a “combustion leak test”. but where I’m from we’d call it a “lab test”. I suspect it’s just a regional thing. A rose by any other name.

I recall seeing or hearing about that dye gadget. As I recall, it tests for combustion products getting into the coolant. The theory would go I guess that if exhaust products are getting into the coolant, then there would necessarily be a way for coolant to escape into the exhaust steam. I wonder how it works? I guess the CO2 dissolving into the coolant would make it more acidic, and that’s what it tests for.

Guys, I don’t believe that any of these tests are going to find anything. This is a loss of about a cup every 8 months. My Nissan PU lost coolant at about twice that rate, I had to refill the overflow every 4 months from when it was brand new.

When I changed the factory coolant out at the recommended time, I refilled with Dexcool. A month later I found a bright orange trail that lead me to an oxide inclusion in the gooseneck, under the hose but just outside the clamp area. I cleaned it out and filled it with RTV, put the hose back on and haven’t lost a drop since.

I concur with @Keith, a cup every 8 months isn’t something to worry about. Or at least if that’s the worst thing you have to worry about, you are doing ok. Sometimes I notice some gradual lowering of the coolant level in my Corolla if I’ve recently changed the coolant, or had to do something that opened the cooling system. After a few months, the lowering stops. I’m thinking there is some dissolved air or something which gradually escapes which causes this.

@Cozzmo no one tool will give you all the answers
Sometimes several different tools and several different tests are required before you’re 100% sure what the problem is

If you are not under warranty repair I WOULD BE SURPRISED, AND DISAPPOINTED IN Subaru!

George, that’s actually a chemical reaction rather than a dye test. That’s one of the options I call a “lab test”.

A “dye test” I think of as being a colored liquid of an extremely low viscosity that propogates into fractures and/or small orafices to highlight the imperfection. Dye tests include efflourescing dyes as well as just colored fluids, and they can be done static, or the part heated, or even pressure differentials applied to the sides of the suspected crack/orafice. This type of examination is generally done on a cast part fully stripped of its associated components and cleaned.

I agree with you guys that the test results are highly likely to be negative. I agree that this sounds like regular condensation in the tail pipe. But I commend the OP for paying attention and asking teh question, and I did want to offer reassurance that there are tests that can ascertain that no problem exists.