2015 CX-5 GT With Blown Head Gasket...Advice Needed

[anyman]

It's always burned about 1/2 qt of oil every 5k miles. This started at maybe 30k and has held constant.

I've checked the water pump. I have a bit of the classic "weeping" residue from the weep hole but no crusting or anything. I've yet to FULLY examine the engine block but from the places I can see, there's zero evidence of coolant seepage. This engine is bone dry on the outside.

As far as coolant entering the combustion chamber...no misfires. Car drives perfectly fine. Negative block test but I realize those aren't exactly accurate. No constant bubbling in coolant funnel but did have SOME bubbling while trying to burp the system after doing the block test (you have to remove a fair amount of coolant in order to do the block test so I'm sure I introduced some air into the system).

I really wish I had tracked the coolant closer beforehand. I spoke to a shop and they said when it leaks this slowly it could be a needle in a haystack situation. It's almost like it needs to get worse before they can give a better diagnosis. But I also don't want to wait until something catastrophic happens.

 

[madar]

It's always burned about 1/2 qt of oil every 5k miles. This started at maybe 30k and has held constant.

I've checked the water pump. I have a bit of the classic "weeping" residue from the weep hole but no crusting or anything. I've yet to FULLY examine the engine block but from the places I can see, there's zero evidence of coolant seepage. This engine is bone dry on the outside.

As far as coolant entering the combustion chamber...no misfires. Car drives perfectly fine. Negative block test but I realize those aren't exactly accurate. No constant bubbling in coolant funnel but did have SOME bubbling while trying to burp the system after doing the block test (you have to remove a fair amount of coolant in order to do the block test so I'm sure I introduced some air into the system).

I really wish I had tracked the coolant closer beforehand. I spoke to a shop and they said when it leaks this slowly it could be a needle in a haystack situation. It's almost like it needs to get worse before they can give a better diagnosis. But I also don't want to wait until something catastrophic happens.

That's over half a quart. Do you see oil floating in the antifreeze at the reservoir opening?

 

[anyman]

What's over half a quart? The oil burning? No, it has consistently burned 1/2 qt for the majority of its life.

Reservoir is clean. When I did a block test I took the opportunity to examine the coolant I had to remove and no surface sheen. Reservoir has no signs of oil/film residue.

 

[edmaz]

We had already decided on a new car this year due to my wife's new job that requires her to travel quite a bit as well as a growing family. So regardless of what we do, the CX5 won't be ours for much longer but I don't want to regret being passive about this.

.... I But I also don't want to wait until something catastrophic happens.

A head gasket job would be exactly the same amount of work (i.e. $$$), regardless of whether it's a pinhole leak, or if the gasket actually blows (presuming of course that the vehicle doesn't continue to be driven with a badly blown HG). So I don't think 'catastrophic' is a real concern in your situation. The key is for you keep closely monitoring the rate of coolant loss, because that's what will tell you if the leak is getting progressively worse or not.

Given your plan to get rid of this vehicle soon, IMO the best option is to just keep monitoring the level and top off when necessary, unless it gets worse (which may very well not happen). That of course is your choice however, be advised that a HG job will be minimum of 1K, and likely quite a bit more than that.

If you feel compelled to do 'something' then, given all of the particulars of your vehicle, it could likely be a perfect candidate for trying one of the stop-leak products. If that's something you might consider doing, you would definitely want to temporarily bypass the heater core (and possibly the radiator as well), because you don't want to create a brand new problem by gumming that up.

 

[madar]

What's over half a quart? The oil burning? No, it has consistently burned 1/2 qt for the majority of its life.

Reservoir is clean. When I did a block test I took the opportunity to examine the coolant I had to remove and no surface sheen. Reservoir has no signs of oil/film residue.

Sorry, didn't reference the right post. You adding 24 ounces of coolant in a six month period is over half a quart. The other things you could do or have done is a compression test and a cooling system pressure test.

 

[anyman]

@edmaz Thanks for the response. I'm assuming a head gasket job is going to be $3k+ with the rates shops are charging and most wouldn't even give me a ballpark which is frustrating. One dealer quoted me about $2500 bare minimum.

I'm going to take the advice of everybody and monitor usage. I've been doing it closely for the past couple of months anyway. Change the oil every 3k as well.

@madar No worries. That's a rough guess as I didn't closely monitor the usage for the first 2k since the previous oil change. I'll have more accurate data from January onward.

I think paying $200 for a diagnosis is money well spent at this point. I'd insist on both cooling and compression test to help rule out a head gasket.

I think we'll probably end up in a new vehicle in the next month or two to be honest. It would be nice if this car could go another couple of months until we get that replacement vehicle. Then I would have all the time in the world to figure out next steps vs. feeling rushed to do something now.

 

[sm1ke]

Personally I wouldn't even bother with paying $200 for a diagnosis. If you're getting rid of the car that soon, just top up as needed until you sell it/trade it in. Chances are probably very low that something related to this consumption would suddenly turn into a major issue or leave you stranded.

My 2018 CX-9 with the turbo 2.5L has been consuming small amounts of coolant. I usually top up every couple of years or so. I first noticed the issue when a used oil analysis showed elevated levels of potassium. I had the dealership check for leaks, pressure test the system, and then check for leaks again. They couldn't find any leaks or any signs of a leak. So, I just change the oil on a regular basis (every 7k kms or 4.4k mi) and top up the coolant if it gets low.

 

[anyman]

@sm1ke Wow, interesting to hear. How long have you had this issue of losing coolant?

 

[7eregrine]

Yep, this isn't some specialty exotic car.

Like a freaking Volvo. If you replace the battery you need a dealer or someone with VIDA software connect to the car to TELL it it has a new battery. I wish I was joking. It will work if you don't but not as well.

 

[anyman]

Thanks again for all of the replies. After consulting with a few shops and looking at what you all have said, it sounds like this is more of a wait-and-see situation. One shop said that if it's losing that little coolant then they may find nothing during the diagnostic. And he echoed what @Snorting2.5 said in that the issue could very well have been happening for a long time and is just holding steady. So even if I wanted to repair it, it wouldn't be wise to do it at this point because finding the exact cause wouldn't be readily apparent with such a slow leak. If anything changes I'll update this thread.

 

[Snorting2.5]

It's always burned about 1/2 qt of oil every 5k miles.

use thicker oil. it will stop consuming.

 

[Snorting2.5]

Thanks again for all of the replies. After consulting with a few shops and looking at what you all have said, it sounds like this is more of a wait-and-see situation. One shop said that if it's losing that little coolant then they may find nothing during the diagnostic. And he echoed what @Snorting2.5 said in that the issue could very well have been happening for a long time and is just holding steady. So even if I wanted to repair it, it wouldn't be wise to do it at this point because finding the exact cause wouldn't be readily apparent with such a slow leak. If anything changes I'll update this thread.

repairing it would be a costly gamble of tearing down the engine and rebuilding the seals.

your best bet is to just use thicker oil.

my 2.5 went from fairly high oil consumption to zero after permanently switching away from 0w20

it always consumed some coolant. now, it barely consumes anything at all. i'd say that's your "fix."

try 5w40

 

[anyman]

Yeah, the few estimates I could shake out of some mechanics were in the range of $2-3k...one quoted $7k!!! But I think he didn't want the job and argued Subarus are cheaper to do head gaskets on...which I've always heard the exact opposite.

 

[sm1ke]

@sm1ke Wow, interesting to hear. How long have you had this issue of losing coolant?

Probably since 2020 or 2021? It's never caused any issues, and if I hadn't been getting the oil analyzed I'd be none the wiser.