Hydrocarbons in coolant

Took car into the shop and they tested and found hydrocarbons in the coolant overflow, pressure tank, and a very miniscule amount in the radiator neck. They obviously said the head gaskets need to be replaced. I was just curious if there is any other way for hydrocarbons to make it into these places besides the head gaskets. Just curious. 06 2.5 GT btw.

What's the problem with the car?

 

Hydrocarbons can come from many places. They could come from a cracked head, a blown head gasket, cracked block, or even from traces of oil in the coolant from an oil cooler problem.

 

If you aren't having any problems with the car, flush out the cooling system and test it again. I've even seen old coolant cause a positive block test. Even a turbo problems potentially cause this.

No problems ATM actually. Just a check up. They tested and found hydrocarbons in the check up. Car is not over heating, and is running normal as far as I can tell. They said this is evidence the HG's are starting to fail internally. That's why I was curious if the hydrocarbons can get in there some other way. I plan on flushing the cooling system this week and retesting in a month or so?

Go with your plan and get back to us with a update, please.

 

Another way to check for a HG is if you see air bubbles in the overflow tank.

Took the car to different shop today to get the coolant flushed and a quote on some other werk. Tested for HC's again, and the guy at the shop didn't think it was HC's causing the mixture to turn from blue to green but actually a little bit of coolant being sucked up during the test, plus no bubbles in overflow or discoloration. He thought the last shop just didn't realize that a tiny bit of coolant was splashing up.

 

So fingers crossed on that one. Put off flushing the coolant until the other work is being completed since the car isn't over heating or anything and can just do everything at once. Plan on doing that and just testing again after a month or two.

I had bad head gaskets without oil in my coolant, coolant looked good and clean

How did you diagnose? Just overheating?

dealership did a test

either a compression test or pressure test though radiator idk what they did

 

my car's coolant gets super hot (needle gets 4 bars from red on temp gauge) when driven wot constantly, dealer says they cant reproduce the problem because thats not how your suppose to drive. yea bought a sporty car thats not suppose to be driven sporty. still gets super hot though...

 

they changed thermostat and told me maybe it needs a new radiator cap:iam:

FWIW, most honda's with bad HG's don't put coolant in the oil either. So just because you don't have coolant in the oil doesn't mean it's not a HG.

 

Any good repair shop can test the coolant system and tell you if it's leaking.

UG, and you had your hg's replaced and still all this? Honestly I'd think someone at the dealership would WANT to try and replicate the situation by driving

 

Well, since the car has no other symptoms, no over heating etc, I'm just going to continue on until it does and assume things are ok. I'm still going to get the coolant flushed and have the first shop test again just to see what they say though. Last shop said a compression test isn't any more accurate than the test the last two shops had completed.

Just to be safe I would pick up a gallon of coolant, I like Peak Global for like $15.00 and carry it with you.

 

I'm also thinking all systems will lose a little coolant over time. Water does evaperate over time.

I had a shop say the same thing at 80K, easy money for them. You will always have a little in the coolant, and my dealer told me that. My car went 165K and did not have a head gasket problem. They are full of sh!t.

Couldn't hydrocarbons come from rubber hoses deteriorating ever so slightly?

The shop is a pretty respectable Subaru shop locally so I don't think they bs'ed me about the results. I just don't think they realized how the results came to be maybe. I am going to have some coolant on me at all times just to be safe. I'm not sure if enough hc's could come from rubber hoses, have to be a very miniscule amount I'd think.

lccl, so it's been a few day's, how's the coolant level ?

I had 98 OBW that had a blown head gasket. When I took it to the dealer after it would over heat they just filled up the radiator. I friend worked for Toyota and let me borrow his hydrocarbon tester. When I did the test it showed hydrocarbons. I did have to replace both head gaskets and the bottom end of the motor. That was 210,000 miles ago. My symtomes were it would over heat and then go away. I just have to add more coolant. It only happened when it was under a heavy load. Coolant was leaking into the cylinders. If it were me I would replace the headgaskets. Only thing that sucks about subaru is the warranty on head gaskets was 12 months 12,000 miles. Toyota was 36 months 36,000 miles.

The coolant was a little low (nothing major) when I got it checked out earlier this week, but the mechanic and I decided to put off flushing it until the 20th when I'm getting more work done since there are not any symptoms at all. The coolant seems to be staying at the same level from what I can tell.

The coolant was a little low (nothing major) when I got it checked out earlier this week, but the mechanic and I decided to put off flushing it until the 20th when I'm getting more work done since there are not any symptoms at all. The coolant seems to be staying at the same level from what I can tell.

 

Well?

 

I know it was 6 years ago, but how did this turn out?

Since the OP has not signed in since 2016...the world may never know.