Could it be anything other than impending head gasket doom?

I have a 1998 Subaru wagon that had to have a new headgasket right after we got it used. The dealer replaced it free and we thought we were in the clear for a good long time. Unfortunately, we just took it in for a starter problem and were told that the head gasket will very likely go out in the next couple of months. The reason for this conclusion is that they found bubbles in the cooling system and a hydrocarbon level of 870ppm in the coolant. The car is not overheating at all and I just added coolant (probably too much) into the plastic reservoir a few days ago. My questions are: Can the symptoms they observed be caused by anything else? Could my adding of coolant be skewing the data? Since it is a $3500 repair on a car only worth $7000, I want to be sure it’s worth it! Thanks!

$3500 for both head gaskets or does that include starter work? Even so, the price sounds much too high. Ethylene glycol (antifreeze) is loaded with hydrocarbons. I expect that they would find a lot more than 870 PPM in antifreeze. I would want to know what kind of instrument they used to measure hydrocarbons in coolant. You need to shop around for another quote. I smell scam here.

I would have to agree with “Wha Who”'s comments above. The price sounds way too high, even for a dealer. If the car is no longer under warranty, there is no reason to keep going back to the dealer. Find a reputable Subaru mechanic in your area.

I don’t know what the concentration of HC’s (hydrocarbons) is in typical antifreeze, but I would highly doubt any analysis of that type done by a garage. They probably used some sort of photo-ionization detector to “sniff out” the HC’s in the antifreeze. Those machines are not that accurate and a lot of people who use them don’t know what they’re doing. If they told you that the level is exactly 870ppm, I wouldn’t believe it… its likely just a guess.

Sounds fishy to me. Take it to a good private shop for a second opinion. I’m sure I could find hydrocarbons in the coolants of a brand new car, since antifreeze is a hydrocarbon. The bubbles are something to investigate, however. The r3pair cost sounds definitely excessive.

First off, you have a plural involved. Subaru has head gasket(s); two of them. Hopefully they replaced both at the same time.
It’s unknown to any of us as to whether both were replaced, were the head(s) resurfaced as needed, or were both head gaskets even replaced.

A head gasket diagnosis should be a combination of tests; hydrocarbon test, vacuum gauge, compression test, cooling system pressure test, etc.

Considering the bubbles and hydrocarbon level it could be a failing head gasket. It is also quite possible for a car to have a failing head gasket and not overheat.

You might try this. After the car has sat all night and is cold, loosen the radiator cap to relieve any pressure.
Retighten it and start the engine.
Allow it to idle for about 30-45 seconds or so. Shut it off and quickly loosen the radiator cap.
If you hear a slight hiss then a head gasket(s) might be failing.

(Also, that 3500 sounds way too high on head gasket(s) and starter combined; and since the starter may be a problem exactly what are the symptoms. Subaru starters seldom ever fail.)