Hello, Allpar Forums member or visitor! If you were a member, you would not see this ad!

Register or log in at the top right of the page...

  1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

Head gasket? - Subaru

Discussion in 'Non-Mopar Tech Support' started by neoncrazy101, Jul 12, 2015.

  1. neoncrazy101

    neoncrazy101 Member

    Joined:
    Mar 17, 2014
    Messages:
    51
    Likes:
    4
    Hey guys, so I bought a 04' Subaru Outback w/ the 2.5L (92k on her) for my wife last week. Had paper work showing that timing belt, water pump, head gaskets (plus all related items), thermostat and radiator cap were placed within the last few months. I test drove it and it ran like a charm, no overheating or anything. I drive it home an hour, no overheating or anything. It sat for a few days till I could get new tags on it and the first time out, it overheated after merging onto a freeway, few min. passed by and she cooled down (when I say a few min., I mean a few min.) thought that was odd but what the hey. So I started her back up and went to merge back over and she overheated again. Pulled over and same thing, except the radiator cap and upper portion of the radiator were cool to the touch. Oh and there was no "hot" engine smell.

    I get to my destination and drove it back home and didn't overheat at all. I burped the system that night thinking it was an air pocket from when they did the work, lots of air came out. Next day, I drove it to work and I merged onto the highway and same thing. Except this time the reservoir overfilled and blew the cap off so I lost a ton of coolant. After work I drove her home without any overheating issue at all. I then proceeded to look around the heads and saw nothing, no weeping or anything, I did a block test and it came back negative (I did it three times to make sure), there's no smoke or residue in the exhaust, no coolant in the oil and vise versa.

    Yesterday I changed out the thermostat and the cap to a Subaru OEM thermostat and cap (there was an actual difference between the parts installed and the parts from Subaru), drove her and merged onto the highway and she did not overheat. BUT she almost overflowed the reservoir and by this morning, she did not return any of the coolant to the radiator. So I figured, everything else has been changed why not change the radiator and coolant hoses. So I did that and took her for a drive and no overheating, she did go past the full mark on the reservoir but I don't know if she's pulled any in yet (only been 20 or so min). But I smelled the reservoir and it had a slight fuel smell to it.

    SO recap.

    No white smoke
    No coolant residue in exhaust
    No visible sign of head gasket weeping/leaking
    No oil in coolant and vise versa
    No exhaust gases in coolant
    Fuel smell in reservoir
    All new cooling system.

    Everyone on the Subaru sites are saying headgasket, but it seems like with every overheating issue they say "Headgasket!" so idk. Any ideas guys/gals?
     
  2. dana44

    Ad-Free Member

    Joined:
    Jun 17, 2002
    Messages:
    19,326
    Likes:
    1,238
    Not too familiar with the Subaru itself, but purging can be fun at times, and from there, holding the pressure, as in radiator cap itself. It's always best, since everything is new, get the front of the radiator up high enough when purging the system, rev several times to make sure the flow is moving and fluid is pushing the air out of the engine. Also, the radiator cap itself may be a problem, not the first time one doesn't hold pressure so any heat will push fluid out easier than it is supposed to.
    Now, on the repair work, were the injectors checked? If not, full throttle merge, a ton of heat is being made in the cylinders, and if the injectors are running lean, that heat and temp goes way up, which is a head gasket blower and valve burner. If they weren't checked, burned valves and head gaskets can quite often be directed to bad injectors, and the thing is, unless you are burning oil, plugs usually run so clean these days you can't tell with the tips of the spark plugs like the old days.
     
  3. neoncrazy101

    neoncrazy101 Member

    Joined:
    Mar 17, 2014
    Messages:
    51
    Likes:
    4
    With regards to the radiator cap, this is the third time its been changed out within 2k according to the paper work. The place though didn't put in an OEM cap and there were rather visual differences between the Subaru part and whatever they put in.

    Injectors were not checked. I never even thought about the injectors. How can you check to see if the injectors are running lean or not? Or is that a shop test?
     
  4. dana44

    Ad-Free Member

    Joined:
    Jun 17, 2002
    Messages:
    19,326
    Likes:
    1,238
    You can search around for a shop that will have the ability to test them. The thing with injectors is, if one runs lean, the others will enrich to make what is coming out the tailpipe look good according to the O2 sensor, so they have to be flow checked to endure they squirt equally, that's the key. I just recently had a V8 engine that was running with three good injectors and if it wasn't for a IR temp gun, wouldn't have really known it was doing this, five cylinders were cold. I was lucky, we were able to take compressed air and get them to start flowing, the engine had been sitting for about five years so they were gummed up, not plugged up. Once they were unstuck, so to speak, they were fine. I look to the injectors based on the fact it was the on-ramp that would increase engine temp with near or full throttle and overheat, given blown head gasket tests have been done.
     
  5. neoncrazy101

    neoncrazy101 Member

    Joined:
    Mar 17, 2014
    Messages:
    51
    Likes:
    4
    Welp, it was a headgasket. Injectors are good though I believe. I took my IR gun and all the cylinder area's were pretty close to eachother in temp.
     
  6. dana44

    Ad-Free Member

    Joined:
    Jun 17, 2002
    Messages:
    19,326
    Likes:
    1,238
    Well that kind of sucks, given they were just recently changed. Make sure both the block and heads are checked that they are flat, head bolt holes are clean so the head bolts tighten completely, been more than once that a simple bolt hole was dirty and allowed a head bolt didn't clamp properly (see Neon head gasket problems, one bolt hole was something like .010 inch too shallow and was a problem, gave Neons a bad rap because of it).
     

Share This Page

Loading...