Heater tubes were leaking, now fixed.

Discussion in '1994 - 1995 Specific Tech' started by ratio411, Jan 5, 2013.

  1. I had SN95 heater tubes leaking right at the 2 piece joint that screws into the intake manifold.
    Leaking like a water hose with a thumb over it!

    I was asking around, trying to find a new set of tubes, or find out if these could be fixed...
    I couldn't find any replacement tubes for an SN95, and everyone told me they were not serviceable.

    Since the set I had was leaking, and I figured I couldn't make it worse, I decided to take them apart and see if I could repair them.

    I took off the lower threaded portion of the joint, and found 2 grooves on the inner portion that appear to have had o-rings in them. So I cleaned them up, installed some o-rings, lubed it up, put the lower portion back on, and used a punch with increasing diameter to expand the bottom swedge back into place.

    I put 17# on the system, and it held fine. Then I drove it today with the 13# cap, and it didn't leak a drop.

    So if you were wondering, the heater tubes are serviceable at the spinning joint.
  2. Thanks for the info.
    I'll probably do the same to a spare hardline I have here.
    My original has some slight seepage after the gt40 swap I did last week.
  3. I knew how rare these were and no replacements are made for our cars.

    I spotted one on ebay and purchased it right away. Glad you were able to repair yours.
  4. I guess I never thought about it before, but is the heater tube for 94/95 THAT much different than the one for 86-93?
  5. I think the configuration at the rear of the engine where the core hoses attach is different. The fox tubes also have the provisions to cool the EGR plate.
  6. I had some Fox tubes I could have installed, but it wouldn't have been right.

    The differences I saw:
    The Fox tubes are smaller diameter on both tubes, and one tube is smaller than the other.
    The SN tubes are the same diameter for both tubes, and they are bigger than the big one on the Fox.
    The SN tubes are lower profile. The Fox tubes sit up higher in the area between the valve covers and injectors.
    The Fox tubes place the coolant sensor vertically between injectors 1 and 2, while the SN places the sensor horizontally above the thermostat housing. If Fox tubes were on an SN engine, the sensor will stick up right where the SN fuel hoses snap into the fuel rail.
    I believe it would fit there, but that spot would become very crowded. You would also have to modify the harness a bit to move the sensor connector to the Fox location. No big deal, but not an attractive option.
    The heater supply hose from the water pump to the tubes would have to be longer. The SN tubes go straight and low to their connection point, while the Fox tube sweeps upward for whatever reason.
    Where the heater hoses connect to the tubes is the only spot where the units are identical, and that was the spot I thought would be the biggest difference. Other than the tube sizes, they are identical in the rear. You could use the smaller tubes, but you would have to use a worm gear clamp and tighten the pizz out of them to get the big hoses sealed on the smaller tubes.
    Then lastly, there is a 5/16" hose nipple on the side of one of the Fox tubes to feed the EGR block. This would have to be plugged to use on an SN, and to me it is just one more place to leak.

    I am going to get another SN set of tubes to put on my 87.
    I intend to delete the EGR, and the lower profile tubes seem to be a cleaner install IMO.
    I'll just have to adjust heater hose size accordingly.
  7. Grab these up and conserve them my friends.
    They don't make them anymore, anywhere...
    The Fox tubes are still made and available new.
    I don't know if those are repops, or new 0ld stock, but the Fox tubes don't seem to be getting rare, while the SN tubes are going to get hard to find.
  8. I always wonder why Ford put so many subtle differences into the '94-'95 cars versus their fox counterparts. All the fox componentry seems to fit on an SN95; kind of makes you wonder what the point was.
    ratio411 likes this.
  9. Some pictures for you guys.
    I tapped the flare of the tube down some with a punch and hammer, and the threaded fitting slid right off.
    The lower o ring came out as dust with the fitting.
    The upper o ring is a little chewed up with some flat spots.

    Also, I believe the 91-93 5.0 t bird/cougars use the same coolant hardline.

    Attached Files:

    ratio411 likes this.
  10. Great thread guys. :nice:

    Davis, I can't see your pics. :(
  11. A bit O/T, but I have an electrical fan issue that has me befuddled and will post a new thread on it here in a minute...
    Could you have a look at my problem and maybe give me a thought?
    I went over your tech info online and it has helped, but I have hit a dead end.
    Once I have to start navigating schematics, I get completely confused.
    I am handy with a test light, but that's about it.
  12. Thanks for adding the pics!

    You have confirmed my belief that there are o-rings in these from the factory.
    My o-rings must have been dust!
    I had every sign that these had o-rings, but no proof.

    Your second pic showing the inside of the lower fitting:
    I didn't mention, I cleaned the heck out of mine, trying to make it as smooth inside for the new o-rings, including lubrication just before reattaching it to the upper portion.
    Mine did not have rust, but rather dry crust (probably o-ring dust!), if mine had rust like yours, I would lightly sand it out of there. Just a thought.

    Thanks again for the help!
    The thread needed it!

    Attached Files:

  13. No problem.
    I did lightly sand the threaded portion before putting it back together.
    It came off very easily and I lubed the o rings before putting it back together.
    I used a tapered spindle I had laying around here to flare it out.

    I'll post up a comparison later between the explorer/94-95 mustang 5.0/fox 5.0/tbird-cougar 5.0 once a 1/2 off day at the wrecking yard rolls around.
  14. I looked under the hood of a T-bird/Cougar 5.0 today, think it was a 91.... ???
    The tubes are different
    So don't worry about those.

    The back, at the firewall bends and swoops upwards, the heater core tubes at the firewall are located substantially different than a Stang.
    At the front, the ECT is in the same location, but the temp sender for the gauge, that is in the driver's side manifold on Stangs, is located on the top of the rail.

    I wouldn't bother with these myself.
    The driver's side boss that has the gauge sender in our cars has some sort of sender, and it is large... bigger than the ECT.
  15. Not a problem.
    I wasn't much help but I tried Dave.

    Harvey, it was obviously an issue on my end - I can see the pics today. :nice:
  16. Ah, cool Hissin.

    Ratio, I'll probably still do the comparison later.
    It'll give me something to do when I'm bored
  17. Any idea what size the o rings you used were ? mine is leaking and I'd rather fix mine than roll the dice on a used one that may have the same problem.
  18. perfect... now here's hoping to not crack the line in the vice !
  19. All the way around.
    I'll clear that up in the "How to" thread.
    I was in a rush to get to work when I wrote it, haha.