coolant leak between thermostat housing and housing connector (2005 V8)

Lincoln LS

  1. XR$Ti

    XR$Ti LVC Member

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    Lots of great threads here on coolant part replacement, but here's my problem.

    I replaced all the plastic pieces and gaskets in 2016, 20k kms (12k mi) ago, 2005 V8. I have a leak at the joint between the thermostat housing connector (the angled tube that goes to the block), p/n 2W9Z-9N499-A, and the thermostat housing, p/n 3W4Z-8548-AD. These are the Tasca item names. These are the two parts that just press together and rely on a wide gasket, and the fact each is individually bolted to the block, to keep them sealed. Is there any way to keep this joint sealed (yes, I lubricated the gasket seal with coolant when assembling). Can it be sealed better? What about disassembling and using a sealant of some sort? Just seems like this joint can't take the pressure. I noticed there's what looks like provisions for a spring-loaded wire clamp or something formed into both pieces.

    I'm just miffed at having to buy plastic parts and seals again after such low usage and it seems like such a weak spot.

    Any advice/suggestions?

    Links to the pieces I'm talking about:
    OEM Ford Radiator-Thermostat Housing Connector 2W9Z9N499AC | TascaParts.com
    Thermostat Housing - Ford (3W4Z-8548-AD) | Tasca Auto Parts

    Thanks.

    EDIT: Just to be clear, all parts were OEM.
     
    Last edited: Oct 16, 2018
  2. joegr

    joegr Dedicated LVC Member

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    Really, it's a big o-ring and not a gasket. I had a lot of trouble when they were sending a slightly wrong size for a while, but they later sent the right one (all were the same part number). Anyway, that's probably not it if it worked for over a year.

    That provision is for a plastic clip that Jaguar uses.
    aj89485.jpg
    I think that it is really just a shipping thing. I can't see it making any difference with it installed.

    That o-ring is easy to roll and twist as you are putting the parts together. If it twists, it will leak.
    This stuff is good to put of rubber seals and o-rings: www.amazon.com/gp/product/B000HBNT14/ref=oh_aui_search_detailpage?ie=UTF8&psc=1

    All this said, are you really sure that the leak is coming from there. I had a leak on my 04 after replacing all the parts. It sure looked like it was coming from there. I redid it a few times and had the same leak. It only leaked when the car was being driven. I wrapped clear tape around the connection. The coolant was on the outside of the tape, not the inside. Apparently, the leak was spraying from where the crossover met the cylinder bank on one side. I sanded off some residue from the previous gasket and applied tack & seal, and that resolved it.
     
  3. XR$Ti

    XR$Ti LVC Member

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    Thanks for the info. I yanked it all out last weekend to inspect. The o-ring looked fine, as did the other interfaces. The only place I could track staining back to was that joint. And today I could see a drip forming and running down, so I could be wrong, but I'm pretty sure it's the joint b/w the two. Maybe I'll try some gasket sealant on it (and make sure mating surfaces are clean), thanks.
     
  4. joegr

    joegr Dedicated LVC Member

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    Yes, sounds convincing for where the leak is.
    I don't know if sealant (RTV, I assume) would work very well. It seems like it would break free before too long due to thermal expansion/contraction. Once it does, any on the inside may clog something (thermostat, DCCV, heater core, ...).
     
  5. XR$Ti

    XR$Ti LVC Member

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    Yeah, I've got a cart filled at Tasca with new parts and gaskets/o-rings, just in case. Just waiting on whether i should pull the trigger...
     
  6. White LS

    White LS LVC Member

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  7. White LS

    White LS LVC Member

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    What is the part # for the o-ring?
     
  8. joegr

    joegr Dedicated LVC Member

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    -W707299-S300
     
  9. White LS

    White LS LVC Member

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    Thanks for the info.
     
  10. nghtshd88

    nghtshd88 Well-Known LVC Member

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    Ironically I unfortunately had the same exact leak on my 05 about 2 months after install. All OEM from tasca.. those two pieces were hard to push together and I had a feeling they'd leak.. I refuse to remove the upper intake again as that was a major PITA. Now Im losing an inch of coolant every 100 miles. Got a new O-ring and some sealant. Hoping to get it on without removing the upper..
     
  11. White LS

    White LS LVC Member

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    Picked up another o-ring and some new sealer. Started with a slight leak that has been leaking more lately. Have replaced all rubber hoses and plastic cooling components.
     
  12. nghtshd88

    nghtshd88 Well-Known LVC Member

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    What sealant are you using? I wish these two pieces bolted together or used a clamp.
     
  13. White LS

    White LS LVC Member

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    JOEGR suggested using Permatex 80938 but I couldn't find it local so I am going to try Permatex 85420, has a lot of the same properties as 80938
     
  14. XR$Ti

    XR$Ti LVC Member

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    Not necessary to remove the upper intake. I've pulled these parts off twice now (the original, then my replacement) without problem and will do a 3rd time now that I just got my new parts. I do have to remove the TB and housing that runs to the intake. Last time I removed the EGR, but I don't that needs to be done either (just disconnect it).
     
  15. nghtshd88

    nghtshd88 Well-Known LVC Member

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    I was going to do that also but if I recall you have to cut the bolts on the elbow thats bolted on to remove it without taking the intake off. Am I wrong? Or youre simply pushing it on to that piece while still bolted?
     
  16. XR$Ti

    XR$Ti LVC Member

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    Hmmm... good question. I forget what I did originally now. Maybe cut them to get them out and then put in shorter ones when I assembled. They are shorter than the others. Assuming I did that, it was way easier than pulling the intake.

    I am replacing both pieces as I don't know which one is at fault and would rather not take it apart again.
     
  17. nghtshd88

    nghtshd88 Well-Known LVC Member

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    Took mine apart today and think this is another design flaw on the LS (no yellow clip).

    The coolant was for sure coming out the O-ring between those to pieces. I traced it to the top of the two and realized the top doesnt fully seat like the bottom does. You can see how the top is almost flush with eachother while the bottom is pushed in.

    Thinking this was my fault on install I took pliers and pressed them together and coolant gushed out while the two moved good amount just resting back the way they were incorrectly..

    That plastic clip would correct this issue as nothing holds them place on top.. Is there a part number on jaguar for it? Probably a good idea to just order from them going forward if so. I dont want to risk putting another o-ring in for no reason when its just going to force itself apart under pressure.. again....

    20181024_153655.jpg

    20181024_153754.jpg

    20181024_153709.jpg
     
  18. joegr

    joegr Dedicated LVC Member

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    I don't know. I feel like the design is good, because it is working just fine for most of us. Maybe they changed o-ring suppliers again, and the o-rings are not quite right? Or, maybe they aren't molding the new elbow or the outlet pipes to the exactly right dimensions?

    Here's a pretty good Jaguar parts breakout, but it doesn't show the clip.
    https://www.google.com/url?sa=t&rct...cat_s_en.pdf&usg=AOvVaw0e9nPyPEMbuf87RHaBwJcT
     
    Last edited: Oct 25, 2018
  19. XR$Ti

    XR$Ti LVC Member

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    Miine appeared to be leaking from the bottom (unless it dribbled down from the top, but I don't think so). But in looking at your pic, yeah it's obvious how it's not inserted as much at the top. It would sure be nice to remove that joint in favour of some clamps and a hose.
     

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