Heater Crossover Tube / ECT Coolant Leak

AeroCoupe

lube between the nut and the face
Founding Member
Oct 28, 2001
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Claremore, OK
Anyone ever have a coolant leak at the ECT sensor threads in the heater crossover tube? The ECT is a Motorcraft DY-1145 which I had in the car on the old tube and although it didn’t thread in very far it didn’t leak. I got a new set of tubes and had my buddy cut and tig weld the EGR spacer coolant nipple shut. Installed the new tubes when I replaced the rockers and it leaks at the sensor threads going into the bung on the tube.

I ran a die on the sensor threads and they were not great but they cleaned up. Ran a tap into the bung and they cleaned up pretty quick. Teflon tape on the sensor and it leaked again just like before.

I ordered another sensor but my gut it telling me it’s an issue with the bung on the tube. Anyone else have leak issues in this area?
 
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I would try some pipe thread sealant instead of the teflon tape.... Some of the sealants want you to let them dry for 24-48 hours before using...
I have some ARP thread sealant that seems to work fairly well...
 
I had some pipe sealant I purchased years ago from Home depot... It was called " Gas & Oil" sealant.... I had a much heavier base to it and was good stuff.. I used it when I plumbed my gas piping in my 2nd home...
Not sure if they still have it.... MIght be worth a shot...... Read the instructions, If I can " recall" ( good luck with that LOL ) there was a curing time involved... I used it on everything until it went bad..........
 
It leaked with the Loctite the first time. Second time was teflon tape and some PTFE that I have for head bolts and that leaked. I am begining to think the bung is cracked. Going to get the digital camera out later today and see if I can see it in some high res pics.
 
Was going to say if its leaking with loctite somethings fubar.... Not sure who's still making those for ford but I'm sure quality is just as lacking as it is in the rest of the industry, not the first one I've heard issues about but rest where the swivel fitting leaking. If you where local I give ya a coouple spares, only time I've had them leak is when the o-ring rots out and its pretty easy to replace... Vinegar or Klean strip metal soak will clean up even the crusty ones, then a good trim or vht chassis paint has them looking new... You sure its the sensor and not the joint under the bung? Might try sweating it.
 
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I can relate!
I just bought a Ford made coolant crossover tube from LMR along with a new sensor for my 5.0 Mustang. I noticed neither the new or old sensor would thread very far into the new crossover tube. I cranked on it pretty good before installing it in the car, but was afraid I would twist the bung right off.
I called LMR and they immediately sent new parts. I haven’t tried them yet, but suspect the same results.
The sensor really should be threaded in more than halfway in order to work properly.
I think the bung threads on the new Ford crossover tube are out of spec!
 
Found the problem. Evidently the bung is braze welded into the tube and the weld is no bueno. Its leaking were the red arrow is pointing in this picture:

Fox_Mustang_Heater_Tubes.jpg


Went to OReilly's and got the loaner tool to pressurize the cooling system and it only took one pump on the air pump for this to leak so it has to be a seriously bad weld.

I am taking the old tube and this new one to my buddy Tuesday night and he is going to tig weld the bung to the tube on the new leaking one and remove the EGR nipple and weld the bung to the tube on the old one. He literally just welded up the EGR nipple on the new one which is why I swapped them out. Very sad quality control from whomever made this piece for Ford.

Anyhow, another week down the tubes on driving the car but at least I know it will be fixed right.
 
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That sucks... But brazing ain't hard.... Looks like DCM is repoping the 93 cobra rail, someone used to make a repo of that in black and chrome but it disappeared for years, guess with all the crazy prices there brining stuff back..... Only places I've seen it so far is BOI. Looks like they raised prices on ton of stuff recently though. https://blueovalindustries.com/prod...r-tube-assembly-without-egr-coolant-connector

On the ford ones. Do they have a QR codes or anything on the packaging?. I'm wondering if there selling ford licensed parts as ford now? since dcm has repos of the oem one, and almost everything I've got recently made by them seems to be ford licensed now, guessing holley/drake gave up a lot them.


Edit. Check the review from 2016... https://www.cjponyparts.com/coolant-crossover-tubes-5-0-liter-1986-1993/p/CT2/#reviews. Ford part or repo sold as ford part who knows these days, I'll just buy some o rings and paint my old ones..
 
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