EATC o-ring repair - How to... with pics.

gatlandc said:
This is an excellent repair blog, well done. I followed the instructions and now have cold air blowing on my face again.

One question I haven't seen asked or answered is do you think this o-ring problem could lead to a lean running condition. I also have diagnostic code 171 and 174 up!
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Good question! But the answer is simple....

For some time, the engineers have designed vacuum take-offs such that, in case of a leak, it won't seriously affect engine performance. It's not impossible to happen, of course, but normally doesn't.
 
gatlandc said:
One question I haven't seen asked or answered is do you think this o-ring problem could lead to a lean running condition. I also have diagnostic code 171 and 174 up!
Click to expand...

No, there is such a small loss of vacuum that it doesn't affect the engine. There is also a vacuum reservoir, the flat square box on the left inner fender.
 
So if my max a.c. only blows out of the defrost but on regular a.c it does come out of the vents then the o-rings would be my problem also?
 
i just did this repair, after sitting on the o-rings for about 2 years LOL :) I had the typical 'air out of defrost/feet only' problem.

Worked GREAT! thank you so much for the pics. The first 3 I pulled, the rings looked fine, and felt fine, so I was kind of worried, but the last one I pulled the ring looked ok but was brittle. Replaced all 4, and I have a fully working EATC now for about a $5 and 45min investment. Thank you very much for this detailed and awesome post!

EDIT: if anyone needs O-rings, especially local to new england, I have a bag of them, just PM me and I can probably hook you up.
 
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I know that dielectric grease was used on your repairs.
Has anyone used SILICONE OIL ??
It is very light and you only probably need a drop
on each o-ring after installation.
 
I would assume silicone grease, like plumbers grease would work better by staying in place and not running off the rings. Silicone grease can be bought at home depot or lowes, in the plumbing section.
 
Mine just went bad again. Replaced the o rings but did not work this time. Worked on the last one I did. I think I used ones that are too big or something else went wrong.

Does anyone have 4 of the synthetic ones they could spare?
 
Anyone know of a supplier for the Vacuum Valve Body ?

I followed your suggestions and repaired my own EATC.
I did not see anything wrong with the o-rings but I replaced them anyway
and coated them all with dielectric grease.
Now it blows out of all the vents where it is supposed to.

I DID see some hairline cracks in the valve body so I put a coat of Dielectric grease
on the valve body to try and seal the cracks if they were leaking at all.

:2thumbs:
 
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MENINBLK said:
Anyone know of a supplier for the Vacuum Valve Body ?

I followed your suggestions and repaired my own EATC.
I did not see anything wrong with the o-rings but I replaced them anyway
and coated them all with dielectric grease.
Now it blows out of all the vents where it is supposed to.

I DID see some hairline cracks in the valve body so I put a coat of Dielectric grease
on the valve body to try and seal the cracks if they were leaking at all.

:2thumbs:
Click to expand...

If you take a close look at the o-rings you will see that they are square not round as they should be.

Use silicone dielectric grease. Silicone oil will not work.

Since the air is coming out where it needs to the valve body is not cracked. You probably saw the cast marks.

I highly doubt you'll find a valve body anywhere.

To fix a leaking valve body:

  1. Remove the solenoids and wiring from the valve body.
  2. Since you put the silicone grease on it, clean it really really good to get rid of all the silicone grease.
  3. Get some 5 minute epoxy
  4. Mix the epoxy
  5. Fill the void in the top and bottom of the valve body with the epoxy (obviously you need to do one side at a time)
  6. Don't get any epoxy inside the valve body.
  7. Reassemble the solenoids after the epoxy is dry
 
MENINBLK said:
Can you just use clear nail polish to do the same thing ?
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As Jim as noted above - not a likely solution. You have to remember that the type of plastic used in this valve system is designed to be used "bare." That is, the O-rings used inside the valve make (an otherwise) good seal using the natural surface of the plastics. It is also rigid for support purposes (of the solenoid valves). That rigidity also contributes to its one flaw - that it can hide hair-line fractures during the manufacturing process, which, upon hot and cold cycles, become exposed.

Those same hot/cold cycles also play havoc with the o-ring seals as well.

From all I have seen over the last several years of this problem, here, on this forum, the vast majority of the problem are indeed the O-rings. The rest seem to fall into the cracked valve body problem.

I have examined about 10 of these valve bodies so far, locally, for friends with "the problem." Seven needed o-ring replacement, the rest were valve body cracks. What started this "quest" for me was finding that the O-rings did nothing, and I drove Jim nuts trying to help me. I guess the engineer got the better of me after a while, and it took a bit of doing to hook up vacuum pumps and other accessories to ferret out the cracked valve body.
Worse yet, I found that the valve body could not be repaired using conventional means of gluing, due to the type of plastic used. Double-worse yet, some of the cracks I found in the other valve bodies were not external, but rather internal, meaning no amount of adhesive would matter.

Bottom line - if you have a cracked valve body, your choice is replacement. Ipso facto! :bigcry:
 
Good news is these units are relative easy to find in the junk yard. We took apart one last week and the o rings were hard as rock. They literally broke off when we pried at them.
 
Anybody in here got some spare silicone O-rings in the 007 size needed for the repair that they could send my way? I've got the typical problem: air out of defrost vents only.
 
Guys, if you sent me your mailing address for o-rings, I can't find them!! :(

Somewhere in this house is a package with about 70 o-rings. I must have put them away somewhere they'd be safe. It's driving me nuts! Don't know where else to look and my OCD won't let me quit looking!!

Sorry for the delay.
 
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