By-pass pipe O-rings and other leaky stuff

[JB83]

I'm getting ready to button up the install of a replacement '85 engine in my '83 SR5. I filled the cooling system with water to check for leaks. Two leaks, two questions for you guys:

1. The lower end of the by-pass pipe. New O-rings, right? The guy at Napa said he's got no way to look that part up. Couldn't find a part # in my ('87) FSM. Is it a dealer-only part, and if not, does anybody know where I can get the O-ring set and what the part number is?

2. Where the heater inlet/outlet comes into the rear of the engine--two bolts, one was loose so I tightened them both--seems to have fixed it for now, but I'm not happy with it. Is there a gasket under that thing? If so can I get it separately? What do I ask for?

[takza]

I did a writeup on the o-rings and bypass tube...mine's been hanging together ever since I redid it. I just used nitrile rings and sized them by sight. And lots of cleaning and gasket goop.

.......the other thing I don't know about. For something like that...you might buy the rubberized gasket material in a roll and make one yourself.

[simon84]

I've had good luck with some silicone sealant on the bypass pipe.
Not sure about the heater hose gasket. If tightening it worked then I say go with it.
If it ain't broke, don't fix it!

[Highlander]

There's no oring or anything on the rear head bolt- I forgot to tighten that one when I put the base engine in Yo deux, I simply tightened the bolt and it stopped pouring out- no problems since with leakage. I bought s pair of the o-rings for the bypass tube about 4 years ago, still have them sitting around (somewhere).

[JB83]

Well, after reading your replies I called the local dealer and he's got one set in stock.
** $3.66 per O-ring! ** Damn, food's not the only thing going up and up.
But at least no guess work, so I'll bite the bullet and get them, and keep a close eye on that rear heater pipe flange issue. Thanks guys.

[sdoan]

Well, after reading your replies I called the local dealer and he's got one set in stock.
** $3.66 per O-ring! **

If you haven't spent the money yet you can take the old ones and the pipe to Lowes and size them by sight. I ended up buying 2 different sizes just to be sure and they're still working 2-3 years later. Think it cost be $2 for 4 o-rings. A good autoparts store should have an o-ring assortment you can select from too.

It is so hard to get to that water inlet on the back of the head that it is probably worth just tightening the bolts and see if that stops the leak. If it doesn't stop it, remove it and spend a lot of time making sure it is really clean and smooth or it won't seal. I used paper gasket material and a thin film of silicone gasket sealer - but the engine was out of the car at the time. The Gasket material is available in different thicknesses at auto parts stores and good hardware stores.

Good luck

[JB83]

That's good to know, I might do the Lowe's or Napa thing. The irritating thing about that heater inlet leak is that I had the engine out and neglected to tighten those up before installing it. And now they're a beast to get at unless your hands are the size of a toddler's. Oh well, live and learn...

[takza]

After going to NAPA and buying a couple o-rings for over $.50 each to do mine...I later bought this:

http://www.harborfreight.com/cpi/ctaf/d ... mber=93143

...though the one I bought looked exactly like the assortment I bought them from....their cost...less than $.03.

I'm tending to buy a lot of these assortments....because whenever you get into a job and don't have a part it is a PITA and now an extra expense with high gas prices to go chase after something.

[JB83]

Well, so far so good, with the Napa O-rings and the torqued-down rear heater bolts she seems to be holding water. A few more things to button up. Like I was doing a visual scan of the replacement motor and saw that two of the carburetor hold-down nuts were missing! The other two were loose. Luckily I still have the old motor to pirate stuff off of. I bought the engine from a private party off Craigslist, so am hoping for the best. Fun project so far, not so fun if it turns out the motor's got problems, but I'll know soon. Thanks again for the help you guys.

[swifty]

bought 88 4wd new and bypass pipe (aprox 2 inch metal pipe near thermostat) started leaking at 80K.. Lost coolant slowly and was tuff to figure out from where. Leaks a bit then dries from engine heat. I think all the original ones leak, just tuff to spot.

Went to dealer to get new orings and was told there was an UPGRADE TO THAT PART. So i bought it...was bit heavier construction and apparently slightly larger diameter. Put it in and no leaks for another 260K hehe..

Did rad and waterpump at 340K and... bypass hose was leaking too. Since I had upgraded pipe...went seaching for o rings.. was tuff but u can find them if u have hardware or parts store with a tray of warious sizes to size it out.. You have to pick ones that just clear the o ring groove... has to just clear or u won't be able to slip it in..

hope this helps.. Old girl just turned 352K and is getting a little tired but runs and drives exactly same as new.. Hardly fixed a thing on this car and when u do it is so easy to fix.. I love my wagon because every other car i drive i do not like it as much.

[Petros]

Wow, and upgrade to the by pass tube. I have owned three T4wd, and only once did this o-ring give me trouble. That was because I was careless when install the head and I damaged the o-ring. I found that the standard tube with a new o-ring and a light coat of RTV works fine, I have even re-used the old o-ring if it looked okay with good results.

Of course I have found these tubes all rusted and pitted out sometimes, if I did not have a replacement I would use lots more sealant on it.

[4wdEconoBox]

Sorry to bump an old thread, but does anyone remember the size O ring they went with for the bypass tube?

[rocketscience]

Yeah they're size #112.

[4wdEconoBox]

Alright, thank you!!