Coolant Leak at Heater Hard Line Bracket under Exhaust Manifold

[suprabee]

I’ve been working to replace the exhaust manifold gasket, and while removing the turbo notice coolant dripping from the hard pipe just near the 90 degree hose. No big deal I thought, as I expected it to be the hose. It was not. I have a leaking spot weld at the rear most mounting tab just before the line bends around behind the engine. You can see where the weld is leaking by the copper color right underneath the line. I’ve made sure that it is not leaking from the union bolt on top of the head and dripping/running down by wiping everything clean/dry and let sit for a while, and the rubber hoses are also not leaking. Eventually FRESH clean coolant appears right at the weld on the mounting tab.

….DAMIT! #$^@&*% !!!!

My first thought was….ok just replace the entire hard line, but WTF am I going to have to remove the intake plenum and runners as well to pull the line up between the head and firewall? It won’t just pull out from the exhaust side due to the 90 degree angled small pipe that bends around the corner of the head and runs coolant to the throttle body.

SO, How do I tackle this?

I see 4 options:

1. remove intake stuff, which I really really don’t want to do. Just had the intake removed back in Sept. for cleaning while replacing valve stem seals.

2.pull motor…really, really…. really don’t want to do that, In fact, I don’t have the means to do that kind of work.

3. somehow get in there with a hack saw blade and cut that small angle line off the main pipe so I can pull the pipe out from the exhaust side. But then I have the issue of installing the new pipe and how to get it in place….

4. OR…could the spot weld be re-welded? I have no welding knowledge, so advice if this is possible would be great. I am thinking it should be a possibility and in the end probably be less time involved as long as the new weld holds.


I’m going to have to find someone who can come to my house and try to weld this I guess. I really want to try option #4

ALSO, after much searching I found many people with a “mystery coolant leak” in the same area. Most threads never came to a resolution. I bet that many of these leaks are just like mine. I only found one post that mentioned the same spot weld leak back in 06 by Supra here, post #15

http://www.supramania.com/forums/showthread.php?t=26996&highlight=coolant+line&page=2

or to quote Supra… “Last - I've seen this problem happen when I used a bad hard line once. The two mounting tabs are spot welded and corrosion happens at these points..”


Any other ideas? options?
Rick

 

[IwantMKIII]

My bet would be on the fact you could drop a few more spot welds on it from someone experienced. If not, hoist the engine up some and go from there. You don't need to completely remove it. Its not that difficult. I don't remember what bolts are holding that pipe on but be SURE you can't get to them before doing all this work and replace the pipe.

 

[suprabee]

Ok..thought about it....guess I'll answer my own thread :icon_bigg

I going to clean, prep, and solder the bracket/weld using 50% lead/50%tin solder..maybe 60% tin/40% lead if I can find some. As long as I can get everything clean and prepped well, the solder should set and it should not leak.

Using a dental mirror I was able to see that I'll also have to solder up the side of the bottom pipe along the bracket as well. There is not much room to move around with a torch, so it is going to be tricky.

rick

 

[zdatsupra]

I’ve been working to replace the exhaust manifold gasket, and while removing the turbo notice coolant dripping from the hard pipe just near the 90 degree hose. No big deal I thought, as I expected it to be the hose. It was not. I have a leaking spot weld at the rear most mounting tab just before the line bends around behind the engine. You can see where the weld is leaking by the copper color right underneath the line. I’ve made sure that it is not leaking from the union bolt on top of the head and dripping/running down by wiping everything clean/dry and let sit for a while, and the rubber hoses are also not leaking. Eventually FRESH clean coolant appears right at the weld on the mounting tab.

….DAMIT! #$^@&*% !!!!

My first thought was….ok just replace the entire hard line, but WTF am I going to have to remove the intake plenum and runners as well to pull the line up between the head and firewall? It won’t just pull out from the exhaust side due to the 90 degree angled small pipe that bends around the corner of the head and runs coolant to the throttle body.

SO, How do I tackle this?

I see 4 options:

1. remove intake stuff, which I really really don’t want to do. Just had the intake removed back in Sept. for cleaning while replacing valve stem seals.

2.pull motor…really, really…. really don’t want to do that, In fact, I don’t have the means to do that kind of work.

3. somehow get in there with a hack saw blade and cut that small angle line off the main pipe so I can pull the pipe out from the exhaust side. But then I have the issue of installing the new pipe and how to get it in place….

4. OR…could the spot weld be re-welded? I have no welding knowledge, so advice if this is possible would be great. I am thinking it should be a possibility and in the end probably be less time involved as long as the new weld holds.


I’m going to have to find someone who can come to my house and try to weld this I guess. I really want to try option #4

ALSO, after much searching I found many people with a “mystery coolant leak” in the same area. Most threads never came to a resolution. I bet that many of these leaks are just like mine. I only found one post that mentioned the same spot weld leak back in 06 by Supra here, post #15

http://www.supramania.com/forums/showthread.php?t=26996&highlight=coolant+line&page=2

or to quote Supra… “Last - I've seen this problem happen when I used a bad hard line once. The two mounting tabs are spot welded and corrosion happens at these points..”


Any other ideas? options?
Rick

I recently did number 3. I cut off the small line that feeds the throttle body. This makes installation very easy.
The hose that goes into firewall will still fit on the large pipe.
Im in Fl so i dont need the water going to the TB. The nipple under the manifold that feeds the other side of the tb can be removed and replaced with a plug.
Makes future removal of the hard line a snap.
When mine had a crack in it I cut it off on the exhaust side and removed it in two pieces. I got a hard line that was used and in not so good of shape, so I did not mind experimenting.

 

[Zumtizzle]

It's not welded.

It's braised with solder.

 

[WhtMa71]

^ That's what I was going to say. Re braze it, don't weld. Make sure you put a nice piece of metal between and engine so you don't heat it and to catch any dripping solder.

It might be a pain because when you heat the pipe it will probably melt the solder between the bracket and pipe and drop the bracket off..

 

[suprabee]

^ That's what I was going to say. Re braise it....

It might be a pain because when you heat the pipe it will probably melt the solder between the bracket and pipe and drop the bracket off..

ah a braised junction...I thought that it really didn't look like a weld.

I won't have to heat it up to the temp that a braised joint would let go, only in the 300-400F range to melt the solder. Hopefully, just a quick solder will do the trick.


...another idea I just thought of....If the bracket comes off, then I would be able to separate the two pipes a bit. Put a good helping of ultra gray sealant on the pipe, take 2 inch long piece of hose sliced down one side and fit it over the pipe. Then get a wide hose clamp and tighten it down around the hose/pipe...make a patch basically with the hose, clamp, and ultra gray...that might also do the trick...FYI the leak is not very substantial to begin, so its not like I'd be trying to patch a gusher.
RIck

 

[IJ.]

brazed

 

[the t3d]

i just noticed i have the same problem and it's pissing me off. i have alot of accessories under the hood too. it's fully built with not even 3000 miles on it and i notice this shit. it's my daily and don't really have time to pull the motor out again, so i'm also looking for the easiest way to replace the pipe, not patch. so any update on this would be great!

-t3d

 

[jetjock]

It's braised with solder.

Spelling aside, technically there's no such thing but I'll let it slide

 

[WhtMa71]

Yea, I guess it might not be a good idea to Braise the pipe..

Braising (from the French “braiser”), is a combination cooking method using both moist and dry heat; typically the food is first seared at a high temperature and then finished in a covered pot with a variable amount of liquid, resulting in a particular flavour. Braising of meat is often referred to as pot roasting, though some authors make a distinction between the two methods based on whether or not additional liquid is added.[1][2]

 

[the t3d]

Yea, I guess it might not be a good idea to Braise the pipe..

Braising (from the French “braiser”), is a combination cooking method using both moist and dry heat; typically the food is first seared at a high temperature and then finished in a covered pot with a variable amount of liquid, resulting in a particular flavour. Braising of meat is often referred to as pot roasting, though some authors make a distinction between the two methods based on whether or not additional liquid is added.[1][2]

was the definition and full history of the word really necessary? lol

-t3d

 

[3p141592654]

Getting back to the thread, though, I thought those pipes were stainless?

 

[enawazh]

jbweld

 

[the t3d]

jbweld

i mean is that really a good fix? getting a new pipe from toyota would run me around 160 bucks...ouch!

-t3d

 

[adampecush]

I'm pretty sure that line is aluminum, so if you are going to solder, do so with the appropriate filler and procedure.

(I sandblasted the line before re-installing and I did not paint it....I assumed the line was Al based on the fact that it did not rust, and the use of SS would have not been cost effective from a manufacturing standpoint therefore unlikely)

 

[IJ.]

They're steel Adam

 

[3p141592654]

Perhaps the 86-88 were steel, I've never touched one. The 89+ do not look like steel to me. There is a part number change from 88- to 89+. A magnet test is in order...

 

[hvyman]

i just removed one from a newer block and it does not seem to be AL.

 

[IJ.]

Perhaps the 86-88 were steel, I've never touched one. The 89+ do not look like steel to me. There is a part number change from 88- to 89+. A magnet test is in order...

Last new one I bought which I'm assuming was an 92 was steel as I silver brazed a cap on a couple of the unused in AUS ports.