That damn hardpipe.

[Doward]

Yeah, I sandblasted down the cooling hardpipe that runs along under the exhaust, and well - it looks like shit. It's heavily corroded, and I'd rather not take the chance of springing a leak.

I'm debating either buying a brand new one from Toyota, or just building my own, using the old one mainly as a flange, and running new SS braided lines.

Thoughts?

 

[Justin727]

I had one spring a leak on me at the flange. I had to cut it apart rebraze it to the flang and connect it using some high strength spring wrapped hose. Marine hose.

Anyhow find a new one and powder coat it or just do SS lines.
I was lucky to have a spare one without any corrosion so I cleaned it up and coated it for protection.

 

[upgradedsupra]

Buy new

 

[MDCmotorsports]

Buy new or build some out of ss line...

 

[lagged]

i have a few in excellent shape.

 

[Doward]

Now here's a crazy thought:

http://www.cygnusx1.net/Supra/Library/EPC/291420/catalog.aspx?F=1603&P=2

That top pipe (it is 2 pipes together) runs from the thermostat housing to the water nipple at the back of the head - obviously, helpful.

The bottom pipe, on the other hand, just runs from the flange, around the engine, to the throttle body coolant bypass.

If I'm not even using the throttle body coolant passages, why can't I just run the top pipe, and build a flange to just block the bottom pipe completely - eliminating it?

 

[shaeff]

i wonder what type of cooling that small line offers when it enters back in through the head via that small nipple on the lower intake manifold, as well as if that's needed to keep the coolant circuit operating smoothly...

 

[joliroger4]

i wonder what type of cooling that small line offers when it enters back in through the head via that small nipple on the lower intake manifold, as well as if that's needed to keep the coolant circuit operating smoothly...

You can plug it or loop it to the nipple on the lower intake manifold. Neither will cause any kind of issue.

 

[cuel]

Doesn't the t.b. coolant line also go to the isc valve, and then loop down into the head around cyl. 2 or 3 at the bottom of the intake? Or is that just on the N/A?

 

[NJsupraA70]

The main coolant bypass pipe should always be replaced. Dont cheap out. I believe it was about $100-120 from champion.

 

[joliroger4]

That's correct. By plugging or looping this line you are no longer running coolant through the ISC and TB. It's to prevent icing in both. Unless you live in the extreme cold, you really don't need this.

 

[cuel]

lol, yeah. I repeated what you said. I got side tracked by the t.v. for a few minutes and missed your post.

 

[Doward]

The main coolant bypass pipe should always be replaced. Dont cheap out. I believe it was about $100-120 from champion.

The main bypass pipe is the upper of the two - I wouldn't be eliminating that.

The bottom flanged one, is the one I would eliminate, since there is zero circulation (tb coolant is bypassed) in my setup.

 

[shaeff]

You can plug it or loop it to the nipple on the lower intake manifold. Neither will cause any kind of issue.

oh i know that, as mine's been looped from the hardpipe back to the nipple for years.

i was curious if it would hinder flow, or result in a loss of cooling to the #2/3 cylinder section of the head.

i'd rather stick a small coolant filter in there, and have it act as a bypass setup than block it off completely. i just haven't gotten that far yet.

 

[shaeff]

bumping this, just to throw this in there for everyone's reference.

 

[Doward]

OK, so I can't eliminate the bottom line. Forgot about the heater :3d_frown:

BUT - it is a 5/8" tube. I can get 25' roll of 5/8" aluminum tube from Summitracing.com for $27

 

[IJ.]

Just buy a new Toyota one it'll be good for another 20 years if you keep the correct coolant in the motor (which you will no doubt)

 

[shaeff]

yeah, Doward, i re-read what you wrote, and thought to myself:

"what is he planning to do about the heater core return?"

i figured that i just mis-read or misunderstood something, and posted the pic simply for reference.

 

[Doward]

I appreciate the pic. With the car apart, I never even thought of it - I only looked at the heater pickup, and not the return.

That said, I do believe I'm still going to build my own. I don't want the extra nipples just capped off, as they are possible failure points, imho.

Top pipe will run up to the union (still need to order a new one - don't want the old, rusted one) and the bottom will run around the block, to the heater inlet.

Besides, building a new set of pipes from aluminum will prevent them from ever rotting out again Also give me a chance to convert everything over to AN fittings.

 

[Poodles]

thought that upper one was the bypass for the coolant system when the T-stat is closed...