Coolant Hardline removal?

[americanjebus]

So I had my car overheat on me 2 years ago and decided not to even bother with the car for a while. Well now I have some time on my hands to do some work and i've run into an issue.

The seals on the water pump were blown from the air pressure that got into the coolant system so i've got a new water pump and gasket ready to go in. When the car overheated i had steam bubbling from the gasket on the water pump and a tiny little stream of steam coming from behind my exhaust manifold heat shield.

I've narrowed it down to this part #16268
http://www.cygnusx1.net/Supra/Library/EPC/291220/catalog.aspx?F=1603&P=2

Its the coolant hard line running underneath the manifold. My assumption is that its been getting so hot with my under hood temperatures that it finally cracked and is letting air into my coolant system.

the part is a good $240 new from Toyota, and looking at the diagram its a single hard line assembly wrapping around the block.

Question: How the hell am i supposed to get it out? It looks like I have to take the exhaust manifold, intake, and rear heater hoses off. If its a minute crack can I weld? I want to either fix the crack or get a new piece and insulate the side exposed to heat.

Suggestions, experience?

 

[IBoughtASupra]

It runs on the exhaust side around the block. There is an outlet there going to the intake manifold to let anti-freeze into the thorttle body and ISCV for colder temperatures. You can cut off the old line but you will need to remove the intake manifold to properly install the new one.

 

[ben1984j]

If I remember right...there are two bolts holding it onto the block, then two nuts where it mates to the housing behind the water pump. Then on the intake side it just has a heater hose clamped onto it.

I had to take mine out (or just move it around some) to replace that gasket at the end of it...at the time the head and both manifolds were removed....but in your situation I'd think the most you'd have to do is remove the exhaust manifold. The intake looks like it's far enough out of the way...

But I have to wonder if this part is really your problem. For one thing, I've never heard of it cracking due to excessive heat...if this does happen, it's very rare. Also, I don't see how a leak would let excess pressure into your cooling system? The cooling system is kept under constant positive pressure by the radiator cap, so if anything wouldn't a leak in this pipe cause a loss of pressure?

On the other hand, a blown head gasket (between water jacket and combustion chamber) will add excess pressure to the cooling system...did the head gasket show any signs of such damage when you took it out?

 

[americanjebus]

I ran a block test to begin with just to make sure it wasn't the head gasket. If the head gasket had gone out then i would have picked up a CO2 reading in the coolant system but it came out clear. Also I know there was steam coming from underneath the exhaust manifold and this is the only line I see that could have leeked air, I'm guessing the crack is really really small because it only showed up under extreme heat and after doing some really long hard pulls on the highway in 105 degree weather.

I know where it all mates up and connects i've been poking around all day but i cant figure a way to get the damn thing out without taking pretty much everything off of the head.

 

[GrimJack]

It's possible to pop a head gasket from the coolant passage to the outside of the block, which will leak coolant in the area you mentioned when under pressure (hot) and suck in air when under vacuum (cooling down). This doesn't allow exhaust into the coolant, (or coolant into the cylinders, for that matter) so it will still pass the block test.

 

[americanjebus]

It's possible to pop a head gasket from the coolant passage to the outside of the block, which will leak coolant in the area you mentioned when under pressure (hot) and suck in air when under vacuum (cooling down). This doesn't allow exhaust into the coolant, (or coolant into the cylinders, for that matter) so it will still pass the block test.

Yea i've seen this happen once. I dont drive the car, and haven't for like 2 years so im just going to finish up what I can and wait and see what exactly is the next part of the coolant system that blows out. Either way, be it the head or the pipe all that crap is going to have to come out. I have no mixture of coolant and oil, or coolant into the cylinders so im just going to wait and try to pin point exactly where this is coming from. The car made it 250 miles like this with just water and no issues and I really just need the car in a condition to get from point A to point B in case I move so we'll see how it goes after i finish this 1st part up

 

[Drake69]

Subscribed. I'm looking into replacing my water pump and am researching what else I may have to tackle to get this car back to DD status.