Rear Coolant Hardpipe Leak?

[Mikael_7m]

Hey guys, I believe that the rear coolant pipe is leaking on my car. I replaced every coolant hose there is, back there and its still leaking which leads me to believe its the hardpipe.
I can't see behind the motor well enough to confirm it 100% but if it is the problem what are my options? It seems impossible to get to.

Or do you guys reckon it could be that coolant plug?

 

[Poodles]

Only way to get that pipe out is to remove the engine

 

[gats]

Does yours have the rubber blanking cap on inlet side as shown?
If so, that will more than probably be leaking... At least tha can be replaced in-car!

 

[max-89supra(t)]

I have a good coolant hardline I could sell you if you needed one, pm me if you do.
By the way, I thought it was possible to take the hardline off with the exhaust manifold off, or am I wrong? I don't have a supra anymore so I don't have a motor to look at.

 

[Mikael_7m]

Gats, mine has a hard plastic bung style plug which is like hammered in from factory. Not like the one pictured. I've also checked it for leaks.

Does anyone know why that pipe wraps around the back of the block, just to be blocked of?

 

[gats]

Hmm, OK well hopefully that's one leak point ruled out!
Have you checked/replaced the 2 copper washers on the heater union at the back of the head?

Pipe does this as it is the same 'base' design for both LHD & RHD cars, with just the heater matrix inlets/outlets being swapped.

 

[Mikael_7m]

Not sure what the heater union is... :/

 

[3p141592654]

Its the giant banjo assembly on the head that leads to the heater valve on the firewall. See 16268 in the EPC below. I would not recommend replacing it unless you are prepared to pull the head if things go badly (like it breaks off in the head as it commonly does).

http://www.cygnusx1.net/Supra/Library/EPC/291420/catalog.aspx?F=1603&P=1

 

[Poodles]

Also, it shouldn't leak unless it's been disturbed. The hardline around the back of the block can rust out internally though

It comes around the side and feeds coolant to the throttle body and ISCV.

 

[Mikael_7m]

The heater union does not appear to be leaking. I stuck my finger back there at it was dry after a run. Definately seems to come from the hardpipe. Damn, so my only option is to remove my motor....
What a terrible design flaw!!

p.s. thanks for your help guys

 

[Poodles]

IF you can find the hole, and clean it well, you could band-aid it with jb-weld and a hose clamp... Not the best solution, but I've seen it work in the past on other cars...

 

[Mikael_7m]

Good idea Poodles, I'll give that a try first!

 

[CyFi6]

Or option number 2 snap off the small metal hardline for the throttle body/iscv and weld up the remaining hole on the new one. This pipe is the only thing I am aware of that prevents you from being able to slide it out with the head on. If you are in a climate where it gets below freezing though, you probably don't want to bypass the throttle body/iscv coolant.

On the other hand have you verified that the leak is from the coolant pipe? Its possible you have a leak from the head gasket or even the freeze plug back there.

 

[mk3tattoos]

IF you can find the hole, and clean it well, you could band-aid it with jb-weld and a hose clamp... Not the best solution, but I've seen it work in the past on other cars...

I did this on my last 7m motor and it worked great!!!

 

[Mikael_7m]

On the other hand have you verified that the leak is from the coolant pipe? Its possible you have a leak from the head gasket or even the freeze plug back there.

I have not 100% confirmed it to be the hardpipe. Im gonna get hold of a small mirror to have a look back there. That leaking head gasket possibility, is rather worrying for me.


EDIT: So I got a mirror behind there after a short drive and it was in fact my greatest fear... There is coolant seeping out between the head and the block. All I can say is SHIT! Gotta get my built motor done asap!

 

[Mikael_7m]

its odd that it didn't leak on the inside and mix with the oil like every other BHG...