Engine/Transmission (1994 - 1998) Rerouting Heater Core Plumbing

[Vaughn MacKenzie]

Last time I was messing around under the hood of my '98 I got to thinking it would be nice to reroute the heater lines so they're under the exhaust manifold like the 24-valve trucks. It would make injector swaps a little easier, plus to me it looks kinda tacky to have them mounted above the manifold. It would definitely make it look cleaner.



Routing would be a little tricky but I think it's doable. The take-off and return points are different on the 12-valve so it's not as simple as swapping out for 24-valve heater tubes. But I think using heater tubes off a 24V and patching in pieces of rubber hose as needed would do the trick, as long as it doesn't look tacky or redneck engineered in the end :-laf



Anyone else consider doing this? When I tear my truck apart for a manifold & turbo upgrade later this year I might give it a whirl.



Vaughn

 

[JGK]

Vaughn,



I had this dilemma with my twins, largely due to the external waste gate now coming out of the top of the manifold. My approach was different than yours. Rather than try to route them out of sight under the manifold, which would put them closer to the heat of the twins, I routed them straight down the top of my valve covers, just to the left (passenger side) of the cover hold-down bolts. I replaced the hard lines with blue high temp silicon hose from the fire wall to the front of the engine. A little of the original hard lines were cut off and used for the final short section down to the lower connection by the water pump. I made a couple of stand-off brackets that mount to 2 of the cover bolts to hold the lines in place. Of course, you loose the use of the decorative valve cover name plate.



So far there has been no draw backs other than when it was real cold over night, when I started the engine in the morning and revved it a little, I could hear water coursing through the lines. Apparently the coolant must drain out of the lines over night because they've become the hight point of the system. That noise isn't heard any more now that it's starting to warm up.



It makes injector access real easy. Since the lines are flexible, valve cover access is easy because you can just push the lines off to the left out of the way.



However, I have these pretty, bright blue lines running down the length of the valve covers! But, hey, with dark purple powder coated cold pipes for the twins, what's a little more color, eh?



FWIW,

-Jay

 

[Hammer]

I have often thought of that myself and have even more since I did the Garrett Turbo as I only have one water line left on top. The other one goes throught the turbo center section and drops right to the return area already. The feed line coming off the thermostat area would be the one to move I just haven't figured a way to do that and not create a low spot in the line... ... ... Andy

 

[Vaughn MacKenzie]

Jay if you're going to the May 18th Dyno Day I'll have to take a look under your hood. I'm hoping to make it down for that.

Andy what would be the problem with a low spot, make it hard to reprime the system when flushing it?

 

[Swineheart]

Last time I was messing around under the hood of my '98 I got to thinking it would be nice to reroute the heater lines so they're under the exhaust manifold like the 24-valve trucks. It would make injector swaps a little easier, plus to me it looks kinda tacky to have them mounted above the manifold. It would definitely make it look cleaner.



Routing would be a little tricky but I think it's doable. The take-off and return points are different on the 12-valve so it's not as simple as swapping out for 24-valve heater tubes. But I think using heater tubes off a 24V and patching in pieces of rubber hose as needed would do the trick, as long as it doesn't look tacky or redneck engineered in the end :-laf



Anyone else consider doing this? When I tear my truck apart for a manifold & turbo upgrade later this year I might give it a whirl.



Vaughn

Hey Vaughn I have been thinking of the same thing the rubber is over due to be changed. The hoses have a little dip off of then so I think it's time for a cooling system overhaul. looks like I have my work cut out for me I'll let you know what I come up with. DEAN

 

[JGK]

Jay if you're going to the May 18th Dyno Day I'll have to take a look under your hood. I'm hoping to make it down for that.

I should be there!



-Jay

 

[Hammer]

Andy what would be the problem with a low spot, make it hard to reprime the system when flushing it?

Vaughn. .

The system already does the air gurgle deal due to the coolant ran through the charger housing after you change it. When the turbo was first installed it took along time to get all the air out of the system and for a couple of weeks afterward I was always checking the tank to make sure it wasn't low.



To drop the other line downward off the thermostat,then under the exhaust manifold and back up to the core I think it may allow a chance to air bind the system some. I think what I am going to do is run it from the housing to a remote coolant filter mounted on the side of my airbox and then back to the heater core and keep it level,just rerouted and out of the way... .....