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Discussion Starter #1
I'm in the midst of a splitport swap and I have been tracing coolant hoses in my intake manifold.

On both the singleport and splitport intake manifolds, I see there's a hard pipe that runs from the front of the intake manifold, through the heater core, and back into the rear of the lower intake manifold.

Q: Since I don't have a heater core anymore, can I just cap off the front and rear ports of the intake manifold or for coolant flow reasons, do I need to run a hose from the front port to the back port?

Thanks in advance for your advice.

Regards,
-g
 

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I'm in the midst of a splitport swap and I have been tracing coolant hoses in my intake manifold.

On both the singleport and splitport intake manifolds, I see there's a hard pipe that runs from the front of the intake manifold, through the heater core, and back into the rear of the lower intake manifold.

Q: Since I don't have a heater core anymore, can I just cap off the front and rear ports of the intake manifold or for coolant flow reasons, do I need to run a hose from the front port to the back port?

Thanks in advance for your advice.

Regards,
-g
I believe you at least need the pipe for proper coolant circulation with or without the heater core plumed in, however, on a 24hrs of lemons car why not run bulk heater hoses to a remote heater core in the stock battery area with a small fan (off of a wrecked toyota truck transmission cooler for ex.), cut a hole similar to the air box hole for air to flow across it, sort of like an aftermarket trans cooler only it's basically an auxiliary radiator setup, I'd think that would be helpful for keeping it cool. Just a crazy thought though.
 

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Discussion Starter #3
I believe you at least need the pipe for proper coolant circulation with or without the heater core plumed in, however, on a 24hrs of lemons car why not run bulk heater hoses to a remote heater core in the stock battery area with a small fan (off of a wrecked toyota truck transmission cooler for ex.), cut a hole similar to the air box hole for air to flow across it, sort of like an aftermarket trans cooler only it's basically an auxiliary radiator setup, I'd think that would be helpful for keeping it cool. Just a crazy thought though.
Not a bad idea but we haven't had any cooling problems to merit an auxilliary radiator. Our battery is relocated so it would be a matter of fabricating a mounting bracket. I have heard that some cars need such a bypass for proper circulation - hence my question.

Any other opinions?
-g
 

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Run a 180 degree hose from the top hard coolant line to the lower coolant line in the intake manifold.
 

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It goes to the back of the intake ? I have only seen that on the 4.6L engines. The 3.8 SC and 3.8 NA's I have here route the cooalnt return to the water pump. On the 96/97 NA here, coolant goes from the bypass hose in the intake manifold, to the heater core and back to the water pump T which is split off to the other end of the crossover also. The SC has the coolant go from the upper intake crossover, heater core, around the engine to the oil cooler, and back to the water pump.

The coolant flows from the water pump, to the block, through the cylinder heads and to the crossover tube in the intake manifold. From there, it goes back to the water pump or circulates through the radiator if the T-stat is open.

Capping them off may slightly decrease the volume of water / coolant flowing but when the thermostat is open, its pulling a larger volume through different openings anyways ( Water outlet / T-stat location to the radiator upper, through the radiator, and into the lower outlet / inlet to the water pump ) . On the 3.8 The heater core is not necessary to complete a coolant circulation. Any of the ports on the intake manifold crossover are outlets .. the inlets are on the water pump, forward of the gasket and the water pump pushes water through the block.
 

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^^^Word. Capping them off would probably be ok, but I would feel better hooking them together. IIRC, there is the bypass pipe from the water pump and the other hose from the heater core goes to the pipe that has the coolant bleed screw on it. If you hook those two together you should be in business, except no heat for your race car :(
 

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Yeah I looked at the pictures Baybird posted in your other thread .. I see the intake tube now .. so that goes through the intake manifold, back to the crossover section ??
 

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Discussion Starter #8 (Edited)
I think i misspoke earlier; the line from the heater core goes to a pipe that goes over the lower intake manifold and back into the water pump.

I have a few more questions if you guys don't mind:

1) Is the hard pipe labeled what you guys are referring to as the "crossover pipe"?
1b) No matter what it is called, is there a trick to removing it from the water pump? I have it unbolted and have tried tugging on it. Do I need to pry it up or something?


2) I studied all of your comments at work and worked on the car some more this evening. I'm no artist but I mocked up the following drawing for the coolant flow through the 3.8L engine. I tried putting things in position relative to each other and drew little arrows indicating flow direction. Do I have the flow of coolant indicated correctly here? If not, please correct me so I understand what's going on in the system.
*updated with SCTbird1994's corrections*


3) Finally, in an somewhat unrelated related question, is there a trick to detaching the dipstick so I can take off the driver side exhaust manifold? Is it something I have to unbolt from below the car?

Thanks so much for all your answers, guys. I promise to compile it all in a single splitport DIY once I'm done. I also found my new favorite specialty tool from HF:
http://www.harborfreight.com/8-inch-radiator-hose-pick-96572.html

Regards,
-g
 

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The pipe should just pull out once its unbolted but you might have the pry it. There's an o-ring in there that's probably all gunked up.

If you dont have the splitport hard coolant line none of this is going to make sense. The splitport line goes around the intake manifold all the way to the back of the engine where it sits parallel to the lower intake manifold coolant inlet. So like i said before, get a good 180 degree coolant hose to by pass the heater core. For maximum cooling, I wouldn't by pass the two inlet/outlets in the splitport lower intake manifold.
 

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Discussion Starter #10
The pipe should just pull out once its unbolted but you might have the pry it. There's an o-ring in there that's probably all gunked up.

If you dont have the splitport hard coolant line none of this is going to make sense. The splitport line goes around the intake manifold all the way to the back of the engine where it sits parallel to the lower intake manifold coolant inlet. So like i said before, get a good 180 degree coolant hose to by pass the heater core. For maximum cooling, I wouldn't by pass the two inlet/outlets in the splitport lower intake manifold.
Got it. I have the hard coolant line so I'll use it. I also believe i need it because it will be the highest point in the coolant system and has the air bleeder bolt built in.

I'm wondering a little how all this stuff will fit together up front with the distributor in its factory location and and the fuel pressure regulator relocated to the front of the intake manifold.
I'm ditching the EGR but will use the A shaped piece as my 89SC came with a blockff plate that exactly matches where the EGR bolts in. If that doesn't work, I'll cut up the A-shape and sandwich some metal plate inbetween and use that as a block.

Tomorow I'll rebuild the 14# injectors for use w/ my spare engine + attack the exhaust manifolds.
 

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1. heater core bypass tube. The Crossover is the section on the Intake manifold the coolant flows through from the heads back to the water pump.

1b. Ive had some of those get very stuck, pry with a flathead screwdriver or something for leverage, might need to twist and wiggle it .. they can be a pain to get off / out.

2. The radiator lower outlet goes to the Water pump, not the engine block but everything else looks to be correct.

3. Oil dipstick tube can be in there tight also, its only bolted to the exhaust manifold stud. No O rings, its just a tight fit. Be careful removing it, you dont want to have it break off during removal, then you need to drop the oil pan and hammer it from the bottom out. If you can twist it slightly / wiggle while pulling up, it should come out.
 

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Got it. I have the hard coolant line so I'll use it. I also believe i need it because it will be the highest point in the coolant system and has the air bleeder bolt built in.

I'm wondering a little how all this stuff will fit together up front with the distributor in its factory location and and the fuel pressure regulator relocated to the front of the intake manifold.
I'm ditching the EGR but will use the A shaped piece as my 89SC came with a blockff plate that exactly matches where the EGR bolts in. If that doesn't work, I'll cut up the A-shape and sandwich some metal plate inbetween and use that as a block.

Tomorow I'll rebuild the 14# injectors for use w/ my spare engine + attack the exhaust manifolds.
Making everything fit is the hard part but is definitively doable with some creativity. As you've probably seen while researching splitport swaps that they're never exactly the same. Each one has a unique modified part to make the swap work.
 

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Discussion Starter #13
One more question guys about the o-rings around the coolant tubes.
I figure i should replace them in order to minimize the possibility of leaks. From what I can see here, they will get exposed to coolant at engine temp.

Q: Do I need to buy some specific orings from the dealer, can I just pick them up at autozone, or will any o-rings of the right size from the plumbing section of Lowes will do?

My first inclination would be to go with option 3 (Lowes) but I just wanted to get some suggestions here.
Regards,
-g
 

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One more question guys about the o-rings around the coolant tubes.
I figure i should replace them in order to minimize the possibility of leaks. From what I can see here, they will get exposed to coolant at engine temp.

Q: Do I need to buy some specific orings from the dealer, can I just pick them up at autozone, or will any o-rings of the right size from the plumbing section of Lowes will do?

My first inclination would be to go with option 3 (Lowes) but I just wanted to get some suggestions here.
Regards,
-g
They're not available at the dealer or at least weren't when I tried to buy some. Im using the ones from AZ and they work fine, no leaks. They should be fine for coolant, fuel and A/C have their own type of o-rings.
 
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