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DIY: [Throttle Body Coolant Bypass]

68K views 75 replies 40 participants last post by  L3GDKANG/JDMKANG 
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#1 · (Edited)
DYI: [Throttle Body Coolant Bypass]



There has been some discussion in this thread about the throttle body coolant bypass.

This is a very simple DYI and almost anybody (within reason) can do it.

Tools:
10mm socket wrench
Philips head screw driver (optional)
Needle nose pliers
Bucket (to catch any coolant that comes out)

*Materials (note: my hoses were dry-rotted so I needed to replace them)
1) About 2 feet of 1/4" high temperature rubber tubing (available at most any hardware store or auto parts store).
-You can buy the pre-formed hose from Acura but the tube at a hardware store is about $0.49 a foot, you can't beat that deal.
2) Hose clamps (Just use the ones that are already located on the original hoses)

Basic procedure summary (further down is the detailed procedure with pictures):
1) Remove the intake
2) Remove the throttle body cable cover
3) Re-route the Idle Air Control (IAC) coolant line to the Throttle Body (TB) coolant out plug
4) Connect the TB "coolant in" and "coolant out" plugs together with 1/4" tubing.
5) Put the throttle body cable cover back on
6) Put the intake back in the car.
7) Start up the car and check for leaks.

If you already have a basic idea of what is going on with this tutorial, you can skip to step 3 of the procedure.

Procedure:
1) Remove the intake.

I have a CAI intake, so for anybody that has a factory intake, removing it is not hard. (Note, I don't know what all is needed to remove the intake from the legends with mas air flow sensors)
-Loosen the hose clamp that connects the intake to the throttle body with the 10mm socket.
-Disconnect the vacuum line and oil line from the intake.
-Remove the filter cover top and disconnect the resonator box (at least I think its a resonator box) from the radiator.
-Now the intake tube should just lift out.

You should see the following:


I'm pretty sure the Idle Air Control (BLUE) coolant line flows from out of the IAC into the base of the Throttle body. From there it heats the TB and flows back out of the TB and back into the engine block (YELLOW). (But its not real important which direction the coolant flows)

2) Remove the throttle body cable cover



3-4) This is the most important part.

Remove the 3 hoses from the bottom of the throttle body:


Coolant is going to come out, but not a lot. Its going to seem like a lot if you have never messed with the cooling system before, but don't worry you won't loose much. Just try to catch most of it in a bucket (to save cleanup time). If necessary check the coolant levels (once finished after you start the car to check for leaks) in the overflow tank and add any necessary coolant.

When removing the hoses, loosen the hose clips with the needle nose pliers. After you loosen the hose clamps, twist the hoses on the plugs with the pliers to un-stick the hoses, then simply remove the hoses.

Connect the IAC coolant line to the lowest plug on the throttle body (the one in the picture with the coolant coming out of it)

Simply connect the remaining two plugs together with a small piece of tube.

*If you buy new hoses, they may be hard to get onto the plugs, Just work with the hoses a little until they go on.




5) Put the throttle body cable cover back on
6) Put the intake back in the car.
7) Start up the car and check for leaks.
 
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#2 · (Edited)
Also, I needed all new hoses because the ones that were originally hooked up to the throttle body were leaking. You can do this DYI with out buying any new hoses. Instead of using a small piece of tube to connect the TB plugs back together, you can just re-route the existing tubes.

This is where my leak was:


Here is the replacement tube:
 
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#7 ·
lDneGeL said:
what exactly does this do?
It helps keep the throttle body cooler, by bypassing the coolant (heated by the engine). It just stops hot coolant from running through the throttle body to heat it.

Cooler air = More dence air

More dence air = more power.
 
#9 ·
Is it safe???

now i'm looking to do this on my car too, but was wondering if it's safe and reliable for our engines cuz' if it is why didn't the car come out of the dealer like this,will i be risking some reliability by doing this???
 
#19 ·
I did this tonight with the extra 10-15 mins I had. My friends and I have this "rail test" at a stop sign, we launch at the stop sign and at the end of the rail you clock your time, its almost an 1/8 mile. I got 70mph (stock KA8) compared to my past 67mph. My friends go 89mph (sr20 240sx), and 86mph (fully built h22 prelude). I recommend doing this hence it did make a difference for me. my .02
 
#22 ·
wolfalp said:
Has anybody tried to use a small cooler like a a/t cooler and an inline fuel pump to push the coolent? I have been reading the thread and it seems that the TB would not get hotter as the coolent heats up but could you actualy make it colder by pumping coolent from another source. Just a thought.
You know what, that's not a bad idea..... How about if I weld fitting on the TB coolant nipples and pump the CryO2 kit thru it as well as the intake and fuel bar??
 
#23 ·
when i fabbed the intake, i wondered about doing this since the vaccum line is connected to that tube where the coolant runs underneath.. but after careful thinking, or maybe just some hypothesis, doesn't the vacuum suck in cool air, run it across the top of the coolant line to lower the temp... i would think this would help the temp of the coolant running throughout the system even if it is just a little.. just a thought, or am i totally wrong???
 
#24 ·
HELP: TEMP GAUGE RISING

OK:
1. new engine installed. JDM 30K
2.New radiator
3. new radiator hoses
4.new battery
5.new fan control unit
_________________________________________________________________

Drove about 35 minutes to wok this morning. 5 mins before reaching work, i saw the temp gauge rise to the H level..then about2-5secs.dropped to normal. checked fans..they were not coming on. ?

Will change thermostat this afternoon, since i figur the new engine has the original one, also will change the CTS on the radiator..

HAS anyone had a faulty temp gauge, and any suggestions to why gauge still overheats?:(
 
#25 ·
vshiamsundar@aol.com said:
OK:
1. new engine installed. JDM 30K
2.New radiator
3. new radiator hoses
4.new battery
5.new fan control unit
_________________________________________________________________

Drove about 35 minutes to wok this morning. 5 mins before reaching work, i saw the temp gauge rise to the H level..then about2-5secs.dropped to normal. checked fans..they were not coming on. ?

Will change thermostat this afternoon, since i figur the new engine has the original one, also will change the CTS on the radiator..

HAS anyone had a faulty temp gauge, and any suggestions to why gauge still overheats?:(
if the thermostat is the original one on the JDM engine... then id suggest replacing it...your mechanic should have used some common sense... the engine only has 30k miles on it and seeing as how the thermostat is a critical part in your cooling system... i dont see why he didnt replace it to begin with...

btw i dont know why you posted in this thread
 
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