# DIY: AEG Throttle Body Coolant Bypass



## twicepardoned (May 2, 2006)

DIY: 
Throttle Body Coolant Bypass
Pros: http://****************.com/smile/emthup.gif 
Less hose and Cleaner look
Cooler Intake temperature








Cons: http://****************.com/smile/emthdown.gif 
Sticky Throttle during below freezing start ups








Overview:
The Throttle Body water passage was designed for below freezing temperatures during morning start ups. It should be noted that these are COMPLETELY unnecessary on turbo charged applications and IMO only slightly necessary during NA vehicles. The idea was that the throttle gets junked with oil or grease and when at freezing temperatures the Throttle plate gets 'stuck' in an open position. On cars without the water passages this is simply overcame by 'pumping' the pedal once or twice. It is unlikely to happen but with any modifications you assume your own risk and nor I or this forum are responsible for your decisions.
Personal Experience:
I have never had a problem on my previous cars with this modification. I have done it simply as a small and unoticeable modification. I do approach performance with the mind set of "Everything counts"... even removing windshield wiper or cutting sheet metal to drop weight.
This modification will only drop the intake temperature by eliminating the Hot coolant from running through the water passages in the TB. It sounds almost backwards, because coolant 'cools' but in this case it was designed to heat. The temps of the coolant are higher than the TB by itself, so it heats it. The cooler TB will pass cooler air, not by much BUT again... Everything counts.








Tools:
Pliers
New heater Hose
Step One:
Drain the coolant or be prepared for it to go everywhere.
Step Two:
Remove the Coolant Hose from the following 4 locations:
1-Throttle Body (2)








2-Feed line from a Major heater hose above the transmisson (1) This hose feeds into a T fitting just remove the line going to the TB.








3-Major heater hose by firewall (1)








4-From the Hose going to the Reservoir across the top of Firewall (1)









Step Three:
Plug The Nipple from the hose you removed by the firewall








Step Four:
Cut new hose to length need to connect T fitting (A) to the hose running across the top of firewall (B)
Attach and tighten the hose.








This is all there is to it. I'll have to add a pic later of what it looks like with the head on my car. I just happen to do this while my cylinder head was out.
Now don't go jumping in your car and take off down the street expecting some major difference.








Enjoy!









_Modified by twicepardoned at 9:22 PM 6-23-2008_


_Modified by twicepardoned at 9:24 PM 6-23-2008_


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## vasillalov (Nov 5, 2003)

*Re: DIY: AEG Throttle Body Coolant Bypass (twicepardoned)*

Amazing!
I did that same exact mod last night! I was getting ready to post my DIY here!


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## the_q_jet (Mar 19, 2005)

i just took mine and routed them to the turbo


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## twicepardoned (May 2, 2006)

*Re: DIY: AEG Throttle Body Coolant Bypass (vasillalov)*


_Quote, originally posted by *vasillalov* »_Amazing!
I did that same exact mod last night! I was getting ready to post my DIY here!

Seriously??? That is crazy
I actually did it quite awhile ago but all I did was plug the hose with a bolt. This way it's clean and one less hose and T-fitting.


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## twicepardoned (May 2, 2006)

Once I put the turbo in I'll T it off again but I don't imagine I'll have all the mony and parts till Spring. In fact my Trans swap will probably happen before my Turbo goes in.


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## twicepardoned (May 2, 2006)

*Re: (twicepardoned)*

How come this never got added to the DIY list??? hmmm I could have swore I reported it... maybe someone else needs to report it???


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## vasillalov (Nov 5, 2003)

*Re: (twicepardoned)*

Let me see what I can do about this.


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## twicepardoned (May 2, 2006)

hey hey... You can still keep your reign as the DIY king! hehehe


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## batcat420 (Mar 15, 2006)

*Re: DIY: AEG Throttle Body Coolant Bypass (twicepardoned)*

Very cool. I'll be doing this soon when I do my water pump. http://****************.com/smile/emthup.gif


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## twicepardoned (May 2, 2006)

*Re: DIY: AEG Throttle Body Coolant Bypass (UFC_Champ_Scott)*

http://****************.com/smile/emthup.gif


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## d1rty2.0 (Jun 16, 2008)

*Re: DIY: AEG Throttle Body Coolant Bypass (twicepardoned)*

The pictures are not available anymore, hope u can work on that for me please. And by the way I completely agree with you! Everything counts... even me working out to lose that 'extra weight' ha thanks! l8r http://****************.com/smile/emthup.gif


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## twicepardoned (May 2, 2006)

Fixed...
I had sorted my entire photobucket and apparently the 'link' changes as a result.


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## d1rty2.0 (Jun 16, 2008)

*Re: (twicepardoned)*

hey thanks man! I just went to the dealership to get the flange, some coolant and I'm ready for this and a good o' flush! Once again, thank you! http://****************.com/smile/emthup.gif


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## twicepardoned (May 2, 2006)

No problem, I should be fixing the other DIYs tonight, I just can't access my photo bucket from work... dang Blockers!


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## skatedvs420 (Dec 23, 2004)

*Re: DIY: AEG Throttle Body Coolant Bypass (twicepardoned)*

I DONT HAVE A COOLANT LINE ON MY TB...


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## Jay-Bee (Sep 22, 2007)

*Re: DIY: AEG Throttle Body Coolant Bypass (skatedvs420)*


_Quote, originally posted by *skatedvs420* »_I DONT HAVE A COOLANT LINE ON MY TB...

Is it a MK4 2.0??


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## hfiles2011 (Dec 5, 2011)

skatedvs420 said:


> I DONT HAVE A COOLANT LINE ON MY TB...


aeg only holmes:laugh:


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## Vandy99 (Sep 28, 2010)

I've done the tb by pass and also ported it out and made a custom cold air intake and I love it. The car definitely had a Lil more pick up to it.


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## timeout88 (Oct 3, 2016)

*AEG Throttle Body Coolant Bypass*

Hi I have a 2003 1.8T new beetle, and I wonder if you can share the picture again. Thanks for your help


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