Double Aux Radiator Delete

**troyguitar** · 07-11-2013 06:36 AM

So I've read in separate threads that the passenger aux radiator can be deleted (i.e. JHM SC kit) with an additional small oil cooler added, then also that the driver's side aux radiator can just be completely deleted with nothing in its place - supposedly to no ill effect. Is the second one true? There did not seem to be much consensus on that or discussion of any kind, really.

If so, could BOTH aux radiators be deleted (plus oil cooler added)?

This would make the task of creating front brake cooling ducts easier (plus save some weight in the front end), but obviously compromising engine bay component cooling to help brake cooling is not acceptable.

**KAL** · 07-11-2013 09:10 AM

Doesn't the 4.2 get a little heat soaked? And wouldnt the removal of these rads effect that?

**troyguitar** · 07-11-2013 09:18 AM

AFAIK the heat soak is only the intake getting up to the coolant temp, should be unrelated to the rads unless coolant temp is not able to be maintained without the aux rads (which is the whole question here). I could be missing something but that is my understanding.

**mad70sx** · 07-11-2013 10:07 AM

I believe that you could get away with one not on the car,probably not both. There have been a few posts about removing one of them after it started to leak,with no ill effects. Have not heard of anyone removing both. That sounds a bit sketchy to me. They're there for a reason.

**BCsniper** · 07-11-2013 10:09 AM

B6Joe claimed you could probably get rid of both will no ill-effects when he got rid of his driver's side rad.

**troyguitar** · 07-11-2013 11:04 AM

Originally Posted by BCsniper

B6Joe claimed you could probably get rid of both will no ill-effects when he got rid of his driver's side rad.

Yep, that is the most discussion I have seen on the subject and why I decided to make the thread - was wondering if anyone has tried it or thought about it any further than that.

**Kookie** · 07-11-2013 11:40 AM

Is anyone out there running the JHM S/C & has their driver side radiator deleted?

I'm curious about this as well.

**Dirtracer603** · 07-11-2013 12:47 PM

It's my understanding that one was an oil cooler that always an open circuit. The other was a supplimentary radiator that actually was coolant temperature actuated (It was closed until additional cooling was needed). If you lived in a colder climate or always drove highways you could probably get by just fine without either.

**jr1415us** · 07-11-2013 01:44 PM

Leave them there. How hot are you really going to get your brakes anyway? An engine running too hot is far worse

**mgikone69** · 07-11-2013 01:47 PM

playing devils advocate, but with the removal of the extra radiator(s) wouldnt that decrease the amount of coolant/water circulating the engine and rad....that cant be too good right. Living here in S.Fl i wish i could add a radiator lol, or a larger one

**troyguitar** · 07-11-2013 01:49 PM

Originally Posted by jr1415us

Leave them there. How hot are you really going to get your brakes anyway?

Ridiculously hot, it weighs 4000 lbs and I'm going to run it on race tracks with sticky tires and track-specific brake pads...

**BCsniper** · 07-11-2013 01:52 PM

Originally Posted by jr1415us

Leave them there. How hot are you really going to get your brakes anyway? An engine running too hot is far worse

^^^
I have to beg to differ. If you're engine gets to hot, you wont be going anywhere. If you're brakes get too hot you wont be able to keep yourself from going somewhere.

**WolfS4** · 07-11-2013 04:02 PM

Try it and see.

I've contemplated it before. The JHM oil cooler kit is meant to replace your pass side aux rad, and the drivers side rad is only used when temps reach a certain point and has its own aux coolant pump. While you are in there delete your SAI. You would be reducing your coolant capacity, but increasing your oil capacity slightly and in some ways reducing some of your under the hood temps and freeing up some space. Maybe add a cf vented hood too. All of that would probably drop 70-100lbs of weight off the nose.

**jr1415us** · 07-11-2013 04:41 PM

Originally Posted by BCsniper

^^^
I have to beg to differ. If you're engine gets to hot, you wont be going anywhere. If you're brakes get too hot you wont be able to keep yourself from going somewhere.

Is the car being used in such a way that added brake cooling ducts are actually necessary? Or is this just a " I have a race car" thing.

**troyguitar** · 07-11-2013 05:37 PM

Originally Posted by WolfS4

Try it and see.

I've contemplated it before. The JHM oil cooler kit is meant to replace your pass side aux rad, and the drivers side rad is only used when temps reach a certain point and has its own aux coolant pump. While you are in there delete your SAI. You would be reducing your coolant capacity, but increasing your oil capacity slightly and in some ways reducing some of your under the hood temps and freeing up some space. Maybe add a cf vented hood too. All of that would probably drop 70-100lbs of weight off the nose.

Awful expensive just to try it and see at $900 for the oil cooler kit, maybe next year. What is SAI?

Originally Posted by jr1415us

Is the car being used in such a way that added brake cooling ducts are actually necessary? Or is this just a " I have a race car" thing.

Originally Posted by troyguitar

Ridiculously hot, it weighs 4000 lbs and I'm going to run it on race tracks with sticky tires and track-specific brake pads...

**WolfS4** · 07-11-2013 06:20 PM

The JHM oil cooler kit is designed to replace the passenger side aux rad. So that eliminates one of your aux rads and just leaves the drivers side aux rad which it seems others have done already.

The SAI = secondary air injection. It's basically an air pump to bring your catalytic converters up to temp quicker on cold starts. Takes up a bit of space/weight just behind one of the aux radiators. You will get a code, but it can be tuned out.

**Eye_In_The_Sky** · 12-14-2018 12:34 AM

Anyone that deleted the radiator and did not run the oil cooler kit? and just used this https://jhmotorsports.com/jhm-cap-an...hain-4-2l.html

**Mr.Jetta** · 12-14-2018 11:32 AM

I have two questions:
1) Do we know what the trigger temp is, or conditions that need to be met, for the aux pump to allow flow to this rad? If you run a warning light, for 5-10degrees before this trigger, you could operate safely, without the rad.
2) Are any upgrades available for the main radiator on our cars? If one were to delete the DS-Aux Rad, but could upgrade the main unit at the same time, that might be enough to offset the loss of the DSAuxRad.

I like the idea of deleting things, especially for the sake of simplicity. But it was put there for a reason, the insurance risk of a hot motor, and loss of overall coolant capacity, etc, make this one a tough thought for me. But Maybe, by using either of the two ideas above, it can be managed effectively so that the OP can still get his weight redux, brake ducts, and simplified setup done.

EDIT - It just dawned on me that some of the mkiv vw and other cars of this era also had aux rads, a lot of which are deleted without ill effects. Another thing to check would be if this aux rad is designed to operate not just when overheating, but for HVAC management, cool-down once the car is off, etc. Some cars run aux pumps to keep coolant flowing at low rpm when the water pump cannot circulate fluid but heat is needed in the heatercore. You may be sacrificing more than just overheat management with the proposed delete. My best advice is to understand if/when and why this aux setup is used, and then determine if you can justify how to manage it being gone. !

**Terry.Reese** · 12-14-2018 03:49 PM

Originally Posted by Mr.Jetta

I have two questions:
1) Do we know what the trigger temp is, or conditions that need to be met, for the aux pump to allow flow to this rad? If you run a warning light, for 5-10degrees before this trigger, you could operate safely, without the rad.
2) Are any upgrades available for the main radiator on our cars? If one were to delete the DS-Aux Rad, but could upgrade the main unit at the same time, that might be enough to offset the loss of the DSAuxRad.

I like the idea of deleting things, especially for the sake of simplicity. But it was put there for a reason, the insurance risk of a hot motor, and loss of overall coolant capacity, etc, make this one a tough thought for me. But Maybe, by using either of the two ideas above, it can be managed effectively so that the OP can still get his weight redux, brake ducts, and simplified setup done.

EDIT - It just dawned on me that some of the mkiv vw and other cars of this era also had aux rads, a lot of which are deleted without ill effects. Another thing to check would be if this aux rad is designed to operate not just when overheating, but for HVAC management, cool-down once the car is off, etc. Some cars run aux pumps to keep coolant flowing at low rpm when the water pump cannot circulate fluid but heat is needed in the heatercore. You may be sacrificing more than just overheat management with the proposed delete. My best advice is to understand if/when and why this aux setup is used, and then determine if you can justify how to manage it being gone. !

I just have the aux radiator deleted, did nothing with the oil cooler.