Bleeding Heat Exchanger,and Super charger

[stevemannn]

So figured this could help some people out.

i had crazy high AIT's even after vacuum bleeding,and trying to manually bleed the car by hand.
sent my logs to IE, and they were seeing up to 90C in a 1/4 mile.

they told me, they start to pull back timing, and power at 70C
so 70C is the magic number i am aiming for.


yesterday, i was bleeding it by hand again the old school way. loostening the bleeder screws, bleeding the heat exchanger (mine is mercracing)
but it was making a mess, and its really hard to tell how much air is really in the system like this.

i took it for a quick pull, and from the bottom of 3rd gear to the top. i went from 30C to 66C.

still not good enough or even close.

so i spent all night thinking about how to do this the old school way. with a funnel or a tube of some sort.

for some reason this popped into my head
its a hair dye applicator bottle. they can be had for like $2
and can get them at any beauty supply store or walmart etc.

https://www.sallybeauty.com/hair/hair-color/hair-color-accessories/applicators/calibrated-applicator-bottle/SBS-305924.html?list=Home%7CSalon

https://imgur.com/a/9fG1vRJ


i just drilled the nozzle out a bit, and stuck it right in the heat exchanger, and well... the video will show you just how much air i had in there.
also there is no mess at all, and you can actually see when the bubbles stop.

another great thing. it fits right in the supercharger bleed holes. so you can pull the screws completely out.
cycle the pump, and watch and see the coolant and air come out. (this is a two man job though. that little bottle filled up fast. might be easier with a bigger bottle, and i will probably try it)
just make sure to shut the pump off, or you will have a mess.


https://youtu.be/fFeVmsh8UPg


but i had that bottle on the bleeder for the heatexchanger for about an hour. with the front end in the air. the amount of air i got out of the system is amazing.
i still might have a bit trapped in it, but i will check when i get another chance.

so i went for a drive to test it,and log. looking to see when i hit that magic number 70C

same thing as before. bottom of 3rd gear around 30C
i didnt hit 70C till the top of 4th. which is a huge difference from before.

i have not gotten a chance to get to the track, but i have a feeling my times,and trap will be much better.

I hope this helps anyone having trouble, or anyone who doesnt want to create a mess everywhere.

[theweebabyseamus]

It odd, it seems like anytime I hear about a HX not bleeding correctly its a Merc...

[2by2handsofblue]

It odd, it seems like anytime I hear about a HX not bleeding correctly its a Merc...So dont get a HX that's merc made. They do have good deals but I guess that comes at a price.

I'm looking at other companies HX, and it seems they are double the price. So I guess theres a reason.
But I'm new to the game so I just heard about merc on this forum

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[2by2handsofblue]

So figured this could help some people out.

i had crazy high AIT's even after vacuum bleeding,and trying to manually bleed the car by hand.
sent my logs to IE, and they were seeing up to 90C in a 1/4 mile.

they told me, they start to pull back timing, and power at 70C
so 70C is the magic number i am aiming for.


yesterday, i was bleeding it by hand again the old school way. loostening the bleeder screws, bleeding the heat exchanger (mine is mercracing)
but it was making a mess, and its really hard to tell how much air is really in the system like this.

i took it for a quick pull, and from the bottom of 3rd gear to the top. i went from 30C to 66C.

still not good enough or even close.

so i spent all night thinking about how to do this the old school way. with a funnel or a tube of some sort.

for some reason this popped into my head
its a hair dye applicator bottle. they can be had for like $2
and can get them at any beauty supply store or walmart etc.

https://www.sallybeauty.com/hair/hair-color/hair-color-accessories/applicators/calibrated-applicator-bottle/SBS-305924.html?list=Home%7CSalon

https://imgur.com/a/9fG1vRJ


i just drilled the nozzle out a bit, and stuck it right in the heat exchanger, and well... the video will show you just how much air i had in there.
also there is no mess at all, and you can actually see when the bubbles stop.

another great thing. it fits right in the supercharger bleed holes. so you can pull the screws completely out.
cycle the pump, and watch and see the coolant and air come out. (this is a two man job though. that little bottle filled up fast. might be easier with a bigger bottle, and i will probably try it)
just make sure to shut the pump off, or you will have a mess.


https://youtu.be/fFeVmsh8UPg


but i had that bottle on the bleeder for the heatexchanger for about an hour. with the front end in the air. the amount of air i got out of the system is amazing.
i still might have a bit trapped in it, but i will check when i get another chance.

so i went for a drive to test it,and log. looking to see when i hit that magic number 70C

same thing as before. bottom of 3rd gear around 30C
i didnt hit 70C till the top of 4th. which is a huge difference from before.

i have not gotten a chance to get to the track, but i have a feeling my times,and trap will be much better.

I hope this helps anyone having trouble, or anyone who doesnt want to create a mess everywhere.That's terrible. You had to run the car that long to bleed most of the 6

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[MSq5]

It odd, it seems like anytime I hear about a HX not bleeding correctly its a Merc...

Simply a matter of odds, because so many of the newly installed ones come from Merc. A HX is a HX as far as filling and bleeding. Only differences are capacity, number of cores/passes, fitment, and price. Merc gets high marks in all areas.

If you can’t bleed completely, it’s not the HX brand. Bleed correctly. May take several attempts. Many are failing to turn their heater on high, fan low, to open the heater core. Bleed both supercharger bleed screws and the firewall heater core hose. If you think you still have air, use a coolant vacuum filler.

[stevemannn]

I'm not blaming Merc at all.
The HX is huge. It's the nature of the beast adding something that large and only having a tiny bleeder.

Vaccum bleeding doesn't work for everybody.
In theory it should,but it doesn't for everyone.

In theory, air should go to the highest point in the system, but if I were to have only bled the super charger, I still would have had a fuck ton of air in the system, cause it gets trapped in places.

This thread was just to help people out, and prevent a mess and a waste of coolant.

It can happen with any HX
Merc is just the one I purchased

[MSq5]

I'm not blaming Merc at all.
The HX is huge. It's the nature of the beast adding something that large and only having a tiny bleeder.

Vaccum bleeding doesn't work for everybody.
In theory it should,but it doesn't for everyone.

In theory, air should go to the highest point in the system, but if I were to have only bled the super charger, I still would have had a fuck ton of air in the system, cause it gets trapped in places.

This thread was just to help people out, and prevent a mess and a waste of coolant.

It can happen with any HX
Merc is just the one I purchased

Agree. The Merc does have its own bleeder valve. Your suggestion is worth a try and worth more than a try for those who still have high IATs on long pulls after repeated system bleeds or vacuum charges.

[NixonKB]

My Merc does have a bleeder valve - but I can't get it to do anything. Full open/closed - can't get air or water to come out of that thing.

If I vacuum the system every day for the next week, can I be confident there is no more air? I'm guessing only logging will tell me that...better try to figure that out today. Ive just read so many horror stories of the SC screws, I really don't want to touch them if I can avoid it!

Sorry for the thread hijack!

[stevemannn]

nothing came out of mine as well. which meant i had air in it. let the car run,and try my idea out.
now once i open the bleeder. coolant comes out right away.

you probably have to let the engine run as you do it. get it nice,and hot and pressurized.

[djn876]

Vacuum bleeding is not always 100% effective. There will potentially be high spots that need manual bleeding. You would likely just be repeating the same portions.

It's not that hard to bleed this system, unless that HX is problematic for some reason. Run the coolant pump with VCDS and bleed at the SC to help push some air through. Or build a rig to get the coolant higher than everything else and fill it slow with bleeders open until liquid comes out.

[NixonKB]

I've read that a manual impact driver with a #3 Phillips is the best bet to crack them loose...if they DO break off, are you leaking until you fix them, or do they still hold pressure?

I have the required tools - but don't want to risk it if it's gonna decommission my car until I find replacement screws!

[NixonKB]

Stevemannn- I took your advice on the Hx bleeder, except I used a big syringe (oil premix sucker) - and got a surprising amount of air out of that bleeder! You were 100% correct about the air, and the now it's flowing out while running. Thanks for the tip!

[stevemannn]

great to hear!

mine broke and they were leaking because the head twisted off. the manual impact driver works great, but the one broke after tightening. i reccomend getting backup bleeders before even messing with them

[blubaru]

My Merc is the older style and doesn’t have the bleeder :( is there anyway to add the bleeder after the fact? Currently trying to chase down high IAT and I’m just about ready to ditch this thing altogether.

[2by2handsofblue]

What is AIT and how do u know u have air in the system?

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[blubaru]

What is AIT and how do u know u have air in the system?

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I hit 93C on the dyno, according to P3 gauge. I’ve bled the system a few times so I’m thinking there must be an air pocket or something in the HX.

[stevemannn]

id imagine you could just tap the core it self, and install a bleeder.

[s4matty]

A good a way to top up the charger coolant if its divorced is grab a small funnel that fit in the 2 intercooler bleed screws holes and keep the resivior cap on then fill up directly into the intercoolers with bleed screws out.
Stick a rag around them to soak up and access while filling.Works very good topping up this way since there the highest point in the system
It can take awhile so be patient

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[theweebabyseamus]

Simply a matter of odds, because so many of the newly installed ones come from Merc. A HX is a HX as far as filling and bleeding. Only differences are capacity, number of cores/passes, fitment, and price. Merc gets high marks in all areas.

If you can’t bleed completely, it’s not the HX brand. Bleed correctly. May take several attempts. Many are failing to turn their heater on high, fan low, to open the heater core. Bleed both supercharger bleed screws and the firewall heater core hose. If you think you still have air, use a coolant vacuum filler.

I agree that many may not be bleeding correctly but the firewall/heater core shouldn’t affect the s/c loop as far as trapped air is concerned. I do wonder if being a quad pass is causing more air to be trapped.

[MSq5]

What is AIT and how do u know u have air in the system?

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I think OP or you may have meant IAT. If so, it is intake air temperature, sometimes referred to on other platforms as boost air temperature. It is the temperature of the air coming out of the supercharger and going into the intake manifolds of the engine. It is the final result of air being compressed (and greatly heated up) by the screws of the roots supercharger and the effect of the air-to-water saddle intercoolers trying to bring the temps back down.

Air in the cooling system causes IATs to rise because less coolant and water volume are available to transfer heat away from the engine and the supercharger core. Air in the system can cause IATs to rise. It can also cause hot spots in the engine block or cylinder heads.

[2by2handsofblue]

Thanks for the correction.

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[Jk79]

How do you run the pump with VCDS? I saw coolant pump under the option in the Engine module but it said it couldn’t be run.

[wes8398]

So figured this could help some people out.

i had crazy high AIT's even after vacuum bleeding,and trying to manually bleed the car by hand.
sent my logs to IE, and they were seeing up to 90C in a 1/4 mile.

they told me, they start to pull back timing, and power at 70C
so 70C is the magic number i am aiming for.

Curious... What were ambient temps when you were getting those numbers?

[MSq5]

I agree that many may not be bleeding correctly but the firewall/heater core shouldn’t affect the s/c loop as far as trapped air is concerned. I do wonder if being a quad pass is causing more air to be trapped.

I think you may be on to something about the quad pass core being more difficult To fill and bleed. I think I finally got all the air out. I had the cover off of the area over the HX and radiator for other reasons yesterday and opened the bleeder valve on MercRacing HX. Coolant freely flowed. So, I think it is completely full.

I think the key is to be patient. Had I to do over again, I would have completely unscrewed that valve and manually filled the HX before refilling the remainder of the system and bleeding through the s/c screws.

It takes patience. But, I like the quad pass design. The quality and fit are excellent, and price is the best out there, to my knowledge.

[Charles]

cycle the pump, and watch and see the coolant and air come out.

How did you cycle the pump? VCDS or another way?

[stevemannn]

ambient temps were around 40-50 F

my pump cycles when i turn the key on,but maybe its an IE DP thing, so i cant help you there.

[0mn1]

Posting this here too because it was a simple 10$ fix for s/c bleeder screws that snapped. Carefully extract plastic screws by torching a flat head into them and turning or like most of us drilling carefully and using picks to pull the remnants out.

M8 x 1.25 16mm screws and tap
Impact or hand tap

155322155323

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[GTSJeff]

Hey guys, I need some help. Totally the same story as the OP, except that when I turn the bleed screws (both sc and at hx, coolant flows out immediately. It flows out so fast I don’t even feel like I can unscrew the whole thing to place the bottle! Do you just keep unscrewing and have the coolant go everywhere while you get the bottle on? And do you do the heat exchanger or s/c screws first? Thanks! This is super frustrating. High IAT with dual pulley and newest merchx

[MSq5]

Hey guys, I need some help. Totally the same story as the OP, except that when I turn the bleed screws (both sc and at hx, coolant flows out immediately. It flows out so fast I don’t even feel like I can unscrew the whole thing to place the bottle! Do you just keep unscrewing and have the coolant go everywhere while you get the bottle on? And do you do the heat exchanger or s/c screws first? Thanks! This is super frustrating. High IAT with dual pulley and newest merchx

Bottle? Never used a bottle on the HX valve, the s/c bleeders or up at the heater core.

Do not unscrew the bleed screws. Just crack them open and close when pure coolant with no bubbles comes out.

I just wrap paper towels around the bleeders to absorb the overflow.

[GTSJeff]

Am I opening them too wide if it spraying a boiling hot stream straight out all over the place including myself?


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[TheGreatDecay]

Am I opening them too wide if it spraying a boiling hot stream straight out all over the place including myself?


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Lol yeah man. They only need to be opened a tiny amount to be bled enough, like 1 1/4 or 1/2 turn

[MSq5]

Am I opening them too wide if it spraying a boiling hot stream straight out all over the place including myself?


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Fixed my post. Just crack them open.

Bleed one at a time.

Start at the lowest point, the heat exchanger. You can open that valve all the way. It can be hard to bleed. Once it is clear fluid, no bubbles, close it.

Then crack only one s/c and bleed until clear. Close it.

Keep topping off your coolant reservoir. It helps to have a helper raising engine rpm to 2,000.

Then, do the other s/c the same way.

Finally, the heater core. Only do it last. Its under the panel between the firewall and windshield. Remove that panel to access it.

You have to unclamp the left hose and pull it out to expose the hole in the bleeder hose. Looks like this:

https://i.postimg.cc/xCq9hKJ3/915-C7-C4-D-818-E-4-F35-A39-F-E83-DC19-C332-A.jpg

[GTSJeff]

Ok, a local AZ member came over yesterday and helped me go through it all. We ended up doing the bottle/gravity method even though it made a huge mess as well as conventional method. Not sure how the OP didn’t have the fluid just overflowing the bottle. TONS of air coming out.

After a whole afternoon we got it to 70° at the top of third gear. This is on a 187/57 dual pulley with newest MercHX and 55:45 coolant to water ratio because driven in cold weather. think I need to keep going?


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[GTSJeff]

Thanks for the tips to just crack the screws! It was also tripping me up to watch for the tiny bubbles or uneven stream. Ended up using a 4L jug of premixed G13.


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