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MZ777 05-08-2015 09:55 AM

Mishimoto radiator myth + OEM fan/shroud
Has anyone on this board besides @Red Raspberry installed an aftermarket radiator with an aftermarket IC and kept the stock fan? If you are one of "us", please show your kindness and report your coolant temps if you would...

I am having a strange issue and I would appreciate if someone could point me in the right direction...

It's been a week since I installed my Treadstone FMIC along with the Mishimoto 2.0 radiator and I now deal with higher coolant temperatures than before. I don't remember seeing the coolant temps go above 200F with my stock radiator although not that I've been checking every time I drove... I troubleshot every thing possible and I am pretty certain that I do not have any air in the system nor do I have any leaks. I've used 50/50 premixed PEAK brand coolant/antifreeze and I do live in warmer/humid climate. I also don't know the factory mixture on coolant, but figured 50/50 would do it.

I don't want to make this post long and boring, but I feel like it is important to tell everything possible in order to investigate and perhaps find a solution.

1) First thing's first - I had to chop the lower part of the shroud due to the IC not fitting properly at all:

2) After fighting for a while, it looks like this installed:

- And I drove with that big ass hole for one week because I didn't think it would affect the coolant temperature due to better airflow underneath; plus, the size of the radiator itself would compensate. These are my temps driving like this:

Going to work -

Coming back home the same day -

From reading here and there, I realize the hole needed to be plugged in because the shroud doesn't operate properly at directing the air... So, yesterday I did this:


Made this:


Temps going to work after this block off plate:

I will post the tems when I go home later today...

What would the dual fan kit do for me? I think nothing... Just as stock, it would be coming on at 200F and turning off 190-195F? Well, this is how it is now, and there's no point in getting the slim fans in this case unless the turn on values can be modified in the tune and since PRW doesn't offer this and won't modify anything - I see no benefit getting the slim shroud kit from @[email protected]

This radiator upgrade didn't really do anything for me. $260 later -- it is a worthless upgrade after all. I am not the guy who just buys all the available parts on the market but I feel like the OEM fan is not working efficiently with the aftermarket radiator.

Topics looked at:


Red Raspberry 05-08-2015 10:04 AM

Perhaps air is bypassing or not getting to the radiator from the front due to gaps?

It was not all that hard to put in a stand alone temperature controller for the fan.

MZ777 05-08-2015 10:30 AM

There's plenty of opening for the air to pass through the grille to reach the radiator. The bottom of the shroud is sealed now but I am yet to see any significant difference.

From reading the mentioned threads, the ECU doesn't turn on the LOW fan speed until the temperature actually reaches 200F? Isn't this a little too high?

Again, I don't want to throw money on UNIQ's slim fan shroud UNLESS I have to, because for some reason I doubt it would actually lower the temps at all since they won't even come on until the coolant is at 200F... How come the temps were a lot lower with stock IC/rad? This makes no sense to me.

I guess my thing is: after spending close to $300 on this radiator and after all I had to go through JUST to install it, I am now afraid to spend more money on something that I don't even know whether if it will actually help or not...

Red Raspberry 05-08-2015 10:41 AM

200F is the norm but it appears that there is not enough air going through the radiator. My low speed fan is disabled as BR tunes have it running all the time (stupid) but is unavoidable from what I am told.

I did not mean not enough air going into the grill but air slipping off to the sides once through the condenser. There are some side shields that normally are on the sides between the radiator and condenser.

MZ777 05-08-2015 11:07 AM

If you're talking about the foam strips, then there are there, on left and right but not on top or bottom.

Red Raspberry 05-08-2015 11:09 AM

Parts 29136 and 29135C they are hard plastic.

MZ777 05-08-2015 11:20 AM

No, those had to come off because the treadstone core wouldn't clear them...

Red Raspberry 05-08-2015 11:22 AM


Originally Posted by MZ777 (Post 3613634)
No, those had to come off because the treadstone core wouldn't clear them...

So is there a big gap on the sides where they were?

MZ777 05-08-2015 11:33 AM

Not really, there is almost no gap. Besides, I upgraded to a real power steering cooler too because the stock line would not allow the core to be flush. So, the line is gone, the power steering cooler is behind the core mounted on the radiator support (right below the radiator) and the core fitment is just perfect.

MZ777 05-08-2015 07:55 PM

Ok so driving home today it still went up to 215 for a little bit went back to 195 range

MZ777 05-08-2015 08:01 PM

I also noticed that the temps tend to stay pretty steady when AC is on. The only thing I can conclude from this is that the temps are in ok'ish range when the fan is on high speed.

Again, I don't know if getting the slim fan setup will be beneficial, so I think I may hold off on getting the shroud from uniq for now unless if they will send me one to test LOL

MZ777 05-09-2015 07:11 AM

Going through the thread to make sure I didn't miss anything and Red, those plastic shields you've mentioned are not between the condenser and rad, on mine there were on the very front, right behind the bumper. I've never had anything between the rad and condenser.

Red Raspberry 05-09-2015 08:42 AM

The factory fan or any fan will not do any good unless you can get it to turn on sooner. I still think there is not enough air going through the radiator naturally.

MZ777 05-09-2015 09:38 AM

Uniq claims that their shroud will make my temps cooler. I will try sending a message to prw and see if Bill is willing to modify the fan settings in the tune. I doubt that he is going to but everyone local tells me to ask the tuner to do so. That will keep me away from installing the external fan controller... I want the car to do everything, otherwise i feel like I'm back to my 240 days when i had to flip the switch every time i drove. Bleh.

Red Raspberry 05-09-2015 09:47 AM

The shroud on the back will not help unless the fans are on.

FWIW adding a simple ground wire to the relay coil ground and a switch is easy to do and it does not affect the way the ECU controls the relay.

MZ777 05-09-2015 10:35 AM

That's what I'm saying - based on what @[email protected] and @Snoopy0812 are saying about their product - even with one fan on there will be more cooling compared to the OEM one. Personally for me - it is hard to believe...

I also sent a message to Bill at PRW and asked if he would be willing to modify the fan settings for me. Let's see what he says.

Red Raspberry 05-09-2015 10:46 AM

If the radiator is good and has good air flow you do not need the fan when moving. My fan only comes on with the AC unless I idle for 10-15 minutes to get the coolant temp up to 200F.. The OEM lo speed fan will not come on at speeds over 35 mph unless the temperature exceeds something like 215F. The OEM fan is quite good if the radiator does it's job. I do not believe the fan is your problem.

You can unplug the connector on the back of the shroud, pass side. Jumper that connector with some 12 ga wire. This will run the fan at hi speed instead of lo speed. It will not affect the hi speed fan logic at all.

MZ777 05-09-2015 11:06 AM

Air flow is what I was going for when I left the bottom portion of the shroud open but it is now sealed and so far I have not noticed any difference. Yes, I am aware of that resistor 'mod' but i have not tried it yet.

Also, I received a message from Bill @ PRW and just as I expected, he is not going to make the changes I inquired about and I respect that. Here's his message:


If you are adding things that were not tested such as a radiator then you have defeated the purpose of getting a canned tune and should be looking to purchase a Haltech so you have full control over your car.

So you are aware my car makes 603whp and is still using a factory radiator so i know it's more than capable..

You may want to make sure you filled your coolant system 100% and that you have zero air bubbles (which is 90% likely your case for higher temps as air gets trapped and causes excess heat to hit the CTS (coolant temp sensor)).

MZ777 05-09-2015 11:14 AM

And another message that made me feel a little better:


I have customers in Las Vegas running 18G & 20G turbos using my stage 2 tune as a base and running a CMD to control fuel and boost who have the same fan settings as what you have and their summer temps reach 115+ and they haven't had any issues, they are also running bigger radiators so i'm sure you will be just fine.

One thing to keep in mind is a bigger radiator is going to cool the coolant faster which means cycling the coolant through the engine at a much faster rate instead of requiring the fan to always be on to try and cool sitting/waiting coolant in a small factory radiator before cycling coolant back to the engine.

I've tested my stage 1 and 2 tune in the desert of Arizona at temps of 106+ with a customer who had full bolt ons so i feel confident that the tune is fine.

Red Raspberry 05-09-2015 11:23 AM


Originally Posted by MZ777 (Post 3615241)
Air flow is what I was going for when I left the bottom portion of the shroud open but it is now sealed and so far I have not noticed any difference. Yes, I am aware of that resistor 'mod' but i have not tried it yet.

Also, I received a message from Bill @ PRW and just as I expected, he is not going to make the changes I inquired about and I respect that. Here's his message:

Sealing off the bottom of the shroud on the 2L will make the fan more efficient. What I meant when saying more air flow is natural from the front of the car through the radiator. The ideal way and what my car does is not to need the fan unless under extreme conditions. I can tell you that the OEM radiator will not cool the car on a road course in hot temps. Driving around town or doing a few dyno pulls are not a true test of the cooling system. Try driving flat out for 15 minutes at high rpms and +90F temps. Mine was be in the 250F range with the OEM equipment.

And unless someone is using Torque or other data reader they have no idea what the coolant temp is because the factory gauge is such a joke.

Back to the air in the system this is what I said will be true without a good overflow system. The Gen Coupe is very hard to keep air out and any opening of the radiator will lose the prime on the coolant over flow hose and take many heat/cool cycles to purge the air and keep the hose full.. You should replace that with clear hose. If the system is good then there will always be coolant in the hose up to the radiator. If there is air in this hose then there is air in your pressurized cooling system.

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