2G Folks with big FMIC and/or cooling issues, how did you deal with keeping temps down? [2G GSX]

[Will Kellermann]

Hi everyone,

The weather here in Idaho is beginning to warm up and with that, the temperatures of my coolant are rising as well. I've have some anxiety about my temps the last few years as I've had it overheat quite a few times when I was able to drive it. It has been in and out of phases of being broken down for various reasons. It's the worst at idle while at stoplights, it can rise during driving, and it will really rise in temp during pulls (to be expected). For context, these are the parts on my 2G GSX relevant to cooling:

• OEM Radiator Cap
• OEM Thermostat
• OEM Radiator fans
• Punishment Racing FMIC
• Megan Racing Aluminum Radiator
• 16G turbo
• China-special Exhaust Manifold wrapped in titanium heat wrapping
• Polyurethane 2Gb front bumper, with the mustache on the front opening (stock bumpers don't have this, only the aftermarket ones)
• Custom fan override turn-on switch (so I can manually turn on the fans if need be)
• AC condenser, compressor, and refrigerant lines deleted

So from the list above, the things I did to try to mitigate overheating was the fan override switch, upgraded radiator, AC condenser delete, wrapping the exhaust manifold. I'm fairly certain that the FMIC is the cause of the issues because it takes up all of the real estate of the opening in the front bumper, starving the radiator for cool air and wasn't an issue before it to my best recollection. I just purchased a bottle of Royal Purple Ice to throw into my coolant to reduce temps 3-5°F, and I know it's just a band-aid, not a solution.

I've read a ton of threads on here and tried a few of the fixes, which I think have helped but really the answers can be all over the place. So far, the next options I'm aware of are upgrading fans, different radiators, different intercoolers, ducting between the radiator and intercooler, different radiator caps, different thermostats, different coolant mixes. Stuff like that. Also, if anyone is wondering, yes, I've burped the coolant system of air bubbles. I've been pretty thorough in making sure it's topped off and putting in coolant correctly.

I'd prefer to invest in the solution that is one or a few parts that will solve my problem in it's entirety. I'm willing to spend some money, just want to get it done. I'm not looking for the solution on a silver platter, but trying to gather a litmus of what people have done to solve temperature issues with a big FMIC. I apologize in advance for the lengthy write-up, I wanted to provide the best context I can. Disclaimer: I want to keep a big FMIC and cutting nostrils/2 big holes on the top section of the front bumper for more air is not an option.

To narrow in, what was the cause of your overheating problem, the FMIC or were there several? What actually solved your overheating issue?

Anything helps!
-Will

 

[99dsmer4g63]

Well I know this isn’t what you want to hear but I have a big front mount and have absolutely no overheating issues at all. Never had. I only run one slim electric fan too. No heat wrap on the tubular manifold. On 90+ degree days in PA idling in my driveway the hottest I’ve seen is about 210 or so and the fan kicks on and maintains it pretty well.

I run a 185 thermostat and have no ducting or anything. I do a have an aluminum radiator but didn’t have issues with the stock one either. I run just an off the shelf green coolant concentrate that I mix with distilled water to a 50/50 mixture.

Cruising down the road I stay at a consistent 180-185. Ecm link shows 190 maybe after a hard pull. Even on the dyno with a fan in front of the car it never seen over 195.

I think you have some other issue that you are trying to mask instead of solve. Sorry I wish I could help you but that’s my .02 take it as you want.

Good luck, Daniel

 

[dsmtun3r98gst]

Well I know this isn’t what you want to hear but I have a big front mount and have absolutely no overheating issues at all. Never had. I only run one slim electric fan too. No heat wrap on the tubular manifold. On 90+ degree days in PA idling in my driveway the hottest I’ve seen is about 210 or so and the fan kicks on and maintains it pretty well.

I run a 185 thermostat and have no ducting or anything. I do a have an aluminum radiator but didn’t have issues with the stock one either. I run just an off the shelf green coolant concentrate that I mix with distilled water to a 50/50 mixture.

Cruising down the road I stay at a consistent 180-185. Ecm link shows 190 maybe after a hard pull. Even on the dyno with a fan in front of the car it never seen over 195.

I think you have some other issue that you are trying to mask instead of solve. Sorry I wish I could help you but that’s my .02 take it as you want.

Good luck, Daniel

With you on this one as well. When it gets to 90+ down here not once did I have an overheating issue, that is with a VRSF FMIC, mind you I cut out the black upper portion of my front bumper as well as trimming the same amount off the crash support bar. All of my cooling system is also stock.

Hopefully this is not the case for you but is there any slight chance that there may have been some neglect in the cooling system? like not using proper antifreeze/coolant which could cause internal rust issues thus blocking/narrowing cooling passages?

 

[99dsmer4g63]

Guess I should add for disclosure that I did cut out the black grill looking part of my bumper as well. I didn’t even remember I did that till I seen the post above mention it. I did this though because I liked the look of it and had nothing to do with cooling. I also don’t even have a crash bar because the front mount is so damn big .

-Daniel

 

[1999RSfwd]

I have a Mishimoto M-Line intercooler without a crash bar because of the intercooler, and I haven't cut that black part of my front bumper... yet. I also have all my ac stuff.
I run a KOYORAD Hyper-V 36mm Radiator with one radiator fan.
My GSX has never over heated on me, and I drive it plenty during the summer, and in stop and go traffic.

 

[1990TSIAWDTALON]

Put a lower air foil under the radiator support to scoop up air going under the car and funnel it into the radiator. Helped my car tons. I have a 1g tho.

 

[DSMPT]

At least you should make the fan dual with the factory fans or better ones (always turn on 2 fans in the same time) and use a higher pressure radiator cap.
Those were my solutions (as I own a 2g with a FMIC and live in one of the hottest place in the world), make the factory fans dual function and use a higher pressure cap. So far those stopped the high temp issue on my 2g. With a 0.9kg/cm stock pressure cap or a 1.1kg/cm cap, I had the high temp issue much more often in many situations (the familiar issue with 2g people with a FMIC and without duct that the temp gauge stays at 3/4 position but not overheating), I ended up using a 1.3kg/cm cap. In my case with a 1.3 cap, even after pull the car that makes the EGT reaches 900-950 degree C, the coolant temp seems to be fine.
I own 1g and 2g, 2g is much more difficult to keep the temp cool than 1g due to very tight layout under the hood.

 

[chrysler kid]

Here are my thoughts

Dual core radiators are thermally inefficient and cause reduced air flow through the radiator itself. The radiator itself becomes heat soaked and the fans are not able to get enough air flow through it due to air restriction and turbulence, and no fans will keep up. Also I consider the aluminum end tanks really get hot and actually make under hood temps higher in the engine bay compared to a factory radiator. I have burned my hand so many times reaching to un latch the hood on an aluminum radiator. Most of the time the factory resevoir cant be used and the shitty ebay ones have a leak and now you have that issue of the car getting too hot one day when its low on coolant and hot spots the cylinder head and warps it

Seeing how this seems to be hit or miss, some people say no problems with a dual core, while a majority of others with dual cores have complaints

This could also be because the aluminum radiators were put in because of another issue with the cooling system. Ive removed hoods on 2g's before to prove a point, and they would still over heat just sitting there. On this particular case the cylinder head was warped and the car was leaking coolant into the combustion chamber, just not enough to smoke out the tailpipe. The aluminum radiators do not actually cool any better, and were only added because the car already had cooling system issues

So to conclude, if the car is getting hot sitting in the driveway with the hood open or closed, more likely the car had an overheat condition in the past that was not caught quick enough that has damaged the head gasket, or warped the cylinder head

So to satisfy my next gut punch, perform a hot compression test, you will probably notice one cylinder that is much below the others. Typically for whatever reason cylinder 3 is usually unhappy

Still reading? Ive had 2 different second gens with big front mounts and ac here in texas, with stock fans and new factory style radiators, with stock hoods, and never had over heating problems. I think my main complaint was the AC wasnt as cold when it was just idling at a stop light

 

[chrysler kid]

Also we've alread had 90 degree temps here in texas this year, if you are overheating after a pull and its 72 degrees outside, there is something drastically wrong with your cooling system. My hypothesis being a warped cylinder head or head gasket

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[FIBA M - EC17PSE]

You have quite a thin intercooler so its telling me you need to do some duct work then. Dual fans will work well for you.
If you cover any gaps before and inbetween the cooler and rad yoir airflow will be massively improved and all go through the rad and help alot! As soon as it bypasses the rad your cooling is massively effected.

Some get away without this but its not often or its luck.
Thankfully your bumper is still recessed so you have a nice opening to trap air through it. So duct the gaps and you will get it solved ok.

 

[Will Kellermann]

Well I know this isn’t what you want to hear but I have a big front mount and have absolutely no overheating issues at all. Never had. I only run one slim electric fan too. No heat wrap on the tubular manifold. On 90+ degree days in PA idling in my driveway the hottest I’ve seen is about 210 or so and the fan kicks on and maintains it pretty well.

I run a 185 thermostat and have no ducting or anything. I do a have an aluminum radiator but didn’t have issues with the stock one either. I run just an off the shelf green coolant concentrate that I mix with distilled water to a 50/50 mixture.

Cruising down the road I stay at a consistent 180-185. Ecm link shows 190 maybe after a hard pull. Even on the dyno with a fan in front of the car it never seen over 195.

I think you have some other issue that you are trying to mask instead of solve. Sorry I wish I could help you but that’s my .02 take it as you want.

Good luck, Daniel

Ok, good to know not everyone is having this issue. Something else must be the case. I used Valvoline Zerex Asian Vehicle coolant in my radiator. Is that stuff okay? Also, I've only done mild tuning to the vehicle but it still has some work needed in that department. Could the tune affect temps that drastically?

 

[Will Kellermann]

With you on this one as well. When it gets to 90+ down here not once did I have an overheating issue, that is with a VRSF FMIC, mind you I cut out the black upper portion of my front bumper as well as trimming the same amount off the crash support bar. All of my cooling system is also stock.

Hopefully this is not the case for you but is there any slight chance that there may have been some neglect in the cooling system? like not using proper antifreeze/coolant which could cause internal rust issues thus blocking/narrowing cooling passages?

I'm definitely planning on cutting off the black part on the top of that bumper. I used Valvoline Zerex Asian Vehicle coolant in my system, if that is ok. When I replaced the thermostat, I didn't see any rust on that part of the system. It also has a new Gates Water Pump that's been on there for about 4000 miles and didn't see any rust there either. Is there a different area I should inspect that tends to accumulate rust? Also, do you think the VRSF has better passage for air to the radiator, seems like quite a few people run the punishment china-special FMIC ok, but some have reported airflow issues with it.

 

[Will Kellermann]

Guess I should add for disclosure that I did cut out the black grill looking part of my bumper as well. I didn’t even remember I did that till I seen the post above mention it. I did this though because I liked the look of it and had nothing to do with cooling. I also don’t even have a crash bar because the front mount is so damn big .

-Daniel

Yeah I don't have the crash bar either, so I am going to cut that black part off.

 

[Will Kellermann]

I have a Mishimoto M-Line intercooler without a crash bar because of the intercooler, and I haven't cut that black part of my front bumper... yet. I also have all my ac stuff.
I run a KOYORAD Hyper-V 36mm Radiator with one radiator fan.
My GSX has never over heated on me, and I drive it plenty during the summer, and in stop and go traffic.

Hmm, interesting. I may consider doing a new radiator. From the fact that a lot of you guys are saying there isn't anything wrong with running the FMIC temp-wise, I'm beginning to believe there is something else going on.

 

[Will Kellermann]

Put a lower air foil under the radiator support to scoop up air going under the car and funnel it into the radiator. Helped my car tons. I have a 1g tho.

This sounds like something that isn't too expensive to do and a good addition in general for getting air to the rad. Is there one fitted for DSM's that I can buy or did you have to custom fab?

 

[Will Kellermann]

At least you should make the fan dual with the factory fans or better ones (always turn on 2 fans in the same time) and use a higher pressure radiator cap.
Those were my solutions (as I own a 2g with a FMIC and live in one of the hottest place in the world), make the factory fans dual function and use a higher pressure cap. So far those stopped the high temp issue on my 2g. With a 0.9kg/cm stock pressure cap or a 1.1kg/cm cap, I had the high temp issue much more often in many situations (the familiar issue with 2g people with a FMIC and without duct that the temp gauge stays at 3/4 position but not overheating), I ended up using a 1.3kg/cm cap. In my case with a 1.3 cap, even after pull the car that makes the EGT reaches 900-950 degree C, the coolant temp seems to be fine.
I own 1g and 2g, 2g is much more difficult to keep the temp cool than 1g due to very tight layout under the hood.

I have the fan override which turns on both fans at the same time. You eluded to how your temp gauge would go to 3/4 but not quite overheat. Now that you mention it, I have this happen to me a lot! I'm gonna make a 1.3 cap one of my next additions. Thanks

 

[Will Kellermann]

Here are my thoughts

Dual core radiators are thermally inefficient and cause reduced air flow through the radiator itself. The radiator itself becomes heat soaked and the fans are not able to get enough air flow through it due to air restriction and turbulence, and no fans will keep up. Also I consider the aluminum end tanks really get hot and actually make under hood temps higher in the engine bay compared to a factory radiator. I have burned my hand so many times reaching to un latch the hood on an aluminum radiator. Most of the time the factory resevoir cant be used and the shitty ebay ones have a leak and now you have that issue of the car getting too hot one day when its low on coolant and hot spots the cylinder head and warps it

Seeing how this seems to be hit or miss, some people say no problems with a dual core, while a majority of others with dual cores have complaints

This could also be because the aluminum radiators were put in because of another issue with the cooling system. Ive removed hoods on 2g's before to prove a point, and they would still over heat just sitting there. On this particular case the cylinder head was warped and the car was leaking coolant into the combustion chamber, just not enough to smoke out the tailpipe. The aluminum radiators do not actually cool any better, and were only added because the car already had cooling system issues

So to conclude, if the car is getting hot sitting in the driveway with the hood open or closed, more likely the car had an overheat condition in the past that was not caught quick enough that has damaged the head gasket, or warped the cylinder head

So to satisfy my next gut punch, perform a hot compression test, you will probably notice one cylinder that is much below the others. Typically for whatever reason cylinder 3 is usually unhappy

Still reading? Ive had 2 different second gens with big front mounts and ac here in texas, with stock fans and new factory style radiators, with stock hoods, and never had over heating problems. I think my main complaint was the AC wasnt as cold when it was just idling at a stop light

Haha, still here, you talk like a grizzled DSM veteran, it's funny, but really helpful. Yes, it did overheat in the past. What happened was the stock radiator cracked where the top opening connects to the upper radiator tube. I replaced it with the Megan Racing aluminum rad, thinking it was an upgrade. I guess I was wrong.

I have the equipment to do a hot compression test, so I'll go ahead and give that a try to see if it warped my cylinder head at all. And also, yes the stock reservoir tends to get low after a few weeks, so it must be a slow loss of coolant. Thanks for your feedback

 

[Will Kellermann]

Also we've alread had 90 degree temps here in texas this year, if you are overheating after a pull and its 72 degrees outside, there is something drastically wrong with your cooling system. My hypothesis being a warped cylinder head or head gasket

Ok, someone else said the same thing. I'm going to be doing a test here shortly to see if this is the issue.

 

[Will Kellermann]

You have quite a thin intercooler so its telling me you need to do some duct work then. Dual fans will work well for you.
If you cover any gaps before and inbetween the cooler and rad yoir airflow will be massively improved and all go through the rad and help alot! As soon as it bypasses the rad your cooling is massively effected.

Some get away without this but its not often or its luck.
Thankfully your bumper is still recessed so you have a nice opening to trap air through it. So duct the gaps and you will get it solved ok.

Yeah this was something I wanted to try eventually. Have any recommendations for what I use to create the ducting?

 

[FIBA M - EC17PSE]

Yeah this was something I wanted to try eventually. Have any recommendations for what I use to create the ducting?

anything from foam if its possible to plastic or thin sheet aluminum, finding a way to glue it on can be tricky with heat but people here have done it many times so can search ducting here and it can be stuck up or bolt/rivnut in certain locations

 

[Will Kellermann]

anything from foam if its possible to plastic or thin sheet aluminum, finding a way to glue it on can be tricky with heat but people here have done it many times so can search ducting here and it can be stuck up or bolt/rivnut in certain locations

Got it, really appreciate your input.

 

[Mello]

First thing I'd do, since this is a cooling issue, is a coolant pressure test & make sure thete's no leaks, like small pin hole leaks that won't drip but vent steam so you can't hold pressure. If you find nothing then next up would be a leakdown/compressions test. Also, i run a FMIC on my 2GB without any cooling issues & haven't needed to do any special ducting cutting, bumper hole drilling.

 

[Will Kellermann]

First thing I'd do, since this is a cooling issue, is a coolant pressure test & make sure thete's no leaks, like small pin hole leaks that won't drip but vent steam so you can't hold pressure. If you find nothing then next up would be a leakdown/compressions test. Also, i run a FMIC on my 2GB without any cooling issues & haven't needed to do any special ducting cutting, bumper hole drilling.

Yeah, from other people responding saying they're not experiencing issues, it leads me to believe what you just said, at least one of the two things being coolant leak or a warped head are the issue. So I'll be investigating that first, thanks for your input.

 

[99dsmer4g63]

Ok, good to know not everyone is having this issue. Something else must be the case. I used Valvoline Zerex Asian Vehicle coolant in my radiator. Is that stuff okay? Also, I've only done mild tuning to the vehicle but it still has some work needed in that department. Could the tune affect temps that drastically?

Yeah if your car is running really lean it will definitely make it run hotter. I’m no tuner by any means but from experience a lean idle or cruise mixture seems to raise the temps.

-Daniel

 

[TerminalTalon]

There’s something else going on.