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Cooling System Troubleshooting

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Anthony Yacullo

Proven Member
148
3
Aug 20, 2014
Reseda, California
Hey all,
I have had this dsm for about a year now and even on the t25 had some cooling issues during the hot vegas summer. Now I am on the a 16g with a heat blanket on my manifold and coated o2 housing. Running a mixture of 70% distilled water and 30% antifreeze, I still get hot temperatures in Southern California.

Temperatures in 65 degree ambient range from 190-196 on highway and up hill 200.
Temperatures in 80 degree ambient range from 193-203 boosting.

Although these aren't bad temperatures it will get hotter and last weekend I drove to vegas 95 degrees outside and I got up to 213-220 with and without ac on.

Based on other posts I have done the following;
I replaced my radiator cap, verified head gasket is good, 99.9% sure my t-stat is working (180 degree), flushed radiator, checked airflow by putting a piece of paper on my FMIC with fans on.

My cooling system is stock, stock fans, rubber hoses, stock radiator (108k miles).
I plan to keep my ac, and I have noticed that my fins of both radiator and condenser are a little bent.


Anyways I am open to suggestions and I am leaning towards taking radiator out and blowing it with air compressor and or replacing it with better radiator. Possibly thinking about opening my hood to vent more as my last 2g had it and seemed to help.


Thanks,
Anthony
 
One of the first things I do with DSMs is replace the stock radiator. I had the neck crack one time going up a hill and it was a nightmare. Although it looked OK, the neck was completely discolered under the hose and very brittle. I'm not saying this is your problem, but I wouldn't gamble especially when it gets really hot out.
I've had a $100 CX racing aluminum dual core rad on one of my DSMs for two years with no problems, plus it has a greater capacity than the stock rad. That car always ran a little hot when I got her, and stopped when I replaced the rad. Of course, you could pay much more, or get an even larger capacity rad, either way I recommend it.
 
I can say that logging in Link on my brothers' DSM here in the south, the temps will raise and dip somewhere between the lines of 215-220. That being said, we'll address this like it's a troubleshooting process.

1 : Ensure the system is burped. Now it's pretty commonly shared that our systems burp themselves, but there is quite an easy way to speed it up. This involves you getting a large funnel with a nozzle that will wedge (gently) into the fill point above the thermostat housing. Start the car, turn your heat one, ensure the funnel is sealed as best as you can against the inside of the fill hole, and pour your coolant/water until it fills up about half way. This standing fluid in the funnel is now the absolute highest point in your cooling system and from here we play with gravity. Have a buddy help you squeeze your radiator hoses. 9/10 times you'll see large air bubble burp up through the funnel which is cause the coolant level to drop. Do this until the car is up to temperature and the thermostat opens/cycles. Continue until the vehicle stops accepting coolant. This is something I learned from an old timer to "get those pesky air pockets outta the damn water pump in those damn ole' chevy's." Since then I've resolved simple temperature fluctuation issues with this method.

2 : Look into better cooling solutions. Aluminum radiators are a good investment. Personally I like to coat the top of them so I don't scald my skin off when I forget how hot they get and I'm leaning into the engine bay. Look into higher flow fans and setup in a push-pull pattern if you have the room. Better air flow plus better heat dissipating materials will drop your temps significantly.

3 : Ensure your antifreeze/water mixture is correct. Remember : Antifreeze's purpose isn't to cool the engine. It's to lubricate, raise the boiling point, and lower the freezing point of water. The water in the system is what actually does the best of the job with transferring heat from the engine to the radiator. Too much antifreeze in the summer and you'll simply see overheating issues. Too little antifreeze and the water in the system will boil, thus creating an overheating issue. It's a fine balance in the two depending on the environment you live in. The "safe zone" is 50/50, but 60/40, 70/30, and so on can be used depending on what's needed.

4 : Clean. Clean everything. Clean your radiator. Clean your intercooler if it sits in the pathway of your radiator assuming you have one. Ensure your fans are actually kicking on and free them of any debris. Make sure no blades are cracked, deformed, rotted, etc. Make sure there's nothing pulling the shroad away from the radiator and if you have slim fans ensure they are butted up against the radiator as best as they can be.
 
Oh, that reminds me : Check your thermostat. Make sure it's functioning well and not sticking. Perhaps even drop 5*ish if need be so it doesn't hold the "cool" coolant in the radiator quite as long and cycles a tad bit sooner. Don't do a drastic drop by, say, 30* or something.

Hope you get it resolved!
 
Try running it without the thermostat, living out west I wouldnt bother to run one, especially in the summer and of course some of the guessers out there will tell you that you will run cooler with one but try it once and see.
 
I'm in Texas and I used to have a really bad cooling problem. I replaced all my hoses, got a Mishimoto radiator and hoses, I'm using a stant 180* thermostat and burped the coolant with pre 50/50 and my car runs fine, even when I'm doing runs at high rpm. I'm on an E3-16g with an FP manifold and stock o2 housing. No blanket or air vents and everything still runs fine
 
Oh, that reminds me : Check your thermostat. Make sure it's functioning well and not sticking. Perhaps even drop 5*ish if need be so it doesn't hold the "cool" coolant in the radiator quite as long and cycles a tad bit sooner. Don't do a drastic drop by, say, 30* or something.

Hope you get it resolved!
I am a little confused by lowering my tstat temperature. Wouldn't that cause the coolant to heat faster?
 
Thermostat sets the minimum temperature. It blocks coolant flow, disabling your cooling system from operating, until it heats up and lets coolant flow to cool the engine. Without one, your engine would take much longer time to heat up, but rest assured, it will still heat up, especially if you are considering removing the t-stat to try to reduce operating temperature. It has nothing to do with keeping temps below some desired maximum. That's what the rest of the cooling system does. Some people put in a lower thermostat as a temporary fix or think lowering the minimum temp will magically also lower the max temp.

Disclaimer: Some t-stats are old and open too little, get stuck etc... So yes, putting in a properly working t-stat will fix a problem caused by one that does not work.

XiKieyaZl has the right idea. A slightly lower t-stat. Not a "JDM yo -50 degree lower" t-stat.

Some side effects of running your engine at a lower temp than it was designed for...
--Excessive emissions
--Lower gas mileage
--Increased engine wear (colder engine=larger gaps...)
 
The fmic combined with the condenser I would say is the issue. I am dealing with that right now. I drive the car with both fans always on, the coolant mixture is fine, I have a fluidyne radiator and two Spal fans one to push one to pull. Not to mention that my heater is on full blast constantly which is a pain in the ass. I literally feel drained and tired after driving my car due to the heat seriously. The temps do stay on average 180 to 190 degrees when cruising. It will creep up at a standstill can reach 215 degrees. Once moving the temperature according to link and my digital autometer gauge will quickly come back down to that happy range of 183 to 192 degrees.
I finally ordered a hood scoop from road raceenginnering's sister company http://roadracemotorsports.com/stor...index&manufacturers_id=5&sort=2a&filter_id=81

I went with the 18x10 in fiberglass one 99.00. They have the 200.00 carbon fiber version of the same scoop.

I will place it as others have over the manifold and radiator area on the hood.
I have also ordered two 350z intake vents(similar to STM vents)to go into my front bumper.

http://www.dsmtuners.com/threads/front-bumper-cut-outs-cooling.427844/#post-152887024

I'm almost 99.9% sure this will correct my cooling issues. I too want to keep my a/c.
To really eliminate my cooling issue I would have to get rid,of my condenser but that's not happening. Need my a/c.

I'm not gonna bother with the ducting stuff because when I had a smaller spearco FMIC and different exh mani turbo setup temperatures were normal with a/c running. I will put some weather stripping between the radiator support and the radiator though. Maybe some racing tape to block the holes by the hood latch area where I can look down and see my fmic.
My ETS ultra short race fmic is twice the size of my old spearco ,4 inches thick to be exact. Very efficient as I log nice low,IATs in the link.

I will keep all posted after I install the hood scoop and vents.
 
Last edited:
If your cooling system works fine at highway speeds, and not fine during stop/go, you probably have a fan issue. Working effectively at highway speeds and sustained RPM engine heat production suggests it is capable of removing heat. I had the opposite problems, and deduced my fans were good, but the system was bad.

I do have the VIS Vader hood, so I might have an unfair advantage. I see airflow patterns in the rain while driving so I know it is helping to remove hot air from the engine bay.

In my cooling system woes, I have found that air bubbles, pressure leaks, to be the greatest source of inefficiency. Be diligent about checking the overflow tank, if it ever becomes empty, then the cooling system will draw in air under normal expansion/reduction from heat cycles. Instead of pulling in coolant, it will pull in air.

Almost immediately after flushing/filling/burping the system, the cooling works amazing. As long at the overflow guarantees fluid return to the system, it still works amazing.

I have had some close calls caused by the reservoir slowly going empty, or the pinhole radiator leaks I had from physical damage.

Currently I run a mishimoto dual pass rad (not x line), pure 50/50 coolant, and the one OEM AC fan (working on fitting the drivers side back in) and it works just fine for now. Slightly colder that stock T-stat. Maybe 180*?

I have some other restrictions, as well as some improvements:
-Vader vented CF hood
-Custom AC front end (smaller condenser mounted further from the radiator
-ETS race FMIC, no bumper holes/vents.
-Removed PS "cooler" and a few brackets in the front end.

I rarely see above 200* anymore with the latest setup. I mostly hover around 190-196. I bet with the OEM drivers side fan I can get it to 180 rock solid.
 
If your cooling system works fine at highway speeds, and not fine during stop/go, you probably have a fan issue. Working effectively at highway speeds and sustained RPM engine heat production suggests it is capable of removing heat. I had the opposite problems, and deduced my fans were good, but the system was bad.

I do have the VIS Vader hood, so I might have an unfair advantage. I see airflow patterns in the rain while driving so I know it is helping to remove hot air from the engine bay.

In my cooling system woes, I have found that air bubbles, pressure leaks, to be the greatest source of inefficiency. Be diligent about checking the overflow tank, if it ever becomes empty, then the cooling system will draw in air under normal expansion/reduction from heat cycles. Instead of pulling in coolant, it will pull in air.

Almost immediately after flushing/filling/burping the system, the cooling works amazing. As long at the overflow guarantees fluid return to the system, it still works amazing.

I have had some close calls caused by the reservoir slowly going empty, or the pinhole radiator leaks I had from physical damage.

Currently I run a mishimoto dual pass rad (not x line), pure 50/50 coolant, and the one OEM AC fan (working on fitting the drivers side back in) and it works just fine for now. Slightly colder that stock T-stat. Maybe 180*?

I have some other restrictions, as well as some improvements:
-Vader vented CF hood
-Custom AC front end (smaller condenser mounted further from the radiator
-ETS race FMIC, no bumper holes/vents.
-Removed PS "cooler" and a few brackets in the front end.

I rarely see above 200* anymore with the latest setup. I mostly hover around 190-196. I bet with the OEM drivers side fan I can get it to 180 rock solid.
I think your Vader hood is helping out. I placed two new 12 inch spal fans so I'm reluctant to say that's my issue during stop and go. I think once I place that hood scoop I should be good to go but we will see. The prior eBay fans worked perfectly with my prior turbo and exhaust setup. This new setup is wrapped but closer to the radiator plus the addition of a fmic that is way way bigger ALL around. Stay tuned!
 
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