60+ mph cooling problem

[Slow99x]

My 2g is running hot on the highway at 60+ mph. I have both fans connected but I've heard that they don't really do anything over 30 mph. This problem does NOT occur when just driving around town or sitting in traffic. It seems to only happen in fifth gear at 60 or higher. I do have a FMIC but I have also removed the AC to get more air through the radiator and it helped but did not get rid of the problem. My water pump is new and I have just gotten a cooling system flush to get rid of any debris but the problem persists.
I was thinking of running a duct from the side vent where the SMIC used to be to get more cool air to the radiator instead of the hot air comming through the FMIC. Any tips or advice would be helpful.

 

[TurkF26]

either A like you suggested its not getting enough air or B your radiator is crap and its time to upgrade to an aluminum one. i can hook u up so let me know if you need one.

 

[Slow99x]

I don't know if an aluminum radiator would solve the problem. Like I said, it doesn't get hot driving around town or sitting in traffic. In fact, when it starts to run hot and I get off the highway and stop but the motor is still running it will start to cool down.

 

[blue92laser]

That would narrow the problem down to the radiator not getting enough air...wouldn't it?

 

[Slow99x]

That 's what I thinking but I wanted some other opinions as well as some possible solutions from others that maybe had the same problem.

 

[EZ91Talon]

Is your heater core bypassed? Have you tried touching/grabbing the upper radiator hose when the engine first gets hot to verify that your thermostat is not sticking (if the engine is hot this hose should be too hot to hold)? Think about the path of least resistance for the hot coolant exiting the block/head/intake (just below the thermostat) and then trying to enter the water pump inlet pipe (running between the block and the exhaust). For proper cooling, the easiest path MUST be through the radiator. If the radiator is NOT the easiest path, the water pump will pull it from elsewhere (heater core line, turbo line) and keep re-circulating the same hot coolant. Heat transfer requires time. At low RPM's (idle) there IS minimal time for the fluid to radiate heat through the walls of the inlet pipe (aluminum radiates well) and wherever else it can to provide MINIMAL cooling, but at freeway speed (+/- 3K RPM's ?) the coolant flows too fast and you get NO cooling at all.

 

[Tarantula]

Is your heater core bypassed? Have you tried touching/grabbing the upper radiator hose when the engine first gets hot to verify that your thermostat is not sticking (if the engine is hot this hose should be too hot to hold)? Think about the path of least resistance for the hot coolant exiting the block/head/intake (just below the thermostat) and then trying to enter the water pump inlet pipe (running between the block and the exhaust). For proper cooling, the easiest path MUST be through the radiator. If the radiator is NOT the easiest path, the water pump will pull it from elsewhere (heater core line, turbo line) and keep re-circulating the same hot coolant. Heat transfer requires time. At low RPM's (idle) there IS minimal time for the fluid to radiate heat through the walls of the inlet pipe (aluminum radiates well) and wherever else it can to provide MINIMAL cooling, but at freeway speed (+/- 3K RPM's ?) the coolant flows too fast and you get NO cooling at all.

I have the Same Exact problem. At 70mph I get to 222F. Slow down and it gets cooled off quickly. driving at lo RPM's I have not one problem. I too have a FMIC and Ducting behind FMIC and infront of the Condensor/radiator that I fabed up using sheet metal. My Radiator hose does feel very hot. I did 2 flushes, and run Water wetter/Distilled water. I changed the Radiator cap and the Thermostat I also changed to a new Stant 170 degrees. (I verified that it worked before I installed it by boiling it in hot water.) I read this post but don't really get what is your point or how is this info useful in figuring out what action to take to correct the problem. Are you saying that the coolant needs to move slower at 3K+ speeds? If this infact is what you are saying (and yes it does make sense) How do We go about doing so?

 

[EZ91Talon]

I had this problem but in my case it was a combination of a crappy (adjustable type) thermostat and a bypassed heater core. If your upper and lower hoses are hot, the coolant is likely circulating through the radiator, it sounds like you have airflow issues...

I am sort of new to DSM's but I know in other applications some cooling issues are cured by choking down the water pump inlet to reduce the volume (especially if high volume components have been added) of coolant flow and allow more time for heat transfer from metal to fluid and vice versa...

 

[Tarantula]

Heres what I found with my car. With stock thermostat 180 and both fans running at idle temps stabalized at 206. Did not go up or down. Reved the motor for a minute to 3000 rpms and temps drop to 203 but shortly went back up to 206 after letting it idle. Went out to feel the air flow between the two fans. Warm air but on the cool side. Squeeze the upper hose. A little squishi.
Turned off both fans to let ecu take over. goes up to 210-213 fans cut on. shut off at 199. Cycles between these temps. Airflow really hot and upper hose rock hard. Driving a steady 70 for 20-30 minutes temps stabalize at the same 206 with both fans running. Fans off and we already know... 222F
Now Stant 170 thermostat with a hole drilled into it. Both fans running at idle temps stabalize at 192. Did not move from there. Reved the motor to 3K. Temps droped to 186. Back at idle temps raise to 192. Airflow same as above and upper hose same as above. Shut off fans and same cycle between 213-199 and hose rock hard. Went for a drive With one fan running steadily temps stabalize at 210F. Both fans running temps stabalized at 192. Climbing up hills with boost temps raise to 210, than drops back down to 192-195 with a low of 186 if I hit a lot of traffic lights.
Well this confirms that airflow is my problem. I do have both fans wired to run on high speed. They are wired to a switch to ground any of the relays I choose. If I want 2 fans running I just move the wire to pin 1 on Hi relay(2nd relay from the left). One fan move wire to pin 1 on lo relay(4th relay from left). The other hi relay (3rd from left) inbetween hi and lo runs only runs the AC fan on high.
It was a little cool out so I'm going to keep the 170 Stant in place to see if the temps will stay that low on a really hot day and with AC running. I also learned that with fans rnning continous keeping water temps stable or low, pressure does not build up so much. Can't explain that one. I also cant explain why temps stabalize at 206 with stock thermostat and fans steadily running and if fans work normal with the ecu controlling, temps will lower to 199 before raising up again to 213 for the fan to turn on again and that keeps going in cycles. So it is narrowed down to airflow. Now I am just wondering it 192 is too cool for continuous engine temps.

 

[blueberry_dsm]

the radiator not getting enough air has nothin to do with it. if it can sit in traffic with hot exhaust pumping on it, then driving at 60mph with an ass load of air flowing into it, the radiator ad fmic shouldnt have anything to do with it.

 

[Tarantula]

the radiator not getting enough air has nothin to do with it. if it can sit in traffic with hot exhaust pumping on it, then driving at 60mph with an ass load of air flowing into it, the radiator ad fmic shouldnt have anything to do with it.

Do you even know what you are saying? The radiator needs airflow through it to cool the engine coolant temps down. Under stock applications airflow is plentiful as there are no restrictions. With a SMIC same applies, no restrictions. Now witha FMIC theres an airflow restriction. DSMs do not have a very large opening for air to flow to the radiator. Put something in front of it and air slows down. That and higher power, bigger turbo etc will cause more heat to be made from the engine. So now more heat and less airflow = Cooling problem! That is what we are discussing

 

[EZ91Talon]

The engine is under more load at 60MPH than creeping in traffic. More load = more heat generated. Found this link searching for "overheating AND speed AND fmic" ... good stuff: http://www.dsmtuners.com/forums/showthread.php?t=152625&highlight=overheating+speed+fmic

 

[Slow99x]

I have the Same Exact problem. At 70mph I get to 222F. Slow down and it gets cooled off quickly. driving at lo RPM's I have not one problem. I too have a FMIC and Ducting behind FMIC and infront of the Condensor/radiator that I fabed up using sheet metal. My Radiator hose does feel very hot. I did 2 flushes, and run Water wetter/Distilled water. I changed the Radiator cap and the Thermostat I also changed to a new Stant 170 degrees. (I verified that it worked before I installed it by boiling it in hot water.) I read this post but don't really get what is your point or how is this info useful in figuring out what action to take to correct the problem. Are you saying that the coolant needs to move slower at 3K+ speeds? If this infact is what you are saying (and yes it does make sense) How do We go about doing so?

Any pics of you ducting? It doesn't have to be pretty but I am interested if it is functional.

 

[Tarantula]

Any pics of you ducting? It doesn't have to be pretty but I am interested if it is functional.

Go to post 11 here and check it out. there are 2 pics there.

 

[Slow99x]

Is the theory behind this ducting that it will work like the radiator shroud at the top by the hood latch to direct the air flowing through the FMIC or is it the gaps between the foglights and the end tanks that gather air and direct it to the radiator?

 

[Tarantula]

Basically the idea was to make the shroud so that the fmic is there. I cut up the shroud the first time and noticed that it was a mistake. The air that flows into the mouth will go all over the place, either through the fmic or the 2 holes by the end tanks. so I wanted a "no escape but through the radiator" type of shroud. The original stock shroud still has the sides in tack, just that I cut the front half to fit the fmic. This new shroud I made sits right up against the fmic.

 

[Slow99x]

Very interesting. Have you noticed a difference? Now that you mention it, I did notice this started happening after I had cut the top part of the "mouth" to expose more of the FMIC. I guess that this portion of the bumper was forcing more air through the intercooler instead of over it because the A'pexi core is just tall enough to let air over if this peice is cut. I'm going to try your solution plus some ducting from the stock sidemount location for extra insurance because an overheat going to or from the DSM shootout would suck.

 

[Tarantula]

Not that much of a difference. At low speeds its fine. just higher speeds (Havent you read this entire thread?)
Now I"m thinking of cutting the metal bumper holder that holds the 5 bolts to the face in the center. I have a gap between the hod and the face. Maybe I'll fabricate a shroud to direct flow to the upper top part of the radiator. I have to but the shroud where I will be putting the new ram shroud between the hood and face. I'm still planning on doing this but not so sure how yet. I just know I need more air.

 

[Slow99x]

I did read the posts several times but I was asking if this shroud did anything on its own. In your longer post you mention alot of temp changes but you didn't exactly say what happened before and after you installed this on its own or if you added the shroud along with the thermostat. i'M thinking about wiring my slimline to a switch inside the vehicle so I can turn it on when I'm on the highway and off when around town.

 

[Tarantula]

The shroud by itself did nothing to change my situation. The thermostat did nothing either. What made a difference was the switch to run both stock fans and the pusher together while on the freeway. Today I tried the ac test. Well it took a while but going up a slight incline with the ac on the temps reached 222F. Thats when I shut off the ac. Thats with the fans running constant. I just need more airflow. I have never had any problems before the fmic install.
Today was a hot day. With the fans running constant and no AC it was 203-206 steady 80mph.

 

[Slow99x]

I think I'm going to try the fan running on the highway first anf then the ducting. I'll keep you posted on the results.

 

[hellraz0r1337]

on my 2g its completely stock except for inner cooler pipeing thats it when i drive my car on the highway or anywhere the tempature of my car goes to about 3/4 of the guage and holds solid doesnt over heat but when i turn my heat on it drops back to 1/2 which is good i guess if i wnated to drive around in 70 degree weather with my heat on but besides that,

i ran my car let it heat up and when i parked i noticed my top hose was warm not ridiculously hot but decent to where i wouldnt want to hold it and the bottom hose felt like there was no coolant in it at all felt like it was just put on my car.... now that scared me a little bit becuase that hose should be hot right? and if so what the hell could be my problem which way does the coolant flow from the bottom hose in to the top hose out ?

 

[gsnoturbo90]

theres no leaks in the radiator right? IS there a way you can take a picture of your engine bay and show everyone maybe there an obstruction that can easily be fixed

 

[hellraz0r1337]

no i cant take any pictures and i dont see any leaks my overflow tank has fluid it in when you squish the hoses you can feel / hear liquid i dont understand what is wrong here.

 

[Tarantula]

Not that much of a difference. At low speeds its fine. just higher speeds (Havent you read this entire thread?)
Now I"m thinking of cutting the metal bumper holder that holds the 5 bolts to the face in the center. I have a gap between the hod and the face. Maybe I'll fabricate a shroud to direct flow to the upper top part of the radiator. I have to but the shroud where I will be putting the new ram shroud between the hood and face. I'm still planning on doing this but not so sure how yet. I just know I need more air.

Well just wanted to update on this idea. I made a cut and installed a fabricated sheet metal shroudlike thing to direct airflow to the radiator straight from tha area between the hood and face of the car. It did nothing to improve. So the best thing that actually helped was wireing the fans via a switch to ground the hi fan relay pin 1 and turning it on to run constantly AFTER the car has warmed up to at least 199. This keeps my temps at 199-206 whether on the freeway or not. Even hitting turbo multiple times keep my temps below 213. it would only touch 213 than drop down again. At idle it stays a rock steady constant 206.