To all you guys leaving the front of the radiator open, it's important you close it off so the air gets pulled through the radiator and not over it. I noticed a lot of guys taking off the plastic covers in the front.
The under pan and front covers aid in cooling.

Yeah, I'm still working on mine and just slapped the lower pan on for now. After the FMIC is installed, I'll either put the stock pieces back in or buy/make a new panel. And yes, those are magnacor 10mm's

Stock wires are more than enough.

Also, im running an 18in Thunderbird fan.

I dont think those covers are all that important... With the Koyo I have and a crappy Autozone Imperial E-fan, I rarely got to 180...


I also have neither the top or bottom cover on...

A fair E-fan will overcome the lack of ram air ducting, but it will run longer duty cycles, taking more power over time from the alternator.

The covers and undertray significantly increase the efficiency and capacity of the cooling system. Air always follows the path of least resistance. Without them there the easiest path for the air to take is above and below the radiator, not through it. The more air that's being forced through the radiator, the less work the system needs to do at light load and the more heat it is able to remove at high load. Simple physics.

I don't understand why people take them off in the first place. It's not like they weigh anything. :confused:

I don't understand how you guys are running like 160-170...

it should never be below 180-185 with a stock thermostat... (in the water pump housing)

I don't know what problems I have. but my setup is just not working... with the k2rd rad (looks the exact same as your howe) and peramacool 16" 3000CFM fan

I run 190-195 on the highway. and when I come to a stop at 190. it'll idle up to 200. my fan turns on around 190 and it'll never turn off while I drive. and when I stop it'll stay running for 10 mins.

mazda thermostat and coolant have been changed twice in the last year with no change. as well as the water pump.

I'm still on the stock motor with 109k so maybe it's just getting cloged up on the inside... I don't know. I'm not losing any so I don't think it's a coolant seal. that's normaly alot worse overheating wise.

I pulled my e-fan off last weekend and put the stock one back on with *no* shroud (so the fan sits 4-5" away). and it's a bit better I think then the e-fan... which shows you how much better the stock fan is. I should have a custom shroud on by the weekend which I'm hoping will make it much better.

and then I'll have a big post about how much better the stock fan is :)

last year with my stock fan, rad, and shroud. it would idle at 185. but it would get hoter then now climbing hills on the highway.

This is true. An upgraded radiator (or any other cooling system mod) should only lower temps from if they were hotter than normal to start with. You're only supposed to increase the cooling capacity, not make the engine run cooler than it's supposed to.

"I don't understand how you guys are running like 160-170..."

I'll put my $.02 in here also. I agree that this is not as easy as it appears. I've been working on mine for a year to get it to run like I think it should. I have a full custom shroud and I know my cooling system is clean. I can maintain 180 - 190 temps but my fan runs more than I like.

Rb

I have a Fiero fan and two bottles of Water Wetter in my coolant mix.

My temps drop as low as 165F travelling at 120km/h in 5th (low revs.)

In traffic she's between 175F and 190F (when the fan kicks in.) My temps are generally slow to rise if she's sitting idling.

Last summer I did the modified coolant flush twice as well as replaced the thermostat in an attempt to deal with higher-than-I-was-comfortable-with running temps. Now I sometimes wonder if she's running a little cooler than she should. :) I'll take cooler over hotter any day.

This is with all of the shrouds in place.

Im not saying that they dont work...and I do understand how they work...All Im saying is that mine are both gone and I rarely see 180/190 with a crappy Imperial E-fan. Now the car has a Black Magic fan on it and no real coolant temp gauge so I cant see what it is exactly anymore.


As for removing them, I didnt. I bought the car with them gone.

Your bigger radiator probably helps quite a lot then. I know that people with stock cooling systms have cured overheating problems by reinstalling them. And that's cheaper than a new radiator... ;)

Now that summer has come to Tejas with a vengence....the water temps tend to run at 195 at 70mph. Not worried. They say that the engine is more efficient at the upper temps. Just a week ago we had a cool spell where the temps fell to the mid 80's and the temp at 70mph was b/t 185-190. Got me a Autometer water temp gauge. It seems fairly accurate. Gonna put it in a pot of boiling water this weekend to see just how accurate. My mechanical gauge(aftermarket gauge) seemed to be off by seven to ten degrees to the cool side.

As a side note, my mechanical gauge is installed in the electric fan sensor location after the thermostat. It will be moved into the water pump housing later if I see a huge difference in temp on the stock temp sendor once the microtech is installed. My guess, it's probably just about right. As increasing cooling capacity to keep temps where they're suppose to be...a radiator can create over cooling. The absolute max that it can cool is obviously the ambient temp and with more surface area and twice the volume...it should be possible to bring the temps WAAAAAY down. Hell, in the winter, I don't think my dad's lightning gets up to thermostat temp and that's with cardboard blocking 1/2 the radiator. Now that's a chilly ride in the winter.

it will bring down temps in the rad and hoses... but when the temp is under 185. the thermostat is closed. and no water is leaving the engine. so the engine side of the thermostat will never be under 180-185. but it will be in the rad.

but you explained it by saying you were on the rad said of the thermostat. that is why you are getting the lower temps.

That's not right. The thermostat's job is to keep the temp within the temperature range that the engine operates best in. If you install a larger radiator, then less flow is required through the radiator to keep the coolant temp where it was before. The thermostat should operate in exactly the same manner no matter what the radiator size, and keep coolant temp reasonably constant. It's not supposed to be way down.

okay, well it should keep it at the point that the thermostat starts to open...hows that. I was speaking in an uncontrolled cooling system. IE..if you have the cooling capacity and the engine runs at X temp, there will be a max that it can cool. That would be your cooling capacity...if it would always stay below thermostat temp, then you can have full control over the temp by selecting different thermostats and not have to worry about it creeping up. In my case, I wonder if once it opens @183, if it's hard for it to shut all the way when it's pressurized? Obviously coolant is running through the system as the radiator gets hot.

"I wonder if once it opens @183, if it's hard for it to shut all the way when it's pressurized? "

The pressure drop across the thermostat is negligable. With the exception of the output pressure of the water pump, it sees the same pressure on the upstream side as it sees on the down stream side. So no it doesn't have a hard time closing.

Rob