My ongoing cooling problem.. help peas.
 

Well after getting all the air out of my system (i think) I'm still have abnormally high coolant temps.

Cruising around in the city, my temps are about 180-200F. Mind you its about 32-45 degrees outside. But the odd thing is, that on the highway my coolant temp actually goes UP to 210 and if I increase my speed to like 75-80, the temp starts to climb.

I'm running a Koyo rad and Trust IC.. Here's the best picture I have of the setup

https://www.rx7club.com/attachment.p...d=150661&stc=1

I don't have an undertray on the car either.. I have one from my old fd, but I don't know how well the stock undertray would do with that radiator setup. Any advice? This is really like the only quirk left with my car (right now).

The radiator is not ducted and has 1 cooling fan. I think it's obvious why you're having cooling problems.

Do you have any kind of duct that is directing air to the intercooler and rad? If not you should make one up. Also i would put the under tray back on. Mazda put it on there of a reason. It will help direct air through the intercooler. Also make sure your and s set to suck and not blow. Or maybe put it on the other side. These are just things I would try.

Hallman boost controllers rock!!! I dont now about your heating problem though. My guess is the shrould issue. You are not flowing air correctly i guess.

josh

ducting is the key to a good cooling system. ensuring proper sealing at IC-->Rad will give you lower operating temps.

puller fans are also more efficient than pusher fans, though it sounds/looks like you need to fix the ducting to be sure it is the main issue since it is a high load heat up not low speed.

Allright, thats what I was thinking but I guess I was just being retarded. Hopefully tomarrow after work I'll have time to throw the stock undertray back on, and try my best at fabbing something up to direct airflow a bit better. Thanks guys.

try some sheet metal.

Also, with or without ducting, a fan in front of the rad will restrict flow at higher speeds (say above 30 mph) more than a fan behind it. The fan really does need to be behind the rad.

get one of these bad boys too to eliminate the air pockets https://www.rx7club.com/showthread.p...ighlight=lisle

it sounds like you might still have some air in there. similar thing happened to me once on my last FD.

oh and duct that radiator.

Man, with all of the good advice about cooling systems on this board, you fabricate your radiator setup like that?

1. Mount both stock fans back on the radiator -- on the motor side!
2. Put your undertray back on.
3. Add ducting for a proper seal with the intercooler, although that's not your problem at the moment.

^LOL

not sure what you were thinking with that fan and the way its mounted?!?!

I agree with Alberto MG. You can pick one of the kits at Pep Boy(I did) for about $20 or so (IIRC). It will certainly do a good job of getting the air out of your system. That will be one less thing to worry about while you address the other issues. Good luck!

This is pretty common issue with fmic and verticle radiator. It doesn't matter how big your radiator is, if you can't get air in to cool it!

My fans are on ALL the time when my blk FD was running. Get rid of that single fan and put the stock fans back on. You could also go with both 4 blades or get 99+ fan blades. I'm going to run 2 x 4 blade fans on my car.. and also fab some sort of ducting to get some fresh air.

That FMIC is too damn close to the rad.

Yeah.. not my design at all. I bought the car like this (heh). I put the stock undertray back on, and got a new thermostat. Same problem. I guess I'll have to get more creative. I ordered the lisle funnel to hopefully remove any air thats left trapped in there.

Put the undertray back on. I took mine off once (don't ask) and highway driving continued to raise my coolant temps above 90 C.

When it put it back on w/ a Koyo, it stays between 70-80 C. I only hit 90+ C when I race.

I put it back on today, it didn't make any difference. =/

I'm at a loss. Sounds like you are having problems getting the hot air out.

Either that or getting it to go through the radiator itself. I have no clue.

have you tried putting the stock fans and fan shroud back on? I think that should be your next step.

You're going to have to do more than just install the undertray. The air can still go around the sides and over the top of the radiator. The key is creating a pressure differential across the radiator so that the air "wants" to make its way thru it. A setup like that is going to require some sheetmetal ducting in order to build up as much pressure as possible in front of the radiator.

On a side note...if your fans have to stay on at 25+mph with the A/C off then something is wrong with your setup.

is your fan pulling or pushing?

maybe you can feed fresh air into a duct for the radiator via the passenger side oil cooler duct (if you don't have an oil cooler there).

it will be hard get this set-up to run cool.

1) engine cold, verify coolant level is within 1" of the lower cap seal. If not, air or exh gas is entering system ... bad cap, hose to overflow, or coolant seals.

2) ALL air entering bumper mouth must be ducted to go through rad. Ok to bypass IC and actually some bypass is a good thing. Use cardboard/poster board and duct tape for quick test set-up. Should be cool above 30 mph.

3) single fan nfg. in traffic will just loop hot air in and out of rad. Use 2 fans, push or pull, with full shrouding like oem fans. summit sells some:

summitracing.com

flex-a-lite twin low profile pusher fans 10" or 12"

We have done many setups similar to yours with a koyo and front mount. We never have cooling issues even without the under tray or a duct directing air. I would put the stock fans back on, and its possible you still need to bleed the system.

Jason

i think that tiny ass pusher fan is problem #1.