JWS6

So it gets REALLY hot here in Vegas and I've been fighting overheating for three summers now. I noticed I don't have the 2 flaps on my fan housing so I need to fab something up. Are these supposed to be closed when the fans are on and flexible enough so they can "open" when the car is at speed?
I just upgraded to the Meziere HD pump, had my radiator cleaned up, blew out a ton of rocks from my AC condenser, and put a 1/8" hole in the thermo to help with air pockets. Car runs great at highway speeds but the temp really starts to climb in slow traffic with the AC on. This sounds like a lack of airflow problem to me. I'm on the fence about installing a pusher fan to try and help get more air through the radiator and I'd like to try and NOT have to buy a Becool radiator. Any suggestions/experiences would be great. I know there is going to be a flood of overheating post in the next few months. BTW YES-the fans kick on, fans are tuned, 160 thermo, minimal antifreeze, watter wetter coming when blower is reinstalled(used it before), lower air dam on........TIA

JP95ZM6

How hot in traffic?

Yes, sounds like idle airflow is the issue. If you want to keep it cooler in traffic with the stock radiator, you either need more airflow, or cooler air at the radiator inlet, which means reduced recirculation. In other words, allow less of the hot exit air to wrap around to the front. The airdam helps, but there is also benefit in improving the sealing around the radiator. Filling in the gaps with foam will help some. So would lowering the airdam closer to the ground. Also check the voltage at the fans with them running. If more than a volt or so below alternator/battery voltage, there is benefit to be had by improving the wiring.

Regarding the velocity flaps, my stock 95 fan shroud does not have them either. Factory must have cancelled them at some point. My fan shroud has a flange feature molded around each 'flap opening' that seals that area off from the rest of the fan shroud. That makes the associated areas of the radiator 'ram air only', ie the fan cannot pull air through those spots. I suspect this flange was added when the flaps were cancelled.

Just adding the flaps might help a little bit at idle, due to eliminating the recirc path through those openings. For a larger improvement, add flaps AND trim the flanges back, or drill holes through them, so the fan can also pull air through those spots. The material needs to be light and flexible. Something like a piece of thin rubber, maybe even inner tube from a tire if you can find a flat enough piece. The more light/flexible, the less airflow they will cost you at higher speeds, since they will open more easily to improve the ram air component.

You can run 40% antifreeze/60% coolant to get slightly better heat transfer in AZ as long as the pressure cap is good.

If all this fails, bigger fans. For a cheap upgrade, you may be able to find a higher powered motor that will bolt in from another GM vehicle. I don't know which model to recommend, though.

Hope these things help.

1racerdude

Do ya have the flap underneath installed? The one that hangs down right in front of the rad underneath the car. The scooper.

JWS6

Air dam is installed. I'm kinda lost about the flange feature. Do you mean the molding is perpendicular between the shroud and the radiator around the two openings? I do plan on getting some type of rubber to seal the shroud to the radiator. I dont think recirculation is a problem when the blower is installed because the intercooler blocks everything in and the hot air CANT get out!!! Thats another issue but I'm trying to square things away before the blower is installed.

JP95ZM6

Ahhhhhh. There's your problem. You will need more powerful fans then, to bring your airflow back up to spec.

I didn't realize your intercooler was in front of the radiator. I assumed it was the horizontal kind off to the sides.

JWS6

it is the horizontal kind, three row to be exact but its not on the car right now....

JP95ZM6

Ok, your post was a little confusing on the intercooler issue. I see.

You never answered the how hot question. If less than the red zone, it's probably normal in LV city traffic with a/c on.

As for the flange, yes, I am referring to the 'boxes' around the flap openings, with walls perpendicular to the radiator.

Blower does cause your car to make more heat even at idle, due to the extra load to spin the blower at least. I don't know if that is enough to make a significant difference. I still think the issue is airflow. Optimize as much as you can with these fans, and see if it's enough.

JWS6

Im doing my best with what I've got. I'd like to find some specs on blower motors for the fans. I saw some fan motors on ebay for GM trucks that look very similar. I just wouldn't know if they are more powerful.

JP95ZM6

I searched for 20 mins on google, and I couldn't find documentation of the stock fan power or current. But I believe it's around 400W total for both. Some of the new GM trucks (HD, Diesel) have like 700 or 800 W total. If you have a 20A meter, you could check each motor individually to see current, then multiply by volts for watts. A good motor rebuild shop (electrical, like starter/alternator shop) will probably be able to tell you what motors are more powerful and will fit.

Might try a fan upgrade search or question in Electrical.

joeSS97

Do you have the correct t-stat? There is a difference.If so,I would drill a few more holes in the stat to get more flow.You can always swap it out in the winter.Something to think about and cheaper than a radiator.

Z-RATED94

How hot is it, when sitting still?

Denny McLain

If your running hot now and the supercharger is not installed, what do think is going to happen when you hook the supercharger up?? Several people in the Dallas area which isn't as not as Vegas ended going back to N/A as superchargers take more power to run than your air conditioning does. Like running two air conditioners at the same time or worse.

Also somethings up at low speeds as mine with the electric water pump actually cools down at idle vs driving. Got a Be Cool radiator and dunno...have to say it was margional. Hard to tell as I've had it a while and have opened up the front of my car more to get more air in...so??? Maybe??

It was 90 degrees yesterday according to my thermo on the hwy and was the first time I've seen 180 degrees this year hitting it real hard getting on the hwy going to 7000 rpm in 4th. It 398ci and 12.8 compression.

Don't want to be the person to pass the torch of bad news but you may have some issues with the blower. Good Luck!!

JWS6

The other day I drove across town with the AC on, freeway driving. Once I got off the freeway I pulled over to a gas station and let her idle for 10 more minutes with AC and the gauge was reading 210, so I shut down. I shut down because I was on the other side of town and just redid my cooling system so I didn't want to find out exactly how hot I just see where I'm at now and know when I put the blower back on its game over with the AC. I dont want a repeat of last summer when there was a car fire on the freeway and I'm running my heater in 115* weather I'm convinced its due to lack of air flow when idle, regardless of blower or not. I also want to retain the factory fan shroud due to expenses and I dont want to introduce variables. So I guess I'll have to find some more info on the fan motors and make sure to seal everything real good.

1LESSZ28

I think more powerful fans would certainly help along w/ purple ice etc. and a 160 tstat w/ fan reprogramming.

Not sure of what kind of aftermarket fan to recommend though as I am in the market for one. same problem as you are having. can anyone recommend a more powerful fan for the lt1 radiator and are they effective?

JP95ZM6

210 is not very hot, that's pretty normal for idle a/c conditions on a hot day. With a/c off and stock program, your fans wouldn't even be on yet. So, I don't think you have any cooling problems, so to speak. You will need a lot more airflow to keep the coolant temp in the 160 - 180 range under those conditions, if that's what you are looking for. Blower or not. I'd look into higher power fan motors that fit, then go to the J-yard for parts, for best bang4buck.