Sealing gaps around radiator

[EcoCivic]

Hello everyone, I have been working on a project that some of you may find interesting. As you can see, my 2005 Civic had pretty sizable gaps between the sides of the radiator and the radiator support. There are several problems with having gaps around the radiator:

1. Air takes the path of least resistance. The path of least resistance isn't through my trans cooler, AC condenser and dual row radiator. Sealing those gaps helps force the air through the radiators rather than allowing it to go around.

2. When sitting in traffic with the fans on, some of the hot air that the fans push into the engine compartment can go through those gaps and get back in front of the radiators, reducing their effectiveness. With the gaps sealed, the fans will only pull cool air in through the grill and can't recirculate hot air from the engine compartment.

3. Any air that gets into the engine compartment pressurizes it. This is bad because higher pressure on the back of the radiator and fans inhibits airflow through the radiators, decreasing cooling capacity. Ideally the engine compartment would be under negative pressure but realistically that won't happen, so we want as close to zero pressure as possible for the best airflow.

4. Air flowing through the engine compartment creates drag and should be minimized where possible for the best efficiency. If air is flowing through the engine compartment it should be going to good use (cooling the radiators).


My solution was to cut pieces out of a sheet of aluminium that I have and use self tapping screws to secure it to the sides of the radiator support. To prevent vibration issues and rattles, I left a small gap between the aluminium plates I made and the sides of the radiator and covered that small gap with foil HVAC tape. I also sealed off some other random holes with that foil HVAC tape while I was in there. Easy, simple, and free When I reinstall the bumper cover, I am also going to use a piece of foam to seal the upper grill to the top of the radiator so air can not go over the radiator.

Once I fabricate and install a shroud for my dual Spal radiator fans, I will be ready to put the bumper cover back on. But before I put the bumper cover back on, I am going to fabricate some ducting that extends from the radiator support to the inside of the bumper cover. This way all the air that goes through the grill openings will be forced through the radiators and can not go around and escape through the wheel wells, under the car, etc, which accomplishes nothing other than create drag. I know that probably doesn't make much sense, it will make more sense once I do it and upload pictures.

I am also planning on moving the radiator forwards about 1/2 of an inch so it is closer to the AC condenser and to give me a little more room to access the front of the engine. My understanding is that the radiator and AC condenser should be as close together as possible without touching for maximum cooling efficiency so the condenser doesn't deflect airflow around the radiator and so the radiator fans pull all their air through the condenser instead of being able to pull air around it.

I feel confident that all of these enhancements together (sealing the gaps around the radiator, installing ducting, and moving the radiator closer to the condenser) will result in a decent improvement in my cooling system's capacity, slightly better AC performance at idle, and a tiny decrease in aerodynamic drag. My intake air temp didn't increase either because I built a heat shield for my air filter to separate it from the rest of the engine compartment. As always, any thoughts or comments are always welcome and appreciated!

[California98Civic]

I like it. I did something similar with HVAC aluminium tape, foam, and leftover aluminium serving trays from an event. Helps. Needs some adjustment and repair now. Next time I have the bumper cover off....

Report back any improvement in cooling?

Subscribed.

[EcoCivic]

Originally Posted by California98Civic

I like it. I did something similar with HVAC aluminium tape, foam, and leftover aluminium serving trays from an event. Helps. Needs some adjustment and repair now. Next time I have the bumper cover off....

Report back any improvement in cooling?

Subscribed.

Thanks. Honestly with my Mishimoto radiator my cooling system worked so darn well the way it was that I wouldn't see the improvement, even on a 100 degree day with the AC on the coolant temp sits right at the thermostat's temp of 182-186 degrees like it does in the winter. Without a thermostat, my cooling system would actually overcool the engine down to about 160 degrees even driving down the highway using the AC on a 100 degree day, which is darn good IMO.

I suppose once I finish my fan shroud, install ducting, and reinstall the bumper cover I will pull the thermostat out again and see if the cooling system could cool the engine even more after these mods, I think it will. Did you notice a cooling improvement when you did this?

[California98Civic]

Originally Posted by EcoCivic

Thanks. Honestly with my Mishimoto radiator my cooling system worked so darn well the way it was that I wouldn't see the improvement, even on a 100 degree day with the AC on the coolant temp sits right at the thermostat's temp of 182-186 degrees like it does in the winter. Without a thermostat, my cooling system would actually overcool the engine down to about 160 degrees even driving down the highway using the AC on a 100 degree day, which is darn good IMO.

I suppose once I finish my fan shroud, install ducting, and reinstall the bumper cover I will pull the thermostat out again and see if the cooling system could cool the engine even more after these mods, I think it will. Did you notice a cooling improvement when you did this?

I did think I noticed an improvement. My temps were better and I needed my fan less often. But it was not an objective test. Just my sense on my daily commute, which I have done the same way in the same car, on the same route all week for 11 years now. I felt confident it was a good mod.

A half inch between the radiators sounds right to me, btw.

[EcoCivic]

Originally Posted by California98Civic

I did think I noticed an improvement. My temps were better and I needed my fan less often. But it was not an objective test. Just my sense on my daily commute, which I have done the same way in the same car, on the same route all week for 11 years now. I felt confident it was a good mod.

A half inch between the radiators sounds right to me, btw.

That makes sense, if ram air cools the radiator more effectively after this mod then the fan wouldn't be needed as much to draw more air through.

Vintage Air and Griffin Radiator both recommend 1/4" to 3/8" of space between the condenser and the radiator with 1/2" as an absolute maximum. Makes sense to me. If the condenser is too far away from the radiator, the radiator's fans will pull a lot of air around it rather than through it and the condenser can deflect airflow around the radiator.

[EcoCivic]

The only disadvantage to this mod that I can think of is that you may increase your intake air temp depending on how your air intake is set up and where it gets air from. I noticed no change in my IAT because my custom cold air intake draws air from behind the passengers side headlight and I made a heat shield to separate it from the rest of the engine compartment, but this is something to keep in mind if you are planning on doing something like this.

[me and my metro]

This is a great thread, thanks. I work on trucks mostly and need to blow out the straw and leaves the accumulate between the condenser and the cooling package on my trucks. The factory does a great job of sealing everything on the Ford trucks I work on. To the point of it being painful to get it right after replacing a radiator. To be honest I have not even looked at my Saturn to see if it would gain anything by sealing this.

[EcoCivic]

Originally Posted by me and my metro

This is a great thread, thanks. I work on trucks mostly and need to blow out the straw and leaves the accumulate between the condenser and the cooling package on my trucks. The factory does a great job of sealing everything on the Ford trucks I work on. To the point of it being painful to get it right after replacing a radiator. To be honest I have not even looked at my Saturn to see if it would gain anything by sealing this.

Yeah I imagine much more attention is paid to details like this on trucks since they are designed to haul heavy loads, which creates a lot of heat that needs to be dissipated. On a heavily loaded truck running wide open up a long steep grade in 110+ degree heat, these little details could possibly be the difference between the truck making it to the top without a problem and overheating to the point of something failing. Not that I would ever heavily load my car up a steep grade... https://ecomodder.com/forum/showthre...gle-37994.html

[Ecky]

Nice mod!

What's this about removing the thermostat though? Why would you do that?

[EcoCivic]

Originally Posted by Ecky

Nice mod!

What's this about removing the thermostat though? Why would you do that?

I just took the thermostat out to see how well the radiator and cooling system worked, and I think the fact that it can significantly overcool the engine driving down the highway with the AC running on a 100 degree day means it works pretty darn well. I normally run a thermostat. Once I get everything finished and put back together I will redo that test on another ~100 degree day and see if it can cool the engine off more. If it can that means my mods worked.

As effective as my cooling system is, I can't judge its performance with the thermostat in since the coolant always runs right at the thermostat's setpoint of around 182-186 degrees all year, doesn't matter if its the middle of the winter with the heater on or a 100 degree day with the AC on.