Cooling Fan to Radiator Sealing
Joe Angell
I’ve consistently had issues with my car overheating. It’s pretty good now, but it still gets hotter than I’d like.
John Dowd noticed that our cars tend to have not insignificant gaps between the cooling fans and the radiator. This means that instead of pulling air through the radiator, it would instead suck it through those gaps. This causes the car to run hotter than it really should.
John used adhesive-backed window and door insulation from the hardware store to seal his gaps, along with an aluminum “L” piece. We did the edges of mine with the same, but I still needed to do the bottom edge.
A few months later, I finally got around to it. I bought some slightly different adhesive-backed insulation, an expandable joint-filler style. The foam that this is made of compresses like the softer foam John used but seems to be a bit stiffer and more likely to seal the gaps. The stiffer foam should hold its position between the gaps better. Also, the stuff we put on before was a bit thin, and I had larger gaps that meant that we had to it a bit, and it had come loose after a couple of months of driving around. I bought thicker 1” foam to help with this, although I still had to stack it under the
The new foam seems to be holding well enough. I was also able to get it to fill the gap under the fan, while John added an aluminum bar to hold his foam in. Mine didn’t seem to need the bar.
After a summer of driving, I found that the temperatures were a little better, but it wasn’t super cold or anything like that. It certainly improves airflow on hot days. The most extreme was moving in slow highway traffic on a 95-degree day. With the A/C on full blast the fans still couldn’t keep up, and the engine temperature slowly crept up towards 220. With the cabin fan off, the engine temperature went back down to a more reasonable 205 or so (due to other ongoing projects I simply turned down the fan speed, which likely would have allowed me to have both some A/C and more engine cooling at the same time).
Frost King Expandable Self-Stick Joint Filler Weatherseal, 1” wide and 1” thick.
The gap below the fans filled with foam.
The gap on the driver’s side.
The gap on the passenger side.