Recently I have been looking for a replacement for the existing Honda civic radiator that I have had in the Omni. The only reason I have been looking is to have some more volume of coolant in the radiator to increase some resistance to temps rising while sitting at a light in the summer sun. Typically it would run anywhere between 194-210 degrees while sitting, there was a couple of times it would get close to 230-235 and to me, that just seems too hot. As you know, the pressure from it getting too hot will push coolant out of the overflow tank and make a big mess.
I have been looking around for months to find a radiator that would:
1. Fit my car (which seems to be a lot more difficult that I would have thought)
2. Be at least marginally larger to hold more volume of coolant.
3. Have inlet/outlet sizes that are compatible with my existing hoses.
4. Be of high build quality so it can handle tons of abuse.
Finding the perfect radiator seemed to be impossible to do, aside from having a custom radiator made for me, which is extremely cost prohibitive. The issue I have been running into is the height requirements. I have to stuff my radiator under the factory radiator support due to the large intake plenum I am running. You can see in this picture, just how little room I have, and this doesn’t show you how much flex the mounts have under load.
I know this doesn't apply to everyone's installation, but I think this write up will help you guys out when finding cooling solutions for your high output Omnis along with other custom radiator installs. So, let's get this thing started shall we?
First thing I would like to do is give you guys a link to the radiator I found. It's a Mishimoto unit intended for a Mitsubishi Evo 7/8/9 2001-2007 This is a half sized radiator that I run on its side. Now this doesn't affect my cooling system as I have a filler cap on the head due to running a neon DOHC head. The great thing about Mishimoto radiators is, they offer a lifetime warranty that even covers car accidents! Here’s a link to the radiator:
http://www.mishimoto.com/mitsubishi-...tor-01-07.html
As you can see, it's a very well built radiator. the overall size is 14.0x19.5x2.05 compare that to the Honda radiator I have now 14.25x16.5x1.75 You can see that we have a bit more volume with the Mishimoto unit. Also, the Mishimoto radiator is a 3 core, while the ebay civic radiator is a 2 core.
Enough about all of that, let's get that Honda radiator out. You can see in this image that I have blacked out the Honda radiator for esthetic purposes.
You can see, I need to get that intercooler out of the way, as well as the grill, headlight bezels and bumper. I could have taken the intake manifold off, but I decided to take it out of the front instead. First, I removed the headlight bezels and the grill, my removal is slightly different than what yours might be, but I added my steps for your information. You can see the screws that need to be removed here:
There are these same ones on the other side as well (as you might already know) Then there is one tucked under the bezel shown here:
My grill is customized, so all I have are the 2 screws up top to remove it, so after these steps, the headlight bezels and grill came right out. Then I removed the bumper, all you have to do is remove the ends and 4 bolts to the sub frame and it comes right off. It takes one 13mm nut on each side to loosen the end caps on the bumper, then they slide out and forward to remove them
After those are all removed, the bumper should come right off.
Since my intercooler is a bit different than most of yours I'll spare you the details of removing it. The removal of my existing radiator is simple, it was basically "pinched" between the upper and lower radiator supports with some rubber guards, so it pulled right out, but make sure you drain your coolant before removing your hoses. most radiators have a drain valve. Make sure you have a container large enough to catch the coolant, mine was about the perfect size for my setup:
The drain valve on my radiator wasn't quite low enough to drain all of the coolant, so I removed the lower radiator hose to finish draining it.
Once everything is drained, you can remove the upper radiator hose and remove the radiator.
My radiator had a 12 inch Mishimoto cooling fan installed so I had to cut the mounts for it, to install it on the new radiator.
You can see the size differences in these images:
The Honda radiator was slightly taller than the Mishimoto radiator, so I had to space it up slightly to get it to fit properly. I currently have some foam stuffed under it and it works fine.
Now that it is set in place, we need to support the upper portion of the radiator to keep it from falling out. This radiator comes with a mount that works for the Evo, but doesn’t work so well for my particular installation, it could work for yours. I used 2 bolts with rubber protection to keep from damaging the radiator itself.
You can see here that the existing radiator hose doesn’t fit, I tried looking at several auto parts stores and there wasn’t a suitable replacement so I had to customize my existing hose by making it shorter. The lower radiator hose went right on.
Next we’ll fill it up and check for leaks. I didn’t observe any leaks after filling mine up.
After all of that, here are a couple of shots of it installed and ready for some testing.
Here are some comparison shots of the Honda radiator vs the Mishimoto replacement. First, the civic radiator:
Next, the Mishimoto:
After I finished the installation, I wanted to see if I could get it to overheat. I started by idling in my driveway for a LONG time, it wouldn’t get more than 176 degrees, so I brake stalled it to build up some heat and it wouldn’t get above 180, then my fan kicked on and cooled it right down to around 160 (which was the lower threshold of the fan) I took it for a drive down the freeway, flogging it a bit and it never got above 176, sitting in traffic, abusing it, I couldn’t get it to run warm. Having an engine running somewhat cool is a good thing, but as you may know, engines are most efficient when they are running around 190-195 degrees, so ended up adjusting my fan and water pump map so it could get up to temperature before the fan kicked on. It still takes quite a while to get warmed up, but I am happy where it sits for now. I will take it to the track this summer and give you guys an update on my findings! Thanks for taking the time to read all of this; hopefully this will help you decide on a replacement for your radiator. Mishimoto has a huge selection of radiators and they list all of the dimensions on their site which helps a lot!
Thanks
Corby