So I need to replace my radiator. What's in there now is an OEM style (metal top instead of plastic) copper/steel dual core (I think) rad. I was looking at a the Fluidyne and C&R radiators thinking that it might be a good time to upgrade, but I haven't really found anything in the descriptions that says why they're better than OEM. The description of the Fluidyne on most websites is something to the effect of "impress the judges with this bling." What do you gain with aluminum rads and is there any reason to buy one over an OEM style replacement for an H4 car? Keep in mind that my car is already min weight, so that's not really a consideration. TIA

- Scott

 

well, at least in regard to us miata people.....

the OEM radiator is too thin, the Koyo that most people use in place of the factory is 3x as thick as the one that comes out. that's a big cooling advantage. another one is that the aluminum koyo has much bigger tanks than the oem and thus holds more water. yet another cooling advantage. the radiator itself is lighter than the factory one, but fill it up with water and it's actually heavier. well, for us at least.

 

the best thing to do is determine if you car needs the extra capacity. If your water temp gauge reads high, then you may need the larger radiator. If not, OEM may be fine. I don't have a gauge installed and I just figured better be safe than sorry.

 

logic would indicate that if you're having cooling issues with a stock radiator then it would make sense to upgrade, if not you're just spending extra money.

I'm sure a larger more efficient radiator would provide better cooling and better cooling = longer lasting engine, but is there a real need for better cooling if the stock setup is handling the job?

 

The difference between an all-brass and an aluminum constructed radiator should be minimal as long as comparing the same # cores and same size, etc.

If you go to a decent radiator shop, they can order/build a stock size radiator with an extra core (thicker) over OEM to give the extra capacity for cooling a race car.

I did this several years back for my ITC CRX and have a nice, OEM style brass radiator with two cores instead of the stock one and it was pretty cheap at the time. The added benefit with extra cores is that if you have a small leak, a shop can close off the leaking tube to keep from buying a new rad.

Just make sure to steer clear of the radiators with the plastic end caps...

 

another benefit....

piece of mind.

i like knowing that i have a radiator originally designed for V8 F-bodies. i figure that should be plenty of cooling during the insanely hot july/august months here in kansas.

after having so many overheating problems, i just went nutso and bought the biggest radiator possible, all new hoses, bypassed heater core, new thermostat, blocked off everywhere air could go other than through the radiator, and dumped in water wetter.

it's nice to not have to worry about it anymore.

 

Thanks guys. I think that a dual core OEM style brass radiator would be enough to keep the car cool considering that my teammate runs one in his H4 CRX and was keeping water temp to around 210* in May with 120* air temp at the track (Phoenix is hot ). This car has had cooling problems since I got it, but I think the radiator has a blockage or something. The previous owner didn't know what was wrong with it, but said it didn't always run that hot. I was seeing temps around 240-250* with about 100* air temp in Sept with this radiator, but I think it was only using 1/2 of the radiator or something. The side that the fan is on was cold to the touch and turning the fan on while sitting still does nothing to reduce temp. The temp slowly climbs even at idle and it will eventually overheat. The entire motor was replaced (for other reasons) and it does the same thing, so I'm thinking the radiator is the only piece of the puzzle that could be the problem. Anyone else have thoughts?

 

210 isn't bad at all, but were you running in the draft?

running in nothing but hot exhaust fumes can raise your water temps quite significantly.

just something to consider.

 

Aluminum radiators can bend in an impact instead of cracking, giving you a chance to finish the lap, if not the race. Can also be bent back, or welded if more repairs are needed.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by drdisco69 &raquo;</TD></TR><TR><TD CLASS="quote">Aluminum radiators can bend in an impact instead of cracking, giving you a chance to finish the lap, if not the race. Can also be bent back, or welded if more repairs are needed.</TD></TR></TABLE>

isnt that the opposite?

aluminum cracks, steel and copper bends.

aluminum is difficult to weld, steel and copper are easy.

i suppose compared to plastic, aluminum is superior. but all metal radiators are typical.

 

Depends on the type of aluminum used. Since the radiator isn't structural, you can use "softer" alloys.

 

kinda off topic, but are the Koyo OE style/type radiators, the ones for EG civic, are they dual core, metal end caps? I see them at online car parts stores, but i cannot tell from the pic if the black encaps are plastic or metal, and if it is dual core or not.

I know that the EG auto rads are dual core, while mine, a 94 ex coupe 5spd, are single core platic tanks.
thanks in advance.

 

Thermal conductivity.

Aluminum: 170-200
Brass: 160 max.

So the aluminum radiator will have more heat transfer over a given amount of time, so it cools better than brass.

It's also lighter.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by FlyZlow &raquo;</TD></TR><TR><TD CLASS="quote">Thanks guys. I think that a dual core OEM style brass radiator would be enough to keep the car cool considering that my teammate runs one in his H4 CRX and was keeping water temp to around 210* in May with 120* air temp at the track (Phoenix is hot ). This car has had cooling problems since I got it, but I think the radiator has a blockage or something. The previous owner didn't know what was wrong with it, but said it didn't always run that hot. I was seeing temps around 240-250* with about 100* air temp in Sept with this radiator, but I think it was only using 1/2 of the radiator or something. The side that the fan is on was cold to the touch and turning the fan on while sitting still does nothing to reduce temp. The temp slowly climbs even at idle and it will eventually overheat. The entire motor was replaced (for other reasons) and it does the same thing, so I'm thinking the radiator is the only piece of the puzzle that could be the problem. Anyone else have thoughts?</TD></TR></TABLE>

Have you pressure tested your cooling system to make sure you don't have a leak? Thermostat okay?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Johnny Mac &raquo;</TD></TR><TR><TD CLASS="quote">Have you pressure tested your cooling system to make sure you don't have a leak? Thermostat okay?</TD></TR></TABLE>

The previous owner had removed the thermostat housing altogether. I'm guessing it was an attempt to fix the problem. I put one back on (thanks Edo!) with a brand new 170* motorad thermostat. I haven't done a pressure test, but I pulled the rad tonight and I'm taking it to a shop tomorrow for an inspection and routing. It seemed like the system was holding water ok. There didn't appear to be any leaks, but I guess you never know. It wasn't dripping and the rad always looks full. I'm thinking about replacing the rad hoses as they look a little old/weak, but I don't think that the hoses would have anything to do with a problem like this would they?

I'm really having trouble finding a suitable replacement radiator in town. Everything is either single core or has plastic caps. I'm hoping that routing the current rad works good enough to run it this weekend. That would give me more time to find a good replacement.

 

A lot of OEM radiators use plastic end tanks.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by FlyZlow &raquo;</TD></TR><TR><TD CLASS="quote">

I'm thinking about replacing the rad hoses as they look a little old/weak, but I don't think that the hoses would have anything to do with a problem like this would they?

</TD></TR></TABLE>

Actually, the old rad hoses could be a problem. If a hose has a very small perforation the cooling system will not operate under pressure and you could get overheating very easily - since the boiling point of coolant will be significantly reduced. Sometimes the hole in the system is hard to find, such as behind the hose clamps.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by TeamSlowdotOrg &raquo;</TD></TR><TR><TD CLASS="quote">A lot of OEM radiators use plastic end tanks.

</TD></TR></TABLE>

youre right.

i guess i read disco's comments out of context. sorry man.

 

Toss that Motorad thermostat in the trash! Put a stock honda thermo back in and see(if you've never tried).
I never had any luck with those , except for price they gave me all sorts of headaches with fluctuating temps. Some worked fine some didn't...a true hassle.

You should only need a dual core from a 90+ teg which will drop into tht rex, which is probaly what you already have in there but it sounds like you could possibly have a bad rad.


Modified by essex at 6:12 AM 11/30/2005

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by GSpeedR &raquo;</TD></TR><TR><TD CLASS="quote">Thermal conductivity.

Aluminum: 170-200
Brass: 160 max.

So the aluminum radiator will have more heat transfer over a given amount of time, so it cools better than brass.

It's also lighter. </TD></TR></TABLE>
yep.
Aluminum transfers heat much quicker. Try welding aluminum sometime. Its amazing how fast it goes from glowing hot to able to be picked up by hand.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by essex &raquo;</TD></TR><TR><TD CLASS="quote">You should only need a dual core from a 90+ teg which will drop into tht rex, which is probaly what you already have in there but it sounds like you could possibly have a bad rad.
</TD></TR></TABLE>

To clarify, the radiator he's talking about is in his H4 DA Teg LS, not the H4 CRX. I am the teammate with the CRX, and though I was cursed with my own overheating issues last weekend, I think we've got a handle on it.

- Jon

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Tyson &raquo;</TD></TR><TR><TD CLASS="quote">i guess i read disco's comments out of context. sorry man.</TD></TR></TABLE>

Hey, no problem. I was thinking of that, and the fact that even if it has metal end tanks, you might not be able to weld them to the core if you had to make repairs, as they might be different materials.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by GSpeedR &raquo;</TD></TR><TR><TD CLASS="quote">Thermal conductivity.

Aluminum: 170-200
Brass: 160 max.

So the aluminum radiator will have more heat transfer over a given amount of time, so it cools better than brass.

It's also lighter. </TD></TR></TABLE>

Aluminum is around 235 W/M*K, and brass is around 120 W/M*K, but aren't most radiators made of copper? Copper has a thermal conductivity of around 385 W/M*K, making it almost twice as efficient as aluminum. I thought the cores were copper, not brass, but I may be mistaken.

 

The other issue that could be causing the overheating is buildup/clogging of the radiator tubes internally. If you ever look in a lot of older rads- check out all the junk that is usually found inside them. This flow restriction will greatly reduce the cooling ability of a radiator.

I would also use a new OEM thermostat since just removing a thermostat will allow too much coolant flow through the system and not cool properly.

 

something to consider is that if you have an aluminum rad you can't ghetto fix it at the track as easily with ordinary solder