I've been going through my project 2006 600 that the Missus scored on Craigslist for $900 a couple of months ago.
Here's the question: the parts fiche (Partzilla) shows a wide heat shield mounted to the top of the radiator and hanging down to the rear a bit. Yet I can't find any mention or illustration of this in the factory service manual and while the bike was a mess when we trailered it home, the seller did give a tub of parts that mostly completed the bike- only a few fasteners and things like that were missing.
Did the '06 600 have a shield normally or is that a ghost on the fiche?

I never noticed it, but here it is on my K6 750. I looks like it directs hot radiator air down and away from the top of the engine and going under the fuel tank.

It's more of an air dam to force air through the radiator instead of around it. IMHO, if you don't have one on your bike, buy it and install it.

Given the overheating stuff already going on, I will take any advantage I can get.
I've already ordered one. Now, with 20 degree temperatures forecast all week, I won't really be able to challenge the cooling system without sliding into a ditch. More than 25 degrees below "normal"!

K5/K6 1000 has a similar but smaller part. It's #3 here. It was omitted as part of the frame brace recall. The bikes run slightly hotter without it as it allows air to bypass the radiator but this isn't an issue unless you live in very hot areas like Palm Springs. Also the top of the engine gets dirty quicker. Yours might be more important.

In the K5/K6 1000 manual it's part of the Cowling Installation diagram, where it's referred to as the front under cowling. But I don't see it in the equivalent K6 600 diagram. Go figure.

So here's the fiche picture. I'll be darned but I can't see from the outside how this shield attaches.
I see the two clips on the top corners of the shield but it's not obvious where they go.
I may not have time to get things taken apart for a bit to get a better look.
I did test ride the bike yesterday and after a good run simulated some low speed running in a forest preserve and sure enough, overheated again, red light and all. And the ambient temperature was only 41deg F. Getting moving again did reduce the reading.
The fan is coming on properly. The coolant comes out clean and is almost brand new Honda HP2. The tech at the local Suzuki shop tells me the radiator is hopelessly clogged in the area of the cooling fan, common on these bikes. He recommended a used one from a local shop that does parting. Instead, I got irritated enough to order an aftermarket radiator from RCS Racing in Florida- says it's made there, and that it gives a 35-40% increase in cooling capacity. We shall see.
I've also been told to go over to Engine Ice for better cooling, but the bike is probably going to be stored in an unheated garage which could conceivably go below the Engine Ice's claimed freeze protection point during our (already cold) winter. I may try that in spring.

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I took a look at my bike. The studs on the bottom of the part slide into tabs that are part of the cylinder head casting. It looks like the left and right attachments are attached to the inside of the fairings.

Ah, thank you. I hope to dive in there in a few days.

You can see the studs on the top rear of the under inner cowls that the shield clips onto here. One person who looked into this on his 1000 reported that at speed the wind pressure would cause the under inner cowls to spread if they weren't clipped on, which would let air bypass the radiator instead of flowing through it.

I'd suggest that you stay with EG coolants. The key is to find one that you like, fully purge the bike of whatever is in there (drain, then flush out with a hose, fill with distilled water, run a bit, and drain again), and use nothing but that coolant from then on. I like Zerex G-05 but suit yourself. Mixing different coolants is a good way to get corrosion or possibly clogging.

I question the "hopelessly clogged in the area of the cooling fan". If you are changing the rad anyway just for the hell of it pull the old one off and get some good foaming coil cleaner. Spray it on and let it work. Flush the rad through with water from the back...pushing the dirt out the way it came in. Gently, not more than you can spray holding your thumb over the end. Doing this a few times with a little patience should clear it up. I have cleared HVAC coils that had 15 years of heavy use and no cleaning. You may have to let it soak and tackle it again the next day.

Oh, make sure you get an aluminum compatible foam...most are but check and a soft brush with the fins. I had a jack ass power wash a coil once...flattened it completely. Another guy scrubbed in circles also not good. Don't think you are an idiot...just have to say it based on past experience.

Yeah, Tinsnips, I was skeptical of the clogged area diagnosis but two things tipped me that way- one, the guy has worked on thousands more GSXRs than I ever will and wasn't trying to sell me anything- he sent me to another shop!; and two, the way it overheats does suggest the possibility.
When we bought this bike off of Craigslist (for $900!) it had a blown freeze plug and the cooling and lubrication systems were filled with a white goo. I took a chance based on the low price, and honestly, the motor runs fine now and sounds pretty sweet.
After many oil and coolant changes, at least five apiece, things are starting to seem okay.
Pricey, but now the oil looks positively lovely after about 450+ miles on this latest filling.
The coolant comes out looking pristine now, too- I had a good look when I dumped the HP2 to change the thermostat.
I'm down to the parts-changing diagnosis method. All I have left is the water pump and a slight chance of a blown head gasket (but there's no other symptoms of that.)
Still, if you search-engine "GSXR overheating" you will get upwards of several zillion hits. I don't feel alone.
Ironically, parked next to the GSXR is Her Highness' other Suzuki, an SV650S. Talk about a mild-mannered, inoffensive, don't-know-it's-there Golden Retriever of a bike. That thing wouldn't overheat if you dropped it in a brazing furnace. If it has teeth, I've never seen them. Never seen it bite. What an outstanding newer rider's bike.

"blown freeze plug...white goo" I'm guessing a plug in the head because I'm thinking that the crankcase plugs are screwed in. In any event that sounds like frozen coolant because the previous owner didn't have proper coolant in it. Improper coolant, in turn, suggests that there was corrosion and the white goo may be a mix of oil + water + corrosion deposits. I hope that you've checked your oil cooler because it could easily be gunked up too.

Yes, the previous owner prepped it for a track day with water then left it in his father's garden shed for a couple of years. The three plugs in the head had popped. He had reinstalled them but the center one evidently blew again on him. It was loose in the cam cavity when I opened it up.
He also had some ether glycol or something like that to be used as a flush, and I ran a dose of that through early in my possession, among plain water flushes and multiple coolant changes.
I will be digging into it in a few days when the new radiator gets here and will take a look at the oil cooler too.

In my limited experience with oil cooler intercoolers, they clog more easily than the radiator. He might have used water wetter, which has an anti-corrosion additive. But I'm suspicious of leaving it in the bike for long periods. Water is dangerous stuff in a cooling system. I've heard of a track bike's water pump freezing up while it was being transported home (caused the drive shaft from the oil pump to snap when it was started).

P.S. I hope it's obvious that those plugs must not come out while the engine is running, i.e. they must be well installed. Unfortunately I don't know much about reinstallation. Maybe someone else here does.

I actually reinstalled the loose plug. It's stayed put for at least 500 miles, so I'm starting to think it will be okay.
Freeze plugs are really kind of crude. You just drive them in squarely. In my old days of four-wheelers and work trucks, I'd messed with them a little.
In this case, I'm also convinced the water pump's doing allright. The previous owner said he used water, which I took to be just that, and not water wetter or something like that.
What provokes the overheating sequence is longer trips and higher revs. I can donk around town fine for a half-hour below 8000rpm and nothing happens. Do ten miles on the interstate then dive into regular traffic, and the readout starts to climb.
That's about the only pattern I can see, but it still seems erratic.

I gather that you've bitten the bullet and bought a heavy duty radiator. But an infrared temperature gun should have identified cold/clogged tubes in the original radiator (or maybe just by touching it). Also I'm thinking that it ought to be possible to work something down through the radiator cap opening and into the various tubes to check for clogging and/or clear obstructions. Nylon wire ties are sold in lengths like 36" and they might be stiff enough to do the job. You'd have to finagle something to cause the tie to turn 90° at the tube of interest.

The previous owner was an idiot if he just used straight water. It's only to be used for flushing purposes and should never be left in the bike.

It should be a simple matter to open up the water pump to see what you have. However I continue to be suspicious of the oil cooler.

Finally note that if it's like my 1000, it will quickly heat up at traffic lights, etc. to the point that the fan comes on. But I'd expect it to run cool, just somewhat above the thermostat temperature, under all highway conditions.

Yeah, I just went with the radiator. It seemed the easy thing to do after a couple of stabs at clearing the thing out.
I don't mind the temp climbing in traffic, of which we have a lot in these parts. But the red overheat light going on, that I do mind.
Here, just for reference, is a pic of what I saw when I first opened it up. The loose freeze plug is the left arrow and the hole it goes into is the right one.

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Yes, the red overheat light is way too hot. I made a lighted switch with connector that plugs in place of the fan relay for use when running in the garage for an extended period. Without it the temperature will run up to 221 °F, where the fan turns on. With the switch installed and turned on, the temperature will sit at about 175 °F. The point of all this is that the cooling system plus fan should have no problem keeping the temperature under control. Unless your fan isn't coming on, I don't see why you should be running so hot. Your fan is a ten blade Panasonic while mine is a nine blade Denso. But I'd expect them to behave similarly.

The fan comes on properly at 221deg. It simply can't hold the temperature at standstill. This leads to some boiling-out apparently, but the coolant level is proper before the overheat.
That lends credence to the clogged radiator section theory.
The nice-looking new one arrived today. Now, to find the time to dump the coolant and change it out.

By the way, how were you able to find a larger aftermarket radiator at a reasonable price? I found a RCS Racing in Port Orange FL that sold C&R Racing radiators. But they were just for cars. A Galletto radiator for your bike is almost $2000 on sale here (over $2500 for my K6).

I blush to say EBay.
The ad said RCS Racing although the order return label had a different name, same place in Florida.
The price was $124. The product looks decent enough. I can add a picture for info later.
I hope to install it tomorrow. A test ride might happen, even despite our 40deg forecast.

A few photos of the installation.

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Those upper and lower rubber bushing mounts reek of Suzuki OEM. But I see all the welding on the tanks. Possibly it's a radiator from a different model that is larger (wider?) and they've adapted it to your bike. You should easily be able to tell by comparing it with your OEM radiator. Alternately it could be a clogged radiator that they cut apart, unclogged, and welded back together. In either event, unless the seller knew how to weld well and fast, I'm surprised that it was worth his while. The numerous bent fins make it clear that it's used.

Well, I'm quite sure that this radiator is new, not used. There were absolutely no fastener, tool, or installation marks anywhere. There were no bent fins save possibly one or two slightly touched ones. I probably dinked a few during handling and test fitting before grabbing the photos. There are no large areas of bent fins; what might be seen is a camera illusion which I noticed when I assembled my pictures: those areas that might appear bent are actually straight-through views of the background showing as lighter areas. Be assured I would not accept nor install a new radiator with large areas of smashed fins.
The construction methods are not stock style, but still look to me to be sufficient, and bringing the price down from $800 to $124 is going to bring some differences. So far, those are compromises I'm willing to accept on a "$900" bike.
Yesterday provided just enough weather to gear up and do some riding, 44deg F. and decent enough pavement conditions. I gave it a good run down a deserted refinery road, 90+ in fourth, and then trawled through town to an empty forest preserve to do some slow riding and longer idles. It went well enough. Once the higher rev portion was done, the temps did climb in traffic beyond the usual 185-190 range to around 200, then higher during stationary idling, as it had been doing. The fan (I re-used the stock one) came on right at 220 and the temp slowly came down to the low 200s.
Given the cool ambient, that's not full proof of things being right, but it's better than it was and no red light or plus-235 deg. readings.
Also, no leaks were observed. It would be nice to ride without the smell of glycol coming from the engine bay.
Today is supposed to hit 50 then that will be about it for a while, if not all winter, and the bike will be heading for the back storage so the Missus' car can return to the garage on subfreezing nights.
I sure wish I knew that this was the final solution to this problem, as it's the last known serious one in the resurrection of this shed-find special.

Were the dimensions (width/height/thickness) of the core of your new radiator much different than the OEM?

I apologize for harping on it but have you looked at the oil cooler yet? I concede that it may end up being nothing.

The overall dimensions seemed quite close. I did have to push up a bit during installation what with the "new" heat shield in place, plus it did seem bigger somehow. The unfortunate part is that I didn't get out the tape measure, odd for an old carpenter.
The two top mounting tabs were a bit off. I chose to add a short spacer to the left side tab and will keep an eye on it to see that it stays stable.
I did indeed check the oil cooler by the simple expedient of attaching a hose to the upper nipple and very lightly blowing. Clean coolant came right out the other nipple and there was no sense of obstruction. It was easy to blow through.
I managed another test ride just now- slow work week and 46 deg F- for about 25 miles of mixed stuff.
Cruising at 8000rpm in lower gears did run the number up to around 200-203.
Twice the temp climbed to 220 during breaks and then the fan came on and brought it back down.
After last night's little run, I checked the coolant level in the radiator itself and it was about a half inch below the neck bottom, which seemed in line with the book. The expansion tank had filled a bit from my initial fill and bleed but so far, with fingers quite crossed, so good.

A little bit more about the radiator. Here is the text from the EBay ad:

"Suzuki GSXR 600 and 750 Racing Super Cooling Radiator
2006-2010
SCR Super Cooling Rads
This radiators are heavy duty designed, Flow capacity is increased about 40% than standard radiator ,exceeds OEM specs.
The core of the radiator is welded in vacuum brazing furnace, no epoxy. The tanks are 100% TIG welded
Radiator are Finish by Full Aluminum polished ,Cap is included.
Incorporated in 2009, Exotic Motorsports is dedicated to provide high quality products to motorcycle riders for a fair price. With an intense focus on R&D and Design, EM is constantly developing new products and ideas.EM unlike the majority of our competitors, is an American company. Our customer service, management and shipping facilities are all located in the Sunny Florida, When purchasing our products, safety and performance are of the utmost importance. Our manufacturers overseas are required to follow strict Quality Control Procedures designed and written specifically by EM to ensure all of our products exceed the demands of the American consumer"

Apart from the grammar issues, I found the description persuasive, enough to risk the $124. That price seems low, actually, for what's received if it's as advertised, but we shall see.
Winter has closed in on us early and the GSXR has been sent to storage. It's not likely I'll be able to do much more testing to see how it works out, but so far, so good.