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Discussion Starter #1
Hey all,

I did a search and found nothing on the matter of a coolant system conversion for the 998.

My 998 is unbearable to ride 90% of the time with temps between 225 and 250 and i'm just tired of it. It has a fully built motor so the temps are a bit above average from the standard 998's i've owned.

So I started looking at radiator alternatives and I refuse to pay 2k for an oversized RS setup. So I turned to other alternatives I had and have found that my 1198's radiator and coolant plumping appears to work on the 998 with the addition of some plastic elbows for the plumbing.

I'm hoping with the increased radiator capacity of the 1198 and the more efficient fans, the 998 will maintain a temp between 180 and 210. Also, with this setup there is no need for the troublesome coolant reservoir as the radiator has a cap and i'll replace the 998's overflow reservoir with the standard overflow from the 1198.

I will begin mocking up a spare 1198 radiator I have. If everything lines up with the fairings on, i'll solder on the bottom mounting tab to work with the 998's frame.

Does anyone have any feedback to offer on this matter or past experience?
 

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I assume most of the issues are related to low-speed riding and not flat-out highway stuff.

If thats the case, there are fan switches available which turn them on MUCH earlier. That will help with the slow speed stuff and should dramatically keep the engine cooler.

www.eurocorsa.com - EVOLUZIONEDUCATI748916996LOWTEMPFANSWITCHKIT

The other thing you can do is change the coolant. Standard glycol coolant doesn't work very well at keeping temperatures low. Non-glycol coolants like Engine Ice and Water Wetter both work fantastic at keeping the temps lower. In fact, the pre-mix jug of Engine Ice runs about 10% lower on temps across the board.

So the mix of the fan switch AND alternative coolant, should help substantially. Changing radiators is a bit tricky because the 1198 engine is shorter then the 998 engine. As a consequence, the radiator can be larger on the 1198 since the head is behind it. I believe if you put a 1198 radiator on an 998, it will stick forward. This may cause rubbing when the front tire is compressed all the way under heavy breaking.

Ohh and by the way, my 848 had the 1198 radiators and it ran around 220F all the time.
 

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Discussion Starter #3
Hey Tuned,

Thanks for the advise, I was a bit worried about the head clearance on the 998 but didn't think as far too the front tire compressing into it, thanks for pointing that out. I run engine ice in the bike, it helps out a little but nothing dramatic. I would be happy with a consistent temp around 220 as mine is normally closer to 250 in low speed riding as you mentioned. High speed riding, the temps maintains at 220.

I'm against the electric fan switches as the last time I tried that fix was when evoluzion was around. My bike would be dead by the end of the ride with no power to start. Im not sure if it was a charging issue with the bike or just the fans demanding too much voltage.
 

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Just a thought;
Thermostat ok? Pump ok as in the impeller is loose on the shaft?

The temp gauges are notoriously in error and as I assume it's not boiling over are you sure it's running that hot?
Get a decent infrared thermometer and look at the flat black hoses for a reading. (IR works best with black surfaces. The lighter the color of the reflecting surface the lower the reading will be)
 

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Discussion Starter #5 (Edited)
Hey Slower,

Thermostat and impeller are in good working order. I've also gone through two different temp gauges, as I thought it was an error as well but, they're both consistent with each other. I also replaced the coolant housing where the temp fan sensor sits but same result. The motor is fully built and does run hotter than a stock 998, which is to be expected to a certain degree but, it's just a bit much. It also has a 60mm exhaust which adds to the uncomfortable hot rides also.

This is why I think a larger capacity system would be better. I am also considering trying a 999 radiator and soldering mounting tabs to fit the 998. From my research the 999 radiator has increased capacity and "should" work without clearance issues.

All in all, the 998's cooling system in total, including it's fans barely keeps a stock 998 cool, nevermind a modified one.
 

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I'm against the electric fan switches as the last time I tried that fix was when evoluzion was around. My bike would be dead by the end of the ride with no power to start. Im not sure if it was a charging issue with the bike or just the fans demanding too much voltage.
Thats simply due to a bad battery or regulator, for sure not the fans at all. In fact, the fans should draw less then the headlights.

But yea, you can try the radiator, I just don't think the few extra mm of cooling will make any significant difference.
 

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Discussion Starter #7
If thats the case, I will try the fan switch kit again and report back with results. I just remember when I did this mod, my fans were on ALL the time. Stay tuned.
 

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Try Bellissimoto they have oversized radiators. Over 3 grand but similar to my Fubar one and it never gets hot on my 998 with R Cams and 54mm exhuast even on the track.
 

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Discussion Starter #11
Westernova, 3k for a radiator is crazy money to me.I understand the need for the application but I mean damn!
 

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Dang, testastretta! WOOPS! Sorry, totally forgot about that.

Well, I guess ya gotta go for the radiator and hope for the best?
 

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A big problem is that the 998 fairing vents that exhaust cooling air are smaller than on earlier 916 and 996 models.

One thing that's often overlooked on Ducati superbikes is that both oil and coolant radiator fin damage occurs from road debris. Without protection, the fins get bent over, air flow through the radiator is reduced, so coolant and oil temperatures rise over time. You need to carefully straighten the bent fins and use a protective screen to prevent future damage.

Also, there are radiator flush products that are effective in removing rust and scale from internal surfaces thereby increasing the heat transfer effectiveness.

The best cooling liquid on the planet is water — so using water plus a coolant additive such as Water Wetter or Motul MoCool to promote better heat transfer will give you the lowest operating temperatures. Obviously, if you need freeze protection a glycol/water mix is needed.

You can always reduce operating temperatures by increasing the percentage of water in any water/glycol mixture. Plain distilled water has twice the heat transfer (cooling) capability compared to glycol-based coolant mixes, but shouldn't be used alone as a coolant since it lacks corrosion inhibitors and water pump seal lubricating properties.

WaterWetter or MoCool is often used because it reduces the surface tension of water (the property that makes it bead-up) thereby improving further water's superior heat transfer ability while also adding the necessary lubricants and corrosion inhibitors. It can also be added to a water/glycol mix.

Most important, these additives will reduce coolant temperatures across-the-board under all operating conditions. It's big advantage is use in modified engines having increased heat loads, and under high-load, high-rpm track conditions.

Typical 998 Operating Temperatures on a 90°F Day for a Stock Engine

200°F @speed with WaterWetter/water
210°F @speed with 50/50 glycol/water
220°F @traffic stop with WaterWetter/water
250°F @traffic stop with 50/50 glycol/water

Propylene glycol used in Engine Ice has better heat transfer efficiency than ethylene glycol.

You should note however, that even though the two coolants have similar specific heats, boiling points and specific gravity (alone or mixed with water), that propylene glycol's viscosity is significantly (1.4 times) higher, particularly when cold (2.5 times). This means in a Ducati system — designed and sized for an ethylene glycol/water coolant — that a propylene glycol/water mixture will circulate slower and with higher pumping losses and stresses on the pump impeller.
 

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I had a same issue here . I flushed the radiator , using engine ice + evo . temp switch + I replaced the right side fan to a 998R aluminum blade fan . Way better than before . In traffic never above 210 F highway 180 F.
The R fan is more efficient than original plastic sh.t.
 

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Oh , I do not think the low temp switch does anything , since its goes on by ECU I am still thinking to add a manual switch but I could not figure out where should I connect the wires .
I di ones but as soon as I turned on it never turned off until I stopped the engine with the key . So I removed it .
 

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Discussion Starter #16
Thanks Shazzam and Racka for the detailed advise. I wish I could run distilled water mixed with water wetter but I live in New England, and I have to worry about freezing every year. I suppose the best way to go would be to just run distilled water/ water wetter in the summer and when the fall comes with cooler temps, swap to a glycol mix.

I never really looked at the condition of the radiator fins, but that is a very good point regarding the air flow being obstructed by bent fins. I will check this out over the winter for sure.

Racka, where did you get the 998R fan? After all the advise, I am leaning away from the radiator swap and putting more thought into upgrading the fans to a better design. I wonder if the 848/1x98 fans will mount up with some light fabbing.
 

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I do the same thing with water wetter and distilled water before my first track day of the year which is typically early spring (April) and then switch it back to glycol after my last track day of the year (October). I have a heated garage in my building but I like to ride in the winter when the weather allows it and certainly welcome higher temps when it's cold out. I used to use the engine casing on my monster as a glove warmer while riding! Don't forget to swap the overflow tank when you do the coolant swap.

Regarding the radiator fins: I used to work in hvac design and always carried a fin straightening tool/ comb with me when I went into the field. You can pick them up at Grainger, McMaster-Carr or other stores for $10 or so and they come with different size tips for different sized FPI (fins per inch)
 

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I have been riding around Daytona the last couple of days in pretty heavy stop and go. I just did a cooling system upgrade with the Speedymoto water pump cover, Evoluzione fan switch, and Motul Motocool. I have not gotten above 210 in any situation. It is still roasting my legs when stopped too long in traffic, but I think that is mostly the exhaust. I will always have to deal with some traffic and I feel like I am finally getting closer to making the bike liveable. The temps have been in the low 80s here. As soon as I get up to speed for a minute or two she drops back around 180.
 
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