Plagued with overheating problem By skysoldier173d (Read 5,848 times)

[skysoldier173d]

Can you tell me which temp sensor this unit is that is located on the lower left of the radiator? On the engine there is a sensor tapped in just to the left of the intake manifold. If that is the temp sensor, what would this one on the bottom of the radiator be used for?
Thanks,
Ern

[zugzug]

The one on the bottom of the radiator contols the fan. The one up by the manifold goes to the temp gauge on the dashboard.

[skysoldier173d]

Thanks zug, If you will refer to the pic of the small size radiator it's no small wonder why so many Road Runner Racer Linhai 250 Scoot owners are all having overheat problems. The fan may appear large but look closer and you will see that it isn't much larger than the beep-horn sitting just to the left of the fan. Problem seems to be SMALL,SMALL radiator.
I'm contemplating various mounting scenarios of adding in 2 additional 4" fans. Wish me luck,
Ern

[jhbietz]

I your considering adding an additional radiator you can check out my thread under 250's. I'm converting a tank 150 to a 250 so I have to build a complete cooling system. I used a honda helix radiator and mounted it to the frame behind the front wheel.

[Cruiser]

The typical 250cc scoot cooling system holds a little over a quart. If your system holds about the same, then the radiator is about an average size. The first thing I would do is increase the amount of air going through the original radiator. The fan guard grill is very restrictive looking. I would remove it or most of it. Moving the the fan to the left or right and doing the Dr. JR fan add on would probably help a lot. The area looks very tight and a larger radiator might not fit there. Even if a larger radiator will fit, the air flow in and out has to be improved, IMHO.

[speedracer]

skysoldier173d

You had mentioned that your fan sucks air in when it's on. I checked my fan and it does the same. I have not had any over heating problems except after changing out the antifreeze. Then after about burping it 3 times it has been fine since. My fan kicks in when the gauge goes just above the middle marker. Perhaps the fan is running the right way as the engine is not even close to the radiator unlike a car where is apart of the engine. My .02

[skysoldier173d]

Thanks for your input. Originally my fan was blowing out towards the front of the Scoot. Later I reversed the dc wiring and it blew correctly (blowing over the radiator front to rear). Since then I removed that fan which was high current and low air velocity. I replaced it with twin 4.5in 850 cfm fans mtd side-by-side running constantly thru an off/on switch should I decide to shut down the fans. It is the best cooling I have had so far but sure enough after I run about 5-6 miles the overheat condition returns with the needle all the way to the right of the "H" mark on the temp gauge. It's loaded up with 50/50 Dexcool antifreeze and perhaps I should retry the burping routines but previously, I burped the eng so much that I thought I would be soon wearing out the drain plug at the water pump. thanks again, ern

[skysoldier173d]

I would like an expert opinion from someone regarding differences noted in my factory orig water pump and a replacement water pump. The impeller diameter of my orig impeller was perhaps slightly less than an inch. Originally when I started having overheating probs which was right out of the crate I called my dealer and he sent me a replacement water pump. The repl. pump however had an impeller 1.47 inch dia. which is a substantially larger impeller than the factory original. Could someone in the technician chain either from factory or US distributors realize that the orig Linhai 257cc eng had an impeller that was too small and/or too low of pumping volume. Would it be wise to change over to the water pump with the larger impeller? And lastly, what is the trick to jerking out the factory supplied water pump to free it for removal. Previously I tried wiggling and shaking once all the bolts were off but it didn't seem to want to budge. Could I try prying it out? I was hesitant because of the risk of damaging any of the die cast or pig iron metal. I would be grateful for any good recommendations. Thanks in Advance, Ernie

[Cruiser]

Here's the fan I used to replace my original. It's rated at 1100 cfm and it cost $24.99. It uses about half the power of the original.

www.siliconeintakes.com/product_info.php?cPath=15&products_id=1024&osCsid=2bf68d71e32fe413cbb745cbd96ddb55