How to replace a thermostat on a 1989 Honda Goldwing? Tempurature gauge gets a little hotter than it should.

Several possibilities:
--the thermostat is only opening partially, not allowing enough coolant to circulate through the system. This is the most likely reason, and the fix is to replace it. Thermostat is cheap -- just make sure to get a new gasket and carefully remove all traces of the old one from the mounting surfaces.
--the cooling system is totally gunked up because it hasn't been changed for years. Buy a bottle (or two) of cooling system flush at an auto part store, add it to the radiator, then follow the instructions. Important for the engine/coolant to get completely hot so the thermostat opens and the chemical circulates throughout the system. Then drain the old stuff while the engine is still hot, but wait until it cools down before replacing w/ water and antifreeze. If you're replacing the thermostat, do this first.
--the radiator is clogged up with corrosion, etc. It can be removed and "boiled" at an auto shop, but often easier and cheaper just to replace it with a new one.
By the way, it sounds like your fan is working properly. When you shut off an engine, the water temperature rises because it's no longer circulating ... so the engine temp sensor turns on the fan briefly to cool it down.

have you replaced the old thermostat ? check also if should bleed the system as well.

The normal temp should be between 195 and 220 degrees. 225 is not bad but does seem a little on the high side. Do you see this temp at idel and then it cools down as you drive or do you see this temp all the time? If you see it all the time after the engine is fully warmed up it may be the gauge is a little off or the trump sensor may be a little off. If you see it at idle and then it cools down while driving than you possible have a bad fan clutch. Another possibility is that you have bunch of debris that has built up in front of the radiator on the outside. Let me know if you have any questions and I'll do my best to answer them. Thank you for using FixYa.com!

I’m happy to assist further over the phone at https://www.6ya.com/expert/jeremy_d728a59f986299fa

The good thing is your fan is working. Now , why do you think it is running hot? Is it boiling over? If not , you just have a gauge that reads high. Most Honda fans do not turn on until the needle is licking the red on the temperature gauge. If you are running hot you might want to try an antifreeze modifier like "ICE". Keep in mind a lot of Honda gauges get more inaccurate with age.

WELL SOME OF THE OLDER CAR RUN A LITTLE HOTTER THAN NEWER CARS THE COOLANT FAN WOULD TURN ON AROUND 180 TO 190 DEGREES.THE OLDER CAR I REMEMBER THE OLDSMOBILE AND PONTIAC ENGINE RUN A LITTLE HOTTER BACK WHEN I OWN ONE.

you must have an air block in the cooling system , presssure the system with water and force out the air

when you had the thermastat replaced the might have put a higher temp one in and that will make it seem like it's running hot you might have to put a lower temp one in

Well, this is a water cooled bike. Few things can cause this:
1.) Low water in radiator.
2.)Dirty blocked clogged radiator fin openings, or clogged inner radiator with rust and sludge.
3.) Electric coolong fan not working- could be temp sensor, fan relay or fan motor itself.
4.) Worn radiator pressure cap.

Honda recommends that the cooling system be topped up with coolant four times as part of the refill process. When the engine is fully cold open the radiator cap and add coolant until full. Run the car until fully warm with heater at maximum. Let it completely cool down. Remove radiator cap and top up with coolant. Repeat this process two more times. This helps purge the air out of the nooks and crannies in the cooling system.

-T

dtramp;

I'm betting on the new thermostat fixing the problem.


Good luck Loringh