3rd Gen (1993) Coolant Resevoir Question

Good Morning,

I have a 1993 VFR750F.

• When the bike is cold (i.e. sitting all night in my parking spot) the Coolant Resevoir is empty
• When the bike is hot (i.e. been riding it for an hour) the Coolant Resevoir is at the low mark

What should the coolant level be when the bike is cold?
I am wondering if this is normal.
If not, could this be a sign that I am burning coolant? I am not sure what sort of things to check as there is not a single performance problem with the bike. It starts and runs great.

Any information/advice is greatly appreciated.

Derec

 

The plastic tank acts as a reservoir for the coolant. As the coolant in the radiator heats up and expands it takes up more room than there is in the radiators so it overflows into the reservoir tank. As it cools down it draws the coolant from the tank back into the radiators. This helps to keep the radiators at full capacity and prevents the coolant from spilling out. As long as you are not burning or leaking coolant I wouldn't worry about it. If the bike is producing a unusually sweet exhaust smell you should check to make sure coolant is not leaking into the oil through the head gasket. This usually can be determined by changing your oil and checking to see if it has a milky or cloudy light brown color.


Regards,
Rollin

 

When the bike is cold, the coolant needs to be between the Low and High mark in the reservoir bottle.

Low coolant can cause all sorts of heating problems.

 

^^ Yes. When the bike is cold, it should be between the low and high mark. So when topping, you should top all the way up to the high mark. The low mark just indicates the minimum that should be there before refilling.

The lines on the coolant tank ARE NOT "hot" and "cold" marks, like they are on some vehicles. They are both "cold" marks. In fact, when your radiator is filled properly, the reservoir level shouldn't noticeably change whether hot or cold on this bike. Any noticeable fluctuation indicates some air in the system.

Your coolant is definitely low. When the captive air in the radiator heats up and expands, some of your fluid is getting pushed back into the reservoir. Once the fluid level left in the radiator gets low enough to allow it to boil, you will rapidly lose all your fluid and melt your gaskets. So top it immediately.

You don't burn coolant. You leak coolant. If you had a leak, you most likely wouldn't be seeing the reservoir back up when warm.. it would be exiting the radiator through the leak. So in all probability, you just need to add some coolant. It's normal to lose a bit of fluid over the course of several years, and who knows the last time anyone checked it on your bike.

Once filled to the high mark, warm up the engine and let it cool, again. When warm, the entire reservoir might back up and even possibly spill a little. But when it cools, it will suck some coolant back into the radiator to replace the air. So you might have to do this a few times: topping>cycling.

 

sometimes people think they are filling their cooling system by filling up the reservoir: NOT CORRECT.

Since the reservoir is only an overflow, filling and checking the cooling system should be done under the radiatior cap only.

 

^^ um, yeah. Do what he said.

 

UPDATE!!!
Last night I topped up my Coolant via the Reservoir.

• Is this bad to do?
• What does this do if it does not put Coolant back into the system?
• Is my Coolant level going to continue to be low?

Now...when the Bike is cold the Coolant level in the Reservoir is at the Low mark and when the Bike is hot the Coolant level in the Resevoir is at the high mark.

• Is this bad?
• What does this indicate?
• Is it bad that it fluctuates? (...I am under the impression that this is normal...)
• Is this a sign that I have air in my system that needs to be removed somehow?
• I thought I read somewhere that as the Coolant expands into the Reservoir and gets sucked back in (when it gets cold) that it would bleed any air out on its own...is this not true?

Basically I am looking to get an idea of what "normal" is going to be and how to ensure that my Bike is properly topped up with Coolant and is running "normal". Any advise is greatly appreciated.