Missing coolant

When I bought my 03 vfr the previous owner had the side cover off. He said he just had the dealer do a coolant replacement and wanted to top it off. It was at the low mark cold.

I said he should leave it in case it's different coolant - not sure if he did anything.

I rode it 4-5 times and then pulled the cover. It was where I saw it last- at low. Again, I'm not sure if he added any.

Fast forward 1,500 miles and the bike is suddenly running progressively hotter.

I check it- the overflow coolant is now just a shot glass full.

I change it- and it runs nice and cool again.

1) where did it go?
2) is there a way to check coolant without removing side cover?

I did find a few hose clamps I rather easily snugged up maybe 2 turns each with a Phillips head screwdriver.

I also let it sit overnight and then opened the oil drain plug a little- no signs of coolant weeping first (under the oil which would float on top).

If its a head gasket would it burn up in the exhaust??

What's the next step(s)?

Bike runs great except for a slight hunting idle. (Fluctuation is less than an eighth of an inch at the tach needle tip)

Thanks!

 

Yes, a leaking HG can burn ofc coolant with no visuble evidence.

However, a small leak anywhere in the system can do the same as it will evaporate on a hot engine. I'd keep an eye on it for a while for signs of dropping level. If it starts dropping again, time to do a cooling system pressure check. Kits can be found at Sears or any parts store for $50 or less.

DO NOT try to preszurize beyond the normal operating pressure of the system (usually 7-13 psi).

 

Most likely a leak. Hunting it down will involve some work, and you'll have to remove the fairings. You can run the motorcycle at idle and look for where it's leaking. Because the water in the coolant evaporates off, you might have to look for build-up of dried coolant. I'd start by checking the drain bolts in case the dealership changed the coolant without changing the washers on the drain bolts.

 

Best advise right there. Too many times they have idiots in the garage OR they are so busy they take shortcuts and\or forget things. Check the drain plug on left side and the one above the oil filter.

 

Though I admit to not being a mechanic, is it possible that there is still some air stuck in the system. Maybe running the bike for a little while with the rad cap off would help to evacuate any remaining air from the cooling system. Had my car in to the dealership a little while ago after I had noticed that coolant kept disappearing from the reservoir tank and they had changed the coolant not long before. They took the car in to the shop while I waited for it (it was already warm from the drive over) and they ran the engine with the rad cap off for about 10 minutes. Since that time, there has been no loss in coolant for over a month now. Dealer said it was likely an air pocket trapped in the system. If there was air trapped in the system somewhere it might account for the higher temps. Just a thought.

 

In Honda VFR engines, a failure in the head gasket is EXTREMELY rare. It is highly unlikely that is your problem. I agree with the other posters that any fluid loss (if indeed there is any) is probably a leak in the "plumbing" somewhere. If that is not the case, then my next guess would be a bad radiator cap.

 

I might bring it to a shop and have it checked for leaks with a pressure test.

Could the water pump "go bad"?

I'd like to reinstall the fairing - any way to keep an eye on coolant level while fairing is on?

I might just pull the fairing after a week of local riding and check the level.

I can keep an eye on temp and if it gets hot ill know to pull the fairing sooner and can chase it down then.

It's just weird and a touch troubling. It's why I stopped buying German cars!

 

Like net4 suggests, with overheating, first check for leaks, then flush the system and refill with fresh coolant, then replace the cap. Caps do, eventually, yield to the inevitable forces of decay and will cause overheating as a result......

 

Would cap issues be evident? (Hardened rubber or cracks)

I really appreciate all the advice!

 

I wouldn't rely on temperature as a guide to coolant level. Coolant temperature is not necessarily related to coolant level. Part of the engine could run dry without a rise in temp.

I know the bike looks terrible without the left side fairing, but until you sort this out, you probably want to keep a watchful eye on the coolant level.

 

I topped it off twice now the day after a ride when cold. Each time the coolant winds up about an inch or less below the lower inner edge of the neck basically level or just below level with the inner top of the big coolant line (not the skinny overflow tube)

The overflow bottle began at the low mark cold- and has progressively risen to the top mark cold.

Ill stop adding coolant then - but could this indicate an obstruction in the system or a leak which permits air in pushing coolant back to the overflow? Or am I overfilling? A bad radiator cap?

 

It's not possible to over-fill as any excess will be forced out of the overflow. If you now continue to loose coolant from the system, most likely cause is a leaky cap.

 

I'm "losing" it from the radiator.
That's what I was referring to in my previous post. It's in quotes because I'm not sure if its really being lost or just getting into the overflow.

Thanks for the help man!

 

Low coolant level tends to cause a high temperature. Coolant level that has fallen below the sensor so that it's covered by air, rather than water, will provide incorrect and inconsistent temp readings. A bad cap causes fluid loss and overheating.

Q.E.D. ??

 

Is the fluid lost into the overflow or out the cap?

 

Out the cap GOES to the overflow...

 

If the cap is bad loss can be out of both. Finding the coolant level consistent in the overflow and 1" below the filler neck means there are NO LEAKS .

 

Yup I'm watching it- thanks all!

 

Now that it's working OK, place a mark on the overflow bottle where the level sits when the bike's cold. If that level drops, it shows leakage somewhere.

 

Already did it yep we are all drinking the green koolaide!