Pressure won't go away

[tn220]

I have a 97 220. For the last few rides it started puking antifreeze. I know some of the 220's do this but the odd thing is mine didn't used to do it. It will lose a 1/4 of the radiator a ride. To make this more odd, my radiator holds pressure long after a ride, like days later I can remove the cap and you can hear a good amount of pressure release. I bought a new cap but it still does it. Any ideas?

 

[est142]

That's a good one. I have the same year,same bike. I never lose coolant. The cooling system goes from 0 psi stone cold to a maximum of whatever the relief pressure of the radiator cap is. 12 psi I think, but I am not positive. I do not understand how it could maintain pressure after the engine cools off either. Maybe something is clogged. I am sure you did the obvious like clean and straighten all the radiator fins, and bleed the cylinder head of air. If the radiator cap is new, and coolant level is good, you are either not circulating or not dissipating heat. Maybe bad water pump impeller or clogged radiator core? Sorry for no exact solution...just trying to think it thru with ya.

 

[tn220]

It's got me fooled, I'm hoping for some direction before I start tearing apart and guessing. It's sitting in the basement waiting on a new brake caliper now so I'm hoping for a cheap fix.

 

[TimberPig]

The symptoms you are describing sound like your head gasket is letting combustion pressure leak past it and pressurizing the cooling system, but not letting it bleed back when the engine cools. Try popping the rad cap off, start the bike and look for bubbles in the coolant. If there are bubbles, order a head gasket, pull the head and check it for trueness. If the head needs truing up, it can normally be cleaned up with sandpaper mounted on a hard, flat surface that is perfectly straight, like a thick steel plate, or a thick piece of glass. The top gasket surface of the cylinder could need truing too.

 

[tn220]

The guys at the local shop all said "don't worry about it, it's normal" but in the back of my mind I know it's not or it would have always done it. It wouldn't hurt to do the top end on it anyway. It still runs strong so the guys say "let it go until you know it needs it" but from your post it might be a good time to pull the jug and let a machine shop check everything.

 

[ridejunky]

I think TimberPig is kinda on the right track, it could be possible that your cooling system is experiencing the canning effect. Forcing coolant out when hot, but after cooling, it creates a vacuum so to speak, Listen carefully when opening is it hissing or sucking? If you are loosing coolant, and the bike is fully cooled down, how can it possibly have more pressure than when you started?

 

[TimberPig]

The guys at the local shop all said "don't worry about it, it's normal" but in the back of my mind I know it's not or it would have always done it. It wouldn't hurt to do the top end on it anyway. It still runs strong so the guys say "let it go until you know it needs it" but from your post it might be a good time to pull the jug and let a machine shop check everything.

I'd recommend you don't listen to the guys at the shop. You stand to damage your engine if yuo simply ignore it and hope it goes away. This isn't normal, and it needs to be fixed, not ignored.

 

[tn220]

I haven't ridden much lately so it would be hard to say if it is hissing or sucking, I won't be able to ride it until I get the break caliper back on but I might try running it in place just to see about the bubbles and which sound I get when I remove the cap. Just a thought, does it matter that much about running distilled water in the radiator? I didn't have any the other day and I just used tap water to mix/w the antifreeze to get it going again. Thanks for the help everyone..

 

[TimberPig]

Tap water contains minerals dissolved in it that can corrode the internal passages of your aluminum engine. This can result in deposits forming in the system and potentially clogging. It is better and safer to only use distilled or deionized water in your bike.

 

[motodr9]

I vote head gasket also, and I wouldn't wait like your "shop" told you. Losing 25% of your coolant after a ride is not normal. If left unattended, a leaky head gasket can damage your cylinder.

 

[tn220]

Well, finally had a chance to get the brakes back together tonight and took the bike out of the basement so I could fill the radiator and start it to see what it would do without the cap on. I started it and let it run for a few min. and there were all kinds of bubbles on top of the coolant. If I idled up maybe 1/4 throttle it would put quit a bit out on the ground and get really bubbly. I could see the watter circulating quickly so that seems good but from what you guys say about the bubbles it looks like it's time for a head gasket, what do you think?

 

[TimberPig]

Yup, your head gasket is shot. Time to pull the head and replace the gasket.