Honda Shadow Forums banner

Coolant leak

3K views 29 replies 7 participants last post by  swifty2014 
#1 ·
Hey all,
So I just got my '83 Honda shadow vt750c back on the road, took it for a spin and she started getting pretty hot (rode about 20 mins and was almost in the red) looked down behind my left foot to see what appeared to be a puddle of coolant on the ground, and steam pouring out of the bottom of my bike. Got home, Filled up the coolant (took a fair amount) and went to fill up the reserve tank, and as fast as I could fill the reserve, it was pouring out that same hose. I can't find this hose in the cooling system chapter of my manual, but I will attach a picture, it's the longest of the three hoses. Now I'm pretty new to this, can someone help me make sense of all this?
Thanks in advance!!
 

Attachments

See less See more
1
#2 ·
Have you looked to see if your cooling fan is working? I'm guessin' not. Why are you just getting back on the road? Did it involve the cooling system or draining and refilling coolant. If so, you may not have all the air out of the system.
 
#5 ·
Well, if you didn't properly burp the air out of the system before buttoning it up, you need to do that. Take off the radiator cap and top off the system, start the bike and let it warm a bit. Crack the throttle a couple times to clear the air out, turn off the bike, top off the radiator and install the cap, fill the overflow tank to the proper level, and that should do it. Once you know that's right, take the bike out for a test run and watch the gauge. If it's still overheating, check the cooling fan for proper operation. That's covered in your service manual, btw. You do have a service manual, don't you?
 
#6 ·
Ok, burped the system, went for a 20 minute rip, still got pretty hot. Not quite in the red, but probably closer than it should be. Now that you mention the fan, once I fixed the gasket in the cooling system, I fired it up for a bit to check the leak, and once I turned it off I noticed the sound of the fan, which I had never heard before And haven't heard it since. Finicky wiring perhaps? This is my first bike and I've only had it a couple months so I still have a lot to learn. Anyway, I will consult my manual to test the fan tomorrow evening. Thanks for the help thus far Smilie.
 
#8 ·
I burped mine by using a tall automatic transmission funnel and filled it to above the top level of the radiator cap and get it hot and then let it cool,to draw coolant back in and it will be totally full.

Here is some info about testing the fan and sensor.
Also a photo of the coolant overflow tank showing the overflow hose you were seeing. If you keep filling the bottle it will come out the overflow hose.
 

Attachments

#9 ·
I haven't had any time to test the thermostat or fan over the last couple days. I just went for a quick rip to grab lunch, and when I came out and turned on the ignition I heard the fan engage. Any ideas as to why it would engage so seemingly randomly? I will be testin the thermostat on Monday.
 
#11 ·
So sorry to hear you`re having heated issues ;)
BUT =
What with 100,000 miles coming up, that I`ve put on my Baby, I`ll be changing the coolant again at that time...
Thanks for the reminder to check my coolant before my 9 hours trip to Lil Sturgis & HSN Meet up...


Lets Ride & Meet,
D
 
#12 ·
I understand that in the instance I was talking about, the thermostat was just behaving as it should. I guess my question is why isn't it working Consistently? I'd doesn't work 95% of the time, then once in a while it pops on. Could it be a loose connection? Faulty wiring?
 
#15 ·
Ok this has got me really frustrated. Burped the system went for a ride, all seemed well for about 20-30 minutes. The fan was engaging when it should, I was happy, everything g was grand. Then the temp needle started to creep up, had a look at a stop light, the fan was no longer engaging. It works for a while, and then just stops. I'm reluctant to order an new sensor, or fan because they are working, but then the just stop. Any suggestions are greatly appreciated, and so is the help thus far. Thanks guys
 
#17 ·
When you say fan switch do you mean the thermostatic sensor?(same thing different name? that's just what I know it by, just want to make sure we're talking about the same thing) If so, I think you're right. that's really the only thing I can think to do next. I appreciate the input.
 
#18 · (Edited)
If you're referring to the switch on the radiator that the fan connects to, then yes. You know the fan functions, so about all it can be is the switch if everything else in the system is right. If you ground out the wire from the fan motor to the switch so it runs constantly with the key on, you can watch the temp gauge on a short ride and see if that's your issue. That would be where i'd have my money.
 
#19 ·
I have replaced radiators in cars because on a freeway drive the temp just keeps building because the radiator is restricted with scale or rust and can't keep up with the heat demand of the engine. But if your radiator is flowing well then you need to go after the thermostat which can be sticky as it moves open and closed, or the fan control circuit. Take the thermostat out for a test and run it to see the result.It is possible that the thermostat is sticking and won't allow flow, so the bottom of the radiator actually cools down, since the hot coolant can't flow down to the lower tank where the sensor is. Possibility.
 
#20 ·
So I tested the fan by bypassing the thermostatic sensor, and the fan goes on straight away when I turn the key. So, is there any reason I can't just bypass the sensor permanently and Have the fan run all the time? First thing that comes to mind is draining the battery, but could the alternator keep up?
 
#21 ·
Your stator would most likely keep up, but why wear out the fan motor instead of replacing a simple switch? Your running an already older fan motor with a limited service life. Would you rather push your luck at finding a used good fan motor next time? Install the proper new switch and be done with it. You never did mention about a test ride to check the overheat issue.
 
#23 ·
Ohhhhhhh man. Installed a manual switch for my dad fan, went for a boot, turned the fan on When my temp needle got to about half way, needle creeped slowly but surely right to the red line, turned the bike off, put down the stand and it discharged a bunch of coolant out the overflow. Thoughts?
 
#24 ·
If your fan was actually running it sounds like you need to start over. If it was my ride I would pull the radiator, flush and clean it, replace the thermostat for the cooling system and make sure it wasn't a wiring problem that kept the thermo switch from working.
 
#25 ·
I agree start over. The fan doesn't correct the problem.
The gauge appears to be telling you the correct information.
Did you pull the thermostat out and ride it to see the results?
If you pull the thermostat out, put it back together, and fill the coolant back up to the top, start the engine and rev it a little to see how the water pump is working and the flow. It should rise some when the engine is revved, but not so much as to blow out forcefully. If the radiator is clogged it will push out faster, and if a head gasket is blown it will push out very fast. See what you get.
 
#26 ·
Also a question for you WestCooper since we have the same bike . Does your temp gauge needle wiggle when you hit bumps ? Mine does but still stays at the reading. I suppose it is just the type of meter and it is not dampened as the speedo and tach are, so the needle wiggles. Just wonderng.
 
#27 ·
That CAN be done...
I`d do it too, JUST as a test though, NOT as a permanent fix...
IF the fan keeps the gauge where you want it, then replace the control switch for it, This is where I`d bet my Money too...
Lets Ride,
D
 
#28 · (Edited)
Swifty2014, my temp needle doesn't wiggle at all, it just likes to hang out in the red. So I opened up the rad cap, topped off the fluid, started her up, cracked the throttle a bunch of times, the coolant went down nicely and came back up a bit, didn't come all the way back up until I shut it off if I remember correctly. Is this an indication that the water pump is working correctly? I turned it on again with the cap off, while the engine was still warm, that's the only time I got a bit of a coolant eruption. Is this to be expected? Went for a rip in traffic, not gridlock, but through the city. Turned the fan on when the needle was about 1/3 up the gauge. Temp dropped when I could keep my speed up, and rose at lights. Got close to the red but not quite in it after about half an hour, which is when I got home. I'm actually pretty happy with this result. Is this just a matter of old bike in traffic? I'm going to go for a highway ride tomorrow. Will report back. Thanks again!!
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top