[Dirt_Dad]

I posted this on VSRI, but also wanted to get as many opinions as possible.

My bike started filling the overflow tank when first shut off, then emptying the tank 90 seconds later with lots of slurping and gurgling sounds. From what I've been reading that is a sign of air in the system. With the bike cooled off the tank is sill empty and upon opening the radiator cap the level is clearly down. I saw one thread where a radiator cap took care of the situation. Looking at my cap, the coolant does not appear to be escaping from the cap. Also the hoses appear to be free of leaks. But the loss of coolant is obvious when looking at the area where the radiator bolts to the cylinder head.

I am unable to see any coolant running along the bottom of the radiator to the bolt. The only logical explanation I can come up with is the place where the bolt flange is welded to the bottom of the radiator is split and causing the leak. Looking at the pictures is there another possibility I'm not considering?

Cap is dry

cap side hose is dry

left side hose is dry

underside of radiator is dry

bolt is very wet

 

[T3/T4 Hybrid]

John have a shop do a pressure "leak down" test on the radiator/cooling system and cap. If the cooling system has any kind of leak it will show up.


‪Universal Radiator Pressure Cooling System Leak Tester‬‏ - YouTube

 

[Dirt_Dad]

John have a shop do a pressure "leak down" test on the radiator/cooling system and cap. If the cooling system has any kind of leak it will show up.


‪Universal Radiator Pressure Cooling System Leak Tester‬‏ - YouTube

I know most shops won't attempt to fix an aluminum radiator. Think they will perform the test?

 

[Attackturtle]

I would think so. It will confirm what part you need to replace.

 

[Alpster87]

I agree with to having the system checked for leaks ,but make sure they empty it of all coolent or they will not have preformed a proper test ,the probable culprit is all the hose clamps around the thermistat which can be reached with a little interptation and enginenuity...in other wards your probably going to bleed a little ... The leak in your photo looks more like an oil leak coming from the top cover ... and you need to put the clamp on the coolant return hose back in its proper position closer to the rad cap ... hope this helps you out ...:thumbup:

 

[T3/T4 Hybrid]

I know most shops won't attempt to fix an aluminum radiator. Think they will perform the test?

Yep... I'm sure most shops will do it for a price. I thought Aluminum radiators could be repaired. It's the fiber tank radiators that are to much of a problem to get fixed and is cheaper just to replace.



If you want to save a couple $$ you can do the test yourself by going to Autozone and put down a deposit on a loaner tool.

 

[Alpster87]

If the shop cant fix it themselves they will usually have an automotive rad repair shop do it for them ...

 

[bwringer]

I just had my Vee's radiator repaired by Myler's out in Utah. They're about the only place that will repair aluminum motorcycle radiators by welding instead of farting around with epoxy. Very reasonable cost, I thought ($80), and the repair looks great and is working perfectly.

With that said, you've shown us an oil leak but not a coolant leak. Your radiator actually looks fine so far.

First determine where the antifreeze is going. If it's not ending up on the ground, a badly blown head gasket is possible, although you probably would have noticed the huge clouds of foul-smelling white smoke following you everywhere.

Also, check the oil for AF -- does the oil look like mayonnaise, or can you see green drops in the oil? It's possible for the water pump to leak and end up in the oil, although it's not common.

 

[Improperly Torqued]

First determine where the antifreeze is going. If it's not ending up on the ground, a badly blown head gasket is possible,

If your leak test shows nothing remarkable, park it and have the oil analyzed before running it again. Costs maybe $30 (I use Blackstone Labs, but there are others).

 

[danketchpel]

I would reclean and dry that lower mount area and then simply check it when it's hot, that's all the leak down test you need. The system is pressurized when hot and if it's leaking you will see it getting wet.

If the system isn't holding pressure due to a leak then the hoses will not be firm to the grasp when it's hot, simple test.

I'd second the choice of Myler's in Utah for radiator repairs. They did an awesome job on one of DRZ radiators that looked like a banana when I sent it to them, came back nearly perfect and is still leak free 9 years later. You simply can't beat their quality, price, and speed. The price of new radiators is through the roof.

 

[Cake_Kat]

That clamp looks pretty far from the nipple. Make sure it isn't constricting the hose.

 

[Dirt_Dad]

Since it was under the radiator and above the valve cover I didn't consider that to be oil. But I don't know what airflow is down there, so I guess it could be oil getting pushed up. That would be easy to deal with since I'm due for a valve check and I do have an extra gasket for the job.

If that's the case, I still need to figure out where the coolant is going. Probably need to check the other end of the hose (non-radiator side) to see how those connections are holding. I was so focused on the bolt that I never looked beyond the radiator.

 

[Scott E. Bonds]

You may have a head gasket leak in addition to an oil issue.

The head gasket can fail between a water jacket and the cylinder and cause the symptoms you describe. The cylinder compression will cause the coolant to get pushed into the recovery bottle and when shut off and cooling, the engine will suck it back inside the rad. With each cycle of this you can loose some coolant.

In this case, you likely will NOT see oil in the rad nor coolant in the crankcase either. And the leak can be small enough to not see it in the exhaust stream.

The tell tale sign of this is a build up of tannish deposits on the spark plug of the bad cylinder from burning the antifreeze. The engine may also start up with a stumble that clears up pretty quickly once the coolnat is burned out of the cylinder.

 

[Dirt_Dad]

I’m going to do a valve inspection in the next day or two. That will give me a chance to inspect the plugs for any glazing and to take care of that valve cover gasket. If I see no plug glazing and cannot find the source of the leak from any hose I will probably start with the simple stuff. A guy on VSRI reported exactly the same radiator symptoms as mine. Ultimately he tracked it down to a faulty radiator cap. He installed a new one and his problem was solved for years. That seems like a reasonable next step.

 

[Scott E. Bonds]

Thats sounds like a good idea. If the rad cap is releasing with too little pressure it could do it.

The plugs won't be "glazed" if burning coolant...it is more like a crusty buildup...it will be obvious.

Good Luck

 

[T3/T4 Hybrid]

I’m going to do a valve inspection in the next day or two. That will give me a chance to inspect the plugs for any glazing and to take care of that valve cover gasket. If I see no plug glazing and cannot find the source of the leak from any hose I will probably start with the simple stuff. A guy on VSRI reported exactly the same radiator symptoms as mine. Ultimately he tracked it down to a faulty radiator cap. He installed a new one and his problem was solved for years. That seems like a reasonable next step.

You can also pressure test the radiator cap. Im not for sure what pressure the VStom should hold at but most cars are around 14 to 16 psi.

 

[Dirt_Dad]

I just picked one up on the way home this afternoon. Used the same model the guy on VSRI used to correct his problem.

I've pulled the plugs and they look completely normal. So I'm thinking I may have lost the coolant out the top of the overflow tank tube. Not seeing any other places where it may have come from, but still looking.

 

[EC90T]

A guy on VSRI reported exactly the same radiator symptoms as mine. Ultimately he tracked it down to a faulty radiator cap. He installed a new one and his problem was solved for years. That seems like a reasonable next step.

I'm betting that this was the problem. I'm sure the problem will be cured with the new cap.

I'm filing this bit of info in the back of my head for future referance.

 

[honest bob]

That (oil) liquid on your front cylinder head cover left side is probably oil leaking out where the cover gasket meets the half moon shaped rubber seals. The only place that is very hard to get liquid gasket to seal. (the most likely place for a cover to leak.)
The coolant lost from the overflow tank due to a defective rad cap, should show up where ever the overflow tank overflow tube exits on your bike. Underneath it along the bottom somewhere. I would not run the bike if it is not holding pressure because the coolant will boil at lower pressures. This may cause some extremely hot spots in the motor. Add to that the possibility of coolant on your rear tire :yikes:.

 

[Dirt_Dad]

Well it was 95 degrees with an unreachable dead rotting carcass under the floorboards of my barn providing a lovely aroma. What better time to take the bike down and do a valve check and search for a leak.

I was mildly surprised to find the the rear cylinder intake has become a little loose, but otherwise everything was as expected. And no signs of leaking coolant from any hoses I could find. New valve cover gasket installed ran out of time for much more.

Based on tonight's findings I'm going to continue to stick with the theory the coolant loss was from the overflow tube. Which means I was getting a nice drip of lubricant for the rear tire on Sunday as I rode the 300+ miles home from Upstate New York. I'll get it all put back together with a new radiator cap for the weekend and see if my theory holds up.