Nagging doubts
 

Alternative title: "Get a grip!"


Briefly: knocked the SV over a couple of weeks ago, punctured one radiator hose (now replaced) and bent radiator brackets, pushing rad 1 inch to left (now straightened).

Since then I've ridden approx 150 miles. Coolant level in reservoir normal, coolant level in rad normal, coolant temp normal (I've never seen it go above 3 bars and I've never heard fan come on in 8 years).

So, why do I have a nagging feeling that the radiator has a leak?

On my return from one 35 mile ride, there was liquid on the left side of the tank, just above/behind the rad (on the plastic trim, if you're familiar with Gen3). I wiped it off before my brain thought: "where did that come from?" Roads were mostly dry apart from a couple of small wet areas extending no more than 100 ft. Could that be the liquid source? Possibly but it was extremely localised if so. On 2 subsequent rides no more liquid has appeared.

You know how coolant feels in your fingers? Slimy is the best way I can describe it. I wiped the top of the rad with isopropyl alcohol so it was squeaky clean but yesterday I noticed it was slimy again. There are no drips anywhere.


Obviously, the best way to resolve this would be a pressure test but that means either buying a kit or taking it to a dealer.

This is how I understand the cooling system: it's a sealed, pressurised system running at approx 15 psi. If pressure gets too high coolant is expelled into remote reservoir and as it cools coolant is drawn back into system.
If I did have a rad leak, the system wouldn't be able to push/pull coolant and rad coolant level would gradually drop. It hasn't done that so either my understanding is wrong or I don't have a leak.


Why do I think of these things when I'm trying to sleep?

Re: Nagging doubts
 

Thats almost how the system works except the rad must be completely full then as the engine heats up the coolant expands and opens the rad cap valve to discharge excess to reservoir. As you say on cooling another valve in the cap opens under rad vacuum and coolant is sucked back. This means that the cap has to seal not only at the bottom of rad filler but also at its top otherwise coolant can leak out on warm up or air get drawn in on cooling....

Re: Nagging doubts
 

Too much coolant in the expansion tank?

Re: Nagging doubts
 

Pleased to hear you're cancer free Bibio!


I think it's a case of too much worrying. :rolleyes: I need to get a grip or as my friend said: "just ride it!"

I just did another 60 odd miles this morning and no sign of any liquids where they shouldn't be.

Re: Nagging doubts
 

If you do want to pressure test the system just connect a foot pump to the radiator overflow pipe. I test my old car like this but am careful to keep the pressure at sensible levels as obviously the radiator cap cant lift! Also open the cap afterwards very slowly as although not hot the pressure trapped in their can make the coolant shoot out....

Re: Nagging doubts
 

I had same problem with mine after first coolant change. Too much in expansion bottle. As you said a cppl rides later and it all settled down. Now i only fill half then top up.

Re: Nagging doubts
 

If it was damp the next day can you be sure it wasn't anything more than condensation mixed with a tiny bit of paranoia? I've had the same nagging feeling after changing a rad (car a few years ago that sprang a leak) but it was all fine. I kept looking for leaks and was convinced everything was a potential issue but the levels never moved and after a few days I stopped looking for something that clearly wasn't there.

Hope it's all good.