Anti-freez

[puma]

I recently noticed my anti-freez was low so I added more and today, I notice the hose leading into the thermostat is kind of bloaded and not soft to the touch. Does this mean i have a bad thermostat? Any help please.

[monarch]

No a bad thermostat cannot cause a coolant leak. So somewhere else in the cooling system there is probably a small coolant seepage leak. On a 10 year old Lexus like yours, seepage leaks are almost always minor and will not likely escalate into a big leak anytime soon. However, a leaky water pump is serious and should be replaced immediately if it leaks.

If any of your coolant hoses and hose clamps have ever been changed I would check those first because auto parts store hoses and hose clamps are of lower quality than factory original hoses and clamps, plus aftermarket hoses are not metric so they fit either a little too loosely or tightly.

The factory original hoses and clamps are good for 15-25 years and owners often change them too early and

then install lower quality and less well fitting auto parts store hoses and clamps. Owners often make another mistake by replacing only the coolant hoses they can plainly see under the hood like the radiator hoses while ignoring the other smaller coolant hoses that are less accessible and where seepage leaks can occur.