Lately I have been loosing coolant somewhere, I can hear lots of hissing (coolant hitting something very hot and evaporating) after driving but I haven't had time to crawl underneath yet. Now, when I was refilling the coolant into the radiator directly, I discovered something worrying . The cap was covered with black grease like substance, like the kind you find on the outside of the oil pan or engine, not very greasy but more muddy consistance almost with small particles.It didnt seem disolved, just sticking to the radiator and cap(I hope you get what I mean). The first inch of the radiator hole was also covered. Now im worried :boohoo: . Anyone know whats wrong? Blown head gasket?

 

Thanks

 

PS Im at 136k miles. No other reduction in power or any other abnormalities on the car.

check for a crack on the pasenger side plastic end cap. The crack would be facing the front of the car.

I'll do that. My last radiator was cracked there and got a used one from a dealer because I was on the road when the car started overheating so had no choice.

i've been gettin that black crud on my radiator cap too for about 14k now.. on the first long trip (600 miles) i took it lost about a half gallon of coolant..

 

once i filled it back up it was fine again... i'd still like to know what all the black crud is... i figured if it was a head gasket it woulda blown already... but it runs great no problems..

 

i'm pretty sure that the water pump is the culprit on the leaking, it ya drive over 70 it spews a little.. below that it doesn't leak a whistle...

 

289k original

You might want to test the coolant fluid for Carbon Monoxide. Sounds like compression/exhaust gas is pushing in from a combustion chamber. Only takes a tiny leak, you might not even find it when you remove the head gaskets.

 

Or, flush the cooling system. Means a lot if it hasn't been done in a while!