Radiator gunk

[Tchajagos]

What is going on here? It's like mud. Not oily at all and washes right off.



It was fine a few months ago when I bought it. Maybe it all came from the heater core when I used it? I haven't put anything in it. It had a newer radiator when I bought it I'm thinking either the previous owner used a ton of stop leak or some kind of chemical reaction. Anyone seen this before? 97 ranger 3.0l auto.

[funinthesun95]

Low coolant or a leak bringing air into the system can do that.

Mixing the different kinds of coolant can also cause a reaction. like mixing old school green with the new stuff cars use... red orange yellow


most likely leak or air

[Garlic Bronco]

looks to me like some one put bars leak in it at some point

[VintageIronFab]

I would just start anew with everything vs. trying to clean parts-- ebay has some great deals on radiators, waterpumps, thermostats and heater cores with free shipping and no tax.

[Wrightracing.net]

I say flush the whole system with a detergent made for cooling systems. If that gunk is from some type of stop leak, then you may have a leak somewhere, then deal with it properly and fix it. I know it is easier just to be a parts changer, but diagnostic skills are a great thing to developed.

In 30+ years of working on cars, trucks, motorcycles and anything with a motor I have never seen gunk like that in a cooling system. I don't think they read the instructions on the stop leak product. You don't fill the whole radiator with a case of the product.