TrollHammer

Just bought a 94 ZJ, and was changing the thermostat today, but as I was cleaning the hose and pipe before calling it donr and noticed what looked like grease inside the hose.

Coating the inside of the upper radiator hose (but not in the pipe or the thermostat, or inside the block, now that I think of it), there was about 1/4" of black gummy/rubbery residue. Im guessing this is some sort of stop leak.

Is there some easy way to clean this gunk out of the system without either scraping out the inside of all the hoses or replacing them?

Gorillaxj

I would just flush it. drain the coolant. fill it up with water from the hose, let it run and warm up for the T/stat opens. then open the petcock and let it drain into a 5 gal bucket while you continue to fill the radiator. as it cycles threw it should drain most of the loose stuff out. once its clear water for a while shut it off. Drain the water, and add non-mixed coolant to get it back to the 50-50 mark. the bucket should show you what you have gotten out.

A lot of the times you can't get it all out without replacing parts like the radiator, heater core, ect. as it get stuck int he small ports. but flushing it out should be good enough.

TrollHammer

thanks for the quick reply!

So you think Im on the right track thinking it is stop leak?

Gorillaxj

No problem, thats what it sounds like to me, some stop leak can have ground up pieces of rubber, some have cardboard flakes, others have weird chunky things lol all mixed with a weird paste that I have seen stain plastic and aluminum. I would start with a flush before anthing. If anything odd comes out then I would go from there.

4Doors

I would think some radiator flush would help loosen the gunk up since it's pretty good at getting crud out of the system. Run it for just a bit to give it time to work and do it several times if necessary, but don't be surprised if you end up needing a new radiator.

TrollHammer

Its almost like they should ban the stuff. Seems to me the junk does more harm than good. Egg would be way easier to flush out, and if you're out in a situation that you actually need an emergency fix, its knly intil you can make a proper repair.

Any thoughts on the electrolysis issue on the timing chain cover? I have had three of these V8s, and evrry one has had issues with the water ports eroding where they meet the engine block, leakong mildly.