Weird cooling issues

[alchemist]

So about a year and a half ago, I put in a new water pump (old one was leaking) and a new SuperStant Thermostat. Even before that, I had tried to flush the coolant passages and radiator prior to the change. What I kept seeing then and am still seeing now, in my radiator, is brown gunk and deposits. The brown sludge is coating the inside of the radiator. I empty and replace the coolant and it comes back. Now am getting cooling issues (overheating on hot days, not past the danger point, but on the "A" and even "L" on my gauge. I have never seen this before on any car I've owned, but thinking it may be one of two things:

1. transmission fluid is leaking into the radiator fluid, in the cooler on side of radiator? I've seen this before in a Chevy, but what you'll also see is when the engine is shut down and cool, coolant goes into the transmission fluid (bad). this isn't happening here.

2. engine oil is getting into the coolant through either a head gasket or an intake gasket failure?

I would like to simply go ahead and change out the radiator, but that may not be the solution here.

Thoughts./suggestions?

[knucklehead0202]

Well unfortunately you have to start somewhere, so I'd start at the cheapest place. Are you notably losing trans fluid or coolant? Perhaps you just need a professional cooling system flush. If at any point the wrong coolant was used, or it sat a long time, the tint of that crap could just be thick in your system. A good radiator shop might be able to provide some insight just by looking at it too.

[sly]

it was really thick in my 93. professional flush eliminated a lot, but I ended up doing that F150 radiator swap and that seems to have helped a lot. I probably need to do another flush anyhow to help get stuff out of the heater core and the bottom of the block... but meh. temps are rock solid now.

[alchemist]

Well unfortunately you have to start somewhere, so I'd start at the cheapest place. Are you notably losing trans fluid or coolant? Perhaps you just need a professional cooling system flush. If at any point the wrong coolant was used, or it sat a long time, the tint of that crap could just be thick in your system. A good radiator shop might be able to provide some insight just by looking at it too.

I'm not losing transmission fluid, but I am losing coolant through the overfill container. It's almost like there's a clog in the radiator and it's not circulating thru the block very well. You are right, my heater core gets clogged continuously. The car did get driven very infrequently for a while - an older man owned it. When I bought it in 2012, it had about 69,000 miles on it. I can't imagine how or why anyone would've used the DexCool crap in there, so I don't think that happened. I did Prestone flushes, multiple ones, over a year ago but there's gunk/sludge galore in the radiator again. I may try the route of pro radiator shop - not many of those left around here anymore.

[knucklehead0202]

I've been blessed with having several good radiator guys local, of course I haven't had any cooling system trouble in a long time. But yeah, a pro should be able to sort you out or at least point you in the right direction. For whatever reason, every radiator shop I've ever been too has had really cool people working there that are unusually helpful and pleasant. Wish my experiences with mechanics and other things were as good.

[sly]

are you sure the radiator cap is good. if it's bad it'll do the overflow tank spray.

[gadget73]

I'd shitcan the radiator if its got that much garbage in it. Its probably half clogged anyway. Flush the rest of the motor extremely well while its out, otherwise all the garbage that is laying in the motor will just move into the new radiator. Might be worth running a couple treatments of the cooling system cleaner through with the old radiator first though, even if you do end up replacing it. That should help get the garbage out of the motor if nothing else.

Trans coolers can leak into the water, but you'd see it as an oil film, not just the rusty nasty crap.

Replace the fan clutch too if you have not.

[alchemist]

Thanks Sly and Gadget,
Yes, I'll just get a new radiator cap. Mine is original and may be burping a bit. I can get a new radiator too. Can a radiator shop do any more cleaning than I could, using the Prestone heavy duty ass stuff?

[sly]

if it's bad, they typically get the hose out and just run water through the rad and engine until it runs clean. That's what they did for my 93 vic when I had them do it.

[gadget73]

they can also use a mild acid to remove mineral deposits, but white vinegar will do the same thing. Get some hose that will connect the top to the bottom, fill it with vinegar, and let it sit in the sun for a day. That should eat out any hard water crap that may have built up over the years, but silt and loose stuff will usually come out well enough with water. I've found that removing the radiator so you can blast in there from both openings and at various angles can help loosen stuff up too.

[DerekTheGreat]

I'd shitcan the radiator if its got that much garbage in it. Its probably half clogged anyway... ...Replace the fan clutch too if you have not.

^^^What he said.

Ashley was having overheating issues with her '89 TC for the longest time. Then last winter the thermostat stuck open so we replaced thinking that might've solved the problem but no bueno. I was about ready to throw a water pump at it but the fine folks here suggested we replace the fan clutch and after doing that, car doesn't over heat any more.

We also bought a '88 GMC that had never seen a coolant flush, stuff was black. We're three flushes in and the coolant is only now becoming a murky green. Radiator now leaks but I plan to flush it a few more times and let gunk collect in there before changing that & the old T stat out.

[alchemist]

Thanks guys. I flushed the heater core thoroughly yesterday, then removed the thermostat and did a backwards and forwards flush of the engine. Good clear water with high pressure both ways. Put on the new radiator and have run her about 20 miles and it's actually green again and running cool (still need to drain and put in the thermostat). The old radiator was the culprit. I did forget at first to put sealant on the transmission cooler adapters that thread into the radiator (they are NPT and would need tape or thread sealant) so was leaking DexIII on the ground. I removed and taped with PTFE tape and she's all fine. Of course, no tape applied to the actual line to adapter, which is a flare fitting.

Didn't replace the fan clutch - it seemed to have good resistance so it should be still good.

[porschpow]

I usually did the backflush system.

You could buy the kit at any FLAPS, it's cheap, and the effects are great!

[gadget73]

I have to admit, I like the later NPT to flare adapter setup. Much less shitty than the quick connects I have. Those at least never go bad, my stupid quick connects go bad if you try and move the line after they have been in place for a couple years.