Diarrhea

[Ahoragi]

Need help diagnosing a boo boo on a XJ. It is crunchy in texture and smells like chocolate. The heater core hoses are clogged full of this crunchy substance. The rest of the hoses are clean. The radiator drained clear pretty quickly. What was odd was there was no sign of green or red coolant. It appears to be water.

I think the heater core has imploded maybe?

I've had oil and coolant mix and it does not look like so I'm thinking rust.

 

[StG58]

Need help diagnosing a boo boo on a XJ. It is crunchy in texture and smells like chocolate. The heater core hoses are clogged full of this crunchy substance. The rest of the hoses are clean. The radiator drained clear pretty quickly. What was odd was there was no sign of green or red coolant. It appears to be water.

I think the heater core has imploded maybe?

I've had oil and coolant mix and it does not look like so I'm thinking rust.

View attachment 23348 View attachment 23349

Block and head rust. Corrosion byproduct. That poor XJ is in desperate need of a chemical flush. It should clean out with enough effort and time. Plan on a water pump, thermostat, possibly a heater core and maybe a radiator. That crap is errosive and clogs up everything.

And that's a good reason to run the correct antifreeze in the correct concentration. Been there, done that. Cost me money.

 

[Ahoragi]

Can you elaborate? What exactly caused it?

Chemical flush? What should it be flushed with?

The radiator flushed out clear pretty quickly.

 

[Chris]

Can you elaborate? What exactly caused it?

Chemical flush? What should it be flushed with?

The radiator flushed out clear pretty quickly.

The most likely cause was running tap water in the cooling system. So many people think it's okay to take tap water (or hose water) and use it in your cooling system. HUGE mistake! When I was a teenager I did that with my first vehicles, and I learned 1 year later how quickly it turns your coolant (and cooling system) into rust. Mine looked similar to yours (though not as bad).

All the minerals in tap water are the cause of this. You need to be using pre-mixed coolant, or if you mix it yourself, distilled water.

It doesn't take long for tap water to start doing this either. On my first car, it took maybe a few months at most.

 

[JMT]

Need help diagnosing a boo boo on a XJ. It is crunchy in texture and smells like chocolate. The heater core hoses are clogged full of this crunchy substance. The rest of the hoses are clean. The radiator drained clear pretty quickly. What was odd was there was no sign of green or red coolant. It appears to be water.

I think the heater core has imploded maybe?

I've had oil and coolant mix and it does not look like so I'm thinking rust.

View attachment 23348 View attachment 23349

A bunch of Nestle Crunch bars?

No, really, it’s rust. Contrary to what people often say, you should never put water in a radiator (ok, for an emergency), but it will cause rust. My FIL did that in a 96 Mustang and it rusted it out and had to replace. Messes other stuff up too.

 

[JamesAndTheSahara]

A bunch of Nestle Crunch bars?

No, really, it’s rust. Contrary to what people often say, you should never put water in a radiator (ok, for an emergency), but it will cause rust. My FIL did that in a 96 Mustang and it rusted it out and had to replace. Messes other stuff up too.

You can use distilled water if you are mixing with a concentrate (Its what most pre-mixed solutions contain).

Quote from the instructions of an Antifreeze company most people use:

"Flush and Fill:
DRAIN the cooling system to remove loose rust and sediment from the radiator. Follow owner’s manual (ILLUS. 1a).
FLUSH the system using a quality product like Prestone® Flush and Cleaner to clean the engine block (ILLUS. 2a).
FILL with Prestone Dex-Cool® and distilled water to achieve the freeze-up/boil-over protection indicated on the back of the bottle (ILLUS. 3a)."

Sometimes it is just easier to buy the 50/50 pre-mix though, I certainly would for a trail ride item.

 

[StG58]

Can you elaborate? What exactly caused it?

Chemical flush? What should it be flushed with?

The radiator flushed out clear pretty quickly.

It's the chemistry of the water acting on all the different metals in the cooling system. Part of it is oxidation and part of it is electrolysis. The combination causes the crunchy chocolate thing. Additives in antifreeze buffer those two reactions and prevent that. PH has something to do with it also, but I don't remember exactly what.

Over the counter cleaners will usually barely knock the crud back. Find an old school parts place and talk to the crusty old fart behind the counter. You'll probably need two different cleaners, one a base and one an acid. Don't mix'm! That combination works. Run one, flush thoroughly, run the other, flush thoroughly, replace thermostat and water pump. You'll be good to go after that for a long time. I don't remember which one to run first, sorry. A little google-foo should reveal that.

Run 50-50 Jeep recommended anti freeze and distilled water. HOAT You'll end up buying two gallons, and have a bunch left over.

 

[Tj04]

2x on distilled water. Don't listen to the guys that say don't bother. Distilled water is like $80 cents a gallon. Under $2 bucks for enough water. I don't get why people use tap water.

I will also say you can use Oreileys universal coolant. I've called multiple jeep dealers and spoken with the technicians and all have said it is 100% ok, and old formulas didn't work very well as univeralcoolants but newer stuff works in almost everything.

 

[Ahoragi]

Thanks for all the info. It was very helpful. So it seems like I will have to have a system flush at a shop because there is no way to do a flush at home that is powerful enough to force the crud out of the heater core. It seems like it all gathered up and clogged the core and started backing up through the core hoses.

 

[Ahoragi]

Well I was bored after work and decided to hose out the heater core. Lots of chocolate came out and then it went clear. I flushed both ways and it was clear but I still had a layer of rust residue stuck to the interior of the hoses. I also did a full system flush while it was running. I'm hoping the flush chemicals I bought mixed with distilled water will flush the rest of it out.

You guys say Tap water is a no no. What about well water? It is just as bad? I have a well. I don't plan on using the well water but was just curious.

 

[Mike_H]

Well water is probably worse than city water. Well water will probably have MORE of the dissolved minerals than City.

FWIW, don't use tap water in your golf cart batteries either. Same problems...

 

[Bird]

Well water is what most consider tap water ,comes from a faucet.
I actually use well water in all my radiators but i have soft water with a neutral PH and goes through a Hydrogen peroxide tank.