XJ cooling system

doesn't dex cool and green mix to form sludge?

stan_d wrote: doesn't dex cool and green mix to form sludge?

Indeed it does!

I thought I got it all out. Apparently not.

Yes it will, it turns into brown sticky goo. It will clog hell out of a radiator and heater core too.

stan_d wrote: doesn't dex cool and green mix to form sludge?

Yeah, but it takes a year or two, all the dex cool issues stem from people not changing it out every couple years(as GM more or less claimed it was a lifetime fill).

Less than a year in this case, to make brown chunky mess

Assuming you catch it early, what is the recommended procedure for flushing it out before it goes chunky?

GM's procedure was to flush the cooling system thoroughly with straight water as soon as possible, then change over to the green three year. It appears the dexcool is what goes brown and gooey, not the green stuff. So keeping the dexcool contamination to a minimum is the key.

I'm waiting to see what happens with the OAT purple stuff when it gets crossbred. I'm gonna say it won't be pretty. It's supposed to be a further development of dexcool formulation.

This past weekend I flushed it, and after seeing what came out, added another gallon of vinegar.

Nothing too solid, but definitely lots of brown cloudy mess.

Two more weeks or so and I'll repeat.

Timely thread, I'm just about to do a vinegar flush on my G13A's rebuilt engine. The coolant passages are coated with scaly crud, and the radiator's not super clean either.

When did they stop using Dexcool in these? Would our 2000 have it? This might explain a lot.

Swank Force One wrote: When did they stop using Dexcool in these? Would our 2000 have it? This might explain a lot.

They never started putting Dexcool in XJs. Some doofus put it in there a year ago.

While you are working on flushing the dexcool out, take a look at the lower radiator hose.

Make sure the lower hose has the spring in it so it doesn't collapse.

The hoses can get real soft, and collapse restricting flow. That is even more likely since there is sludge already restricting flow.

tuna55 wrote:

Swank Force One wrote: When did they stop using Dexcool in these? Would our 2000 have it? This might explain a lot.

They never started putting Dexcool in XJs. Some doofus put it in there a year ago.

OH!

I feel better now.

jstand wrote: While you are working on flushing the dexcool out, take a look at the lower radiator hose. Make sure the lower hose has the spring in it so it doesn't collapse. The hoses can get real soft, and collapse restricting flow. That is even more likely since there is sludge already restricting flow.

Replaced it for that exact reason. Good idea, though!

I had a 93 that ran warm. Turned out the radiator was loosing fins in between it and ac core. Finally started leaking. I put a new one in never ran hot again.

Well it took three complete flush cycles with a 50/50 vinegar mix in there for a few weeks at a time, but it finally looks like the coolant is coolant, and the thing stopped overheating. We'll see if it stays this way when it gets warm again in the spring...

Now to fix the neutral safety switch...

And to check out the wobble in the front end...

And then I guess to try and get the radio and CB and radar detector figured out...

I'll admit I didn't read every post in this thread. Long story short XJ cooling is notoriously poor. A common upgrade are electric fans from a ford Taurus. taurus fan links

Update: Everything is great with the XJ still!

I even fixed the weird transmission-mounted neutral safety switch, and the front end wobble was a tire getting corded.

I replaced the radiator yesterday. I hope she pays me the $85 on payday like she promised. Apparently either age or Dexcool terrible-ness got to the end tank. She's pretty easy to work on.

She called me over last night to check on a no-start-with-new-battery condition to find the goomba who put the battery there overtightened and ruined the terminal, so I fixed that.

As I'm handing the keys back, she says "It's making this awful squeaking noise..."

The water pump is toast. A year and a half years old and it's coming apart, the shaft is wobbling in the housing. Hurray!

Man - she should fix the pump and RUN away from this one as soon as possible.

MichaelYount wrote: Man - she should fix the pump and RUN away from this one as soon as possible.

Trust me there is no selling it.

"She" will probably fix the pump this weekend instead of spending time with Tunatruck. It's under warranty so it's free, but it does mean that "she" has to get it off during business hours, and that might be a challenge.

The battery was dead because she never charged it. It was a neat story, but essentially I had an hour and a half to get the Jeep, get it home, pull the pump and get it to O'Reilly's.

It got icky when it stalled at an intersection and I was waving jumper cables at passing cars. Neat when two cops stopped to help me, and were totally cool about me being armed.

I ended up getting it done, and getting to O Reilly's, and checking out a sweet Regal in the parking lot owned by one of the counter jockeys. It had a nasty air bubble problem, too, so I ended up pouring water down the thermostat neck and into the cylinder head.

Anyway, it's done, but Tunatruck got no love tonight.

It's leaking again!

She left it at the kennel (where she works). I got there at 9 or so, listened to the very angry dogs barking like mad at me while I figured out what was wrong:

$0.89 and 1.5 hours. I blame the corrosive Dexcool.

Here she is, by the way:

And Tiffany will grab a ride to work to get her Jeep back and see if all is well.

The coolant was brown again, but at least watery and not chunky. It hasn't overheated in a long time.

She called.

High oil pressure (off the scale) and overheating plus icky noises but it ran enough to get her home.

Haven't gotten to the Jeep yet. Guesses?