Head gasket or coolant problem?

JDaPP · **Posted:** Sun May 15, 2016 7:23 pm

A little over a month ago I noticed my coolant had a tan/light grey sludge in it. Everything I found pointed to wrong coolant added. I had system flushed at jiffy lube with hoat coolant and then I drained it again 2 weeks ago, pulled all the hoses and reservoir and cleaned them out as well. Added distilled water and have been just sucking out the top as more sludge appears with the assumption that the system would take a while to get all of it out and I would flush again every couple of weeks.

My concern is it doesn't seem to be getting any better and I added oil two weeks ago and it is down more than I would have expected/am used to seeing after two weeks. More water than sludge compared to a month ago but still more sludge than expected.

I have done the pressure talked about on the forum (cool vehicle, run for a minute, check pressure) and there is no pressure build up, temps are all normal and jeep is running great. 117k miles. I do not have arp studs, do have gde eco tune.

Am I just expecting the sludge to clear up faster than what is realistic or do I have a head gasket leak?

Mountainman · **Posted:** Sun May 15, 2016 8:10 pm

If you're not having to add any coolant, then it's probably just from the wrong antifreeze. Does it consume coolant?

Make sure you're only adding about 6.4 quarts of oil, or is it 6.5? The dip stick full mark is too much on these. After that, you shouldn't see much oil consumption

JDaPP · **Posted:** Sun May 15, 2016 9:13 pm

Not having to add coolant. Filled oil to ~min mark which is the usual mark for me with 6.4. It is about halfway between min mark and bottom of dip stick after 2 weeks and ~600 miles highway/city driving

geordi · **Posted:** Sun May 15, 2016 9:18 pm

Ok - a couple of things:

The pressure test sounds good, and I haven't seen one of these yet that passed the pressure test and yet still had a head gasket leak. You *will* have one eventually though, unless you put in the studs.

Oil fill after changing the oil is 6.4 quarts with the stock oil filter size, or 7 quarts exactly if you get the slightly larger Mobil 1 M1-301 filter or a direct cross reference to that one.

The sludge in your coolant system can indeed take a long time to purge out, especially if you aren't flushing each component directly with flowing water from a hose. Chances are, most of the jello is living in the heater core and you will need to purge that directly to get the goop out the fastest way.

You need to remove the hoses from each major device (Heater core, radiator, and engine block) and then connect a water hose with a controllable shut-off to one side of each device's connections. Slowly ramp up the flow through the device, so that you can ensure you aren't overpressurizing whatever it is (a garden hose shouldn't be able to hurt anything, but the goop CAN block passages and cause a pressure issue) and watch for whatever is pushed out from the other connection. If you have clear water coming out, then move on to the next thing.

I would expect that you will see goop come out from the heater core and the radiator, the engine is very large and you probably won't be able to purge that directly very easily, but maybe I'm wrong about that. Getting all that crap out is the main goal however, but don't use any kind of flushing products, they could react again with the HOAT.

FYI: You can buy HOAT coolant at NAPA or Advance auto, both sell "Xerex G-05" which is an acceptable HOAT for about $15 a gallon. Don't flush with this, it is way too expensive for that! Just use clear water, and lots of it. There isn't an issue with flushing with tap water, then drain the system one last time, and fill first with the pure coolant (1.5 gallons is probably all you will get into it) and then with the engine running, fill the rest to the very top with clean water. Use distilled if you have hard water, but most people can use their tap and it will be just fine.

JDaPP · **Posted:** Tue May 17, 2016 11:24 pm

Appreciate the help. I will have to look around to see if I can find someone that can do the studs.

geordi · **Posted:** Tue May 17, 2016 11:47 pm

JDaPP wrote:

Appreciate the help. I will have to look around to see if I can find someone that can do the studs.

LOL... At the risk of repeating myself too often - I'm the travelling mechanic, hit the email button below my post to email me and we can go over the details. The studs are a big job, but I do that in conjunction with fresh rockers, elbow kit, glow plugs, and a complete timing belt kit with water pump since the labor completely overlaps. I've done this now more than 20 times. :JEEPIN:

Mountainman · **Posted:** Tue May 17, 2016 11:55 pm

My only advice is that you'd be better off to set fire to it than to let a dealership do anything more than an oil change, and even that, they will overfill the engine, and strip out the aluminum oil pan/plug...

flman · **Posted:** Thu May 19, 2016 5:59 pm

The cold one minute test is not as conclusive as pulling the cap the next morning to see if you have pressure. The gasket my not leak until the engine has heated up and had a hard run. If any thing after an overnight cool down from the day before driving you should have no pressure or slight vacuum. Pull your cap 1st thing in the morning and see if you are pressurized.

Head gasket or coolant problem?

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