xjallseasons

I recently ran into an issue with my motor where I believe I have a cracked head. There's only 155k on the 1996. The owners (the reason why I that is plural is b/c I am the 3rd owner and am not sure which one started this issue) put some additive to the coolant probably to seal any cracks in the system. The issue for me is trying to get rid of all that sludge that is clogging my system. It's getting worse and worse. I used to be able to drive it all over now I can only make it about 3 miles before I start to overheat. I believe my engine has been cooked a few times as I have done it once or twice and who knows how many times before that. I dont have any issues with it starting, it runs great just not for long periods.

So my questions are how do I remove this clogging issue? I have already replaced everything in the cooling dept and the clogging got worse, so I know I have replace everything again plus its been a few years. I believe I have to remove my dash to get to the heater core and replace that since I am sure that is clogged as well. I already bought a new radiator. Are there any additives that will fully remove the sludge without having to pull the dash to get to the heater core?

Then there's the issue that the block could be cracked as well. I know that fixing the above problem wont fix any of the cracks (if there are any) in the engine, but how do I know unless I have it completely checked out? How do you have it checked out?

Well this leads to my next question - if there isnt an additive that can fully remove the clogging issue, then I will have to pull the dash, replace everything in the cooling system and possibly pull the motor to have it steam cleaned, right? I know all this could be very costly but what options do I have except for what I have listed above?

I have considered that if the motor has to be pulled to steam clean the areas where the coolant flows (mostly along the length of the block), then since its out do an overhaul and assess what needs to be done from there. I have considered building a stroker but at what cost? Should I just buy a stroker motor and use mine as a core? Or should I use mine for the build?

I have a friend/mechanic who will help me with the labor but I am taking away from his time and getting him to get away isnt all that easy. This could take a month if I am lucky but I am prepared to doing so.

PatHenry

Have you tried a --thorough-- flushing of the cooling system??

If not, I would start there. Get some Prestone flush, probably 2 or 3, 12-15 gallons of distilled water and flush the system and flush it again. Get your garden hose and run it through the heater core on both sides, disconnect the radiator hoses and run the hose through both sides (when the engine is cool). Empty the radiator between flushes via the lower hose. Repeat process at least 2 times.

In the meanwhile, send an oil sample to Blackstone labs and get an analysis done - that will tell you if you have any foreign contaminants in the oil (a sign of a cracked head or block) and do the exhaust gasses test in your coolant. (You can get the tool as a loaner tool from your local retailer and buy the test chemical at the same time.)

Given what you've said, it's most probable that you have a clogged up radiator that is causing the overheating. However, you need to get all that gunk out of the block, heater core (if possible) and hoses before you ruin your new radiator by installing it prior to cleaning it out. I would certainly not jump the gun and assume it's a cracked block or head without doing the most basic diagnostics first.

Jeepwalker

If you can put a hose to the radiator with hot water that would be a good first step. Just let it drain out. If you don't mind spending a few bucks, you could call a radiator shop and ask what they charge to 'boil it out' ..essentially clean it in a caustic solution. They usually look like new afterwards. Before removing the heater core I would consider doing a flush on it. Remove the heater hoses from the heater core and do a reverse flush: Put a garden hose with hot water (let it lay out in the sun for 30 min) ..and blow with full water pressure the opposite direction of normal coolant flow. You'll be surprised how much crap can come out!

Flush the engine ...maybe bypass the heater core temporarily after you've manually flushed it, temporarily, and re-flush the motor after a couple weeks of driving. Then put purified water or a 50/50 pre-mix of coolant in it once all the repair work is complete.

xjallseasons

Yea, I have done this before a few times thinking I would dislodge something. I have flushed all the lines, replaced the lines, water pump, t-stat, and radiator but never the heater core. I havent ever gotten to the heater core. I know how much of a pain in the *** that can be. I have even gotten a power washer and cleaned the best I could to get it all out. It worked for a few years, until I had to do it again and again. Im fed up and want it fixed.

Jimbo Slice

Have you replaced the water pump and thermostat?

xjallseasons

You didnt read my last post. Yes, everything that has to do with the cooling system has at one time been replaced. I have since bought a new 3 row alum radiator, new cap, new hoses, new t-stat and water pump. All that is left is to pull the dash and replace the heater core.

EZEARL

Why not just bypass the h/c and see what you get.

awg

I would pay ~$40 to have your oil or coolant anaylised for cross contamination, as the most certain, cheapest and quickest way to confirm any crack or failed gasket

To clean out engines, I have had success with repeated use of ordinary dishwasher tablets

lawsoncl

Do you get good heat from the hvac? If you do, I wouldn't worry about the heater core other than a flush. Did you use a stock water pump and thermostat cover, as a few folks have reported that the hi-flow versions actually made things worse. Also, have you replaced the fan clutch? Fan shroud, etc intact? Any check engine codes, or other reason to believe you're running lean? If it's an automatic, is the tranny slipping, as can dump a bunch of heat into the radiator as well.

xjallseasons

I don't believe I'm running lean and everything is in good running order, nothing's broken. I do have a crack in my exhaust manifold but everyone knows these run hot and don't think this is my problem. And the oil filter manifold is leaking but it's probably the gasket.
My check engine light isn't on. As I said before this engine runs great. The heater works great, the trans doesn't slip, i even have an external trans cooler.
Here is a pic of my radiator and cap.

Thick, peanut butter consistency paste.

EZEARL

Heck of a mess!

First off just because your CEL light isn't on doesn't mean there are no fault codes tripped. Accessing with your key can only show so much. Unless certain criteria are met that the computer monitors the CEL won't come on. If you haven't had it scanned you may want to do so. No doubt a cracked exhaust manifold can cause too lean condition by affecting the upstream O2 sensor.

As far as the restricted coolant passages in the engine there are extreme measures you can take to clean them out. Google "How to remove Barr's and Stop Leak from the engine".

lawsoncl

Wow that picture is nasty. It's either a crapload of stop-leak still in the system, or the coolant is going bad. The new dexcool crap can turn brown and gooey if mixed with the old green stuff or due to a head gasket leak. Definitely figure out if you have a head gasket leak, and I think you're looking at a ton of aggressive flushing to get that goop out. Once you get it clean, only use the old-style green stuff.

third coast

Go back and reread advice in post #2 from PatHenry. Do a combustion gas test at the radiator cap. Follow directions to drain a bit of coolant down to prevent it from getting into the tester. This will help determine if the head is cracked or a head gasket is bad. Oil analysis from Blackstone Labs will give you data that tells you a lot about the health of the engine and if coolant is in the oil (which causes excessive engine wear).

My opinion is NEVER use stop leak stuff. It is not a “fix” and it presents other issues.

awg

one of my XJ came to me like that..swamp mud for coolant. I purged the cooling system, added fresh water and a dishwasher tab...10 times in a row..until the coolant stayed fairly clear, then added 50/50 glycol mix...subsequently had to change the radiator out anyway

xjallseasons

Wow. A plethora of great advice. Now I just have deal with this Phoenix heat to get the work done.