Overheating for about a year now

My 89 XJ is my second vehicle and I rarely drive it. Ever since dish soap was put in the cooling system to try and flush it (dont ask) it has had an issue with overheating. If it's just idling it wont overheat, but if I drive down the highway or 4wheel it (medium to high revs) it will go to 235 (or higher) and I have to shut it off only for it to get even hotter while off, so I crank it back up to recirculate the coolant.

I have replaced the thermostat, removed the thermostat completely after it stuck open (I assume due to heat), flushed the system with prestone super cleaner, held a pressure washer hose in all the coolant inlets and bled the cooling system by loosening the coolant temp sensor on the firewall side of the head while the nose of the jeep was pointed down hill (done this many times). Could I be bleeding it wrong?

My next step was to just buy a new radiator. Here are the two from rockauto:

SPECTRA PREMIUM Part # CU78 {#78} 1 Row; Copper/Plastic

$77.79

VISTA-PRO Part # 432268 {#78, 9178, 99178} 1 Row; Plastic Tank, Aluminum Core, 31"x11.125"x1.5"
Ready Rad; Fits w/o AC; w/H.D. Cooling; w/AC; w/MAX Cooling
$93.79

If buying a new radiator is a good next step, would one of those two work fine or should I get one with more rows or even convert to a newer style cooling system with an actual radiator cap? I have very limited funds to work with, which is one reason I've put off getting a radiator for so long. So I'm looking for the cheapest solution possible as the jeep needs tons of other maintenance related things as well. :explosion

Get a two row.
When the radiator is partially clogged, one tip off is, the inlet hose gets rock hard when the engine is running at moderate to higher RPM's.
Check your outlet hose, make sure it has a spring in it, or is the non collapsible type.
You can actually see the deposits clogging a radiator with a dental mirror and a good flashlight. It is more often worse near the outlet in my experience.
Cheap radiators are to be avoided IMO, you never really know what you are getting. Where I am, I often have to take what I can get, I've had at least two spring leaks within weeks of installation. IMO pay a little more and get a brand name and a guarantee.

Do yourself a favor and rent a test kit from your local parts house and check the coolant for exhaust gasses before you start replacing parts. You must have the same coolant in your radiator for a week or so for the test to work. If you fail the test you have a cracked head or blown headgasket. I replaced everything trying to figure out why it would overheat going up hills and it turned out to be a cracked head.

Thanks for the help guys, I will heed all advice and test with a cooling system tester if I can find one to rent.

Ulver44 said:

Thanks for the help guys, I will heed all advice and test with a cooling system tester if I can find one to rent.

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I know Autozone has the tester, all the way up on the top shelp, usually.

i didnt see it posted but have you tried replacing the mechanical fan clutch.

Don't buy a radiator with plastic side tanks. These are guaranteed to fail when the plastic gets brittle due to thermal cycling.

Strange, but I've never had one fail (radiator with plastic side tanks). Doesn't mean they haven't, can't or won't but I'm curious what their guaranteed point of failure is.

Pelican said:

Strange, but I've never had one fail (radiator with plastic side tanks). Doesn't mean they haven't, can't or won't but I'm curious what their guaranteed point of failure is.

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Most that I have seen fail, failed where the cross passages connect to the metal end plate that is mounted to the plastic tank. Second most common was a cross passage that split at the seams. Most other failures were punctures of some sort.
i saw one transmission cooler, in radiator heat exchanger, melt through the side of a plastic tank shortly before the tranny had a catastrophic failure.
Saw one radiator leak where the plastic tank and the cross passage end plate leaked at the gasket.

First off check shipping on Rockauto!(Rocks shipping was sky high on many parts listed as cheaper, like 120.00 shipping on a rear bumper that Quadratech shipped for 16.00!)
Advance Auto got me an all copper/brass 2 row for a better deal than paying shipping and it has a lifetime warranty for my 89.
Check your temp sender on the back of the head, mine gave a wrong "much higher than normal" reading to the gauge making me think it was still overheating.
Team Cherokee had all the crazy hoses and tubes to the plastic tank and heater. (Replace the tank and the black cap as the cap can give you fits if not in very good condition) Get the mix of antifreeze at exactly 50/50 also.

I'd avoid that spectra radiator. About a third of the ones we've got at the shop I work at have been so far out of square that they can't be installed.

As far as plastic vs all metal, A good radiator is a good radiator and a cheap radiator will leak. Brass/copper radiators aren't like they used to be, the cheap ones are almost guaranteed to leak at the solder joints because they're all using nontoxic solder these days, cheap plastic tank radiators are equally useless.

Bottom line? Most any quality radiators will leak in a maximum of 10 to 15 years of service regardless of construction. The only kind I've ever seen which really hold up are the welded all aluminum radiators, and they're stupid expensive. And hell, most radiators will plug up in 10 or 15 years anyways.

And careful with the block tester. Make sure to drain some coolant out so you're just testing the gasses and not sucking coolant into the smurf blood. Good luck!