Make sure you don't check that fan clutch while the engine is running. Lol.

Flush your cooling circuits one by one before installing another rad. Youll have the hoses off anyways. Flush the heater core (I pour In Prestone cleaner, pour in hot water, let sit, flush out with either air or a water hose), flush block (cap off the lower hose outlet from water pump, pour hot water/prestone, flush out through tstat housing with hose after removing water pump block), flush 'new' radiator in a similiar fashion. I'd put a new tstat in (go OEM, trust me). Verify fan clutch operation. Also verify temp readings anyway possible (knab a used sensor from the junk yard and clean it up to see if there is a delta in temp readings at gauge). Git'er'done.

 

I went through a major over-heating issue a couple of years ago with a 94 XJ. I replaced everything except the radiator, but I took it to radiator shop to flush and check it, and they said it was good. It was an aftermarket aluminum 3 core I put in.

After replacing everything that coolant runs through, including rebuilding the head, it turns out it was the radiator after all. The reputable shop I used was full of crap, or just didn't test it.

 

I pulled the radiator out and flushed it, and im going to solder (sp?) The hole shut like I should of done in the first place. Then im going to attempt to flush everything else before I put it back in.

 

Remember! One component at a time! Heater core/Block/Radiator.

Also, bunk my t-stat recommendation. Only replace it if it is old and you want to do it to flush the block properly. I just saw the 'upper hose gets hard and hot' a bit ago.

 

Be more concerned about wasting your money on a used radiator. That's not money well spent.


Yep.



All that work and money to get everything else right and you want to skimp on the t-stat?

Makes no sense to me. It's a cheap part and an easy replacement. Too much risk for too little benefit.

 

Neglected crossflow rads have a tendency to fill from the bottom up with solid crud/scale. The top half of the rad can still be clean and flow freely and the bottom half not at all. Considering how small the XJ rad is, having only half a rad is not good. A garden hose will not remove solid crud/scale build-up. The only way to internally inspect/clean the XJ rad is to separate the tanks from the core. A JY rad is a gamble at best.

 

I flushed the heater core, block and radiator separately, and fixed the radiator. Put it back in and put some water in and gasoline and it stayed right at 210 and is running great. I drove it around some and even down a trail on my property. Tomarrow im going to flush it a few more times and put all new antifreeze and water in it just In case.

Thank you all for everything. I hope this thread helps somebody else track down cooling issues. Yall are what make this forum so great. Yall helped me get my baby back up and running.

 

Good to hear you have it up and running,