also "flow tested" the heater core with a garden hose. water passes through very well and clean.

i am afraid that the block might either be cracked or has a hardened blockage from the previous owner using some form of stop leak.

 

Sure sounds like it's down in the block, as I mentioned earlier.

"Stop leak", which you just mentioned, raises red flags to me.

 

i know there is a block drain on the drivers side of the block. do you think i should try running the motor with this drain removed and a garden hose in the filler neck of the radiator?

 

that's all i can think of before i have to pull the motor, tear it down have the block vatted and re-assemble. If i go that far i guess its stroker time.

 

I wonder if they were trying to seal up the head crack?
The Jeep did run at normal temp when you first got it? Didn't start running hot until the first radiator replacement?
If that's the case, I doubt there is a permanent block from whatever stop-leak was added, it would've been hot when you got it- but there might be a clump that broke loose when it was disturbed and is now lodged against something it cannot pass through. Have you tried flushing the block in reverse direction?
Might have to find or borrow an air/water pressure nozzle to blow the block clean if a garden hose isn't doing it.

 

Start there. I had the same cheap *** rad cap, it wasn't my issue but when I went to do the cooling I opened the lever and it released pressure for at least 15 mins, and it came roaring outta there it HAD to be more than the 16 psi it takes to open one. Also explained why when it got warm it never drew any coolant back out of the overflow. It honestly could be your problem. Get a Stant.

Also clean the AC condenser. Its free, other than time. Lol. Even if its not the issue its a good idea. I wouldn't replace it if it works though.

 

explain in detail how you are getting your temp readings.

And do you have an aftermarket guage installed and working somewhere?

 

Interesting mine does the same thing, I will get a Stant cap today.

 

I am utilizing the factory temp sensor via OBDii interface, as well as using a non-contact infrared temp gun (the pistol grip looking one with a laser made by bluepoint). I have been measuring at the thermostat housing, where upper radiator hose meets radiator, where lower radiator hose meets radiator and on the surface of the water pump. there is some variance from location to the next but some components suffer more "heat soak" than others.

The only aftermarket gauge i have is for trans temp, it is digital.

Also forgot to add i also installed hood vents quite some time ago, to help alleviate under hood temps. Also i am using a factory exhaust manifold not a header.

 

Time to rip it and fix it?

 

I'll just throw out a $100 toss up suggestion.....buy a new OE style 1 row (1.25" wide/thick) aluminum/plastic rad. Best I can tell, u've replaced everything with Mopar OE factory style parts except for the radiator.

I do not want to get into a flame throwing contest with others BUT, just give this some thought. That aftermarket 3 row rad is a old school copper/brass design with very narrow tubes (also old school design) with 2 air spaces separating the 3 tubes thus making the actual core thickness virtually the same as the modern design OE style 1 row aluminum/plastic rad. The 3 row core is not 3X as thick but the 3 tubes are substantially narrower than OE modern design .The difference is, the OE style has 1 very wide row that is a more efficient heat dissipating design. New car manufacturers haven't used narrow tube copper/brass rads for 20+ years. Now days, we have 1/2 ton p/u trucks with 10,000 lb tow ratings running 1 row rads.

http://www.stockcarproducts.com/rad2.htm

Again, this is simply a suggestion......at this point, u've spent a grand on new OE Mopar parts, etc. (except for the rad), what's another $100 for new OE style rad as an experiment. If it works, great, if not, sell it.

http://www.stockcarproducts.com/rad2.htm

 

I thought the same thing.

 

I read thru the thread quickly.....if I plagiarized, my bad/apologies.

 

No prob. Just agreeing with you. Lol. Its funny how an "upgrade" isn't always an upgrade.

I'd still check out that rad cap first OP

 

I bought mine and they have just put a new radiator, Mine runs from 210 -220 this is just reading from POS temp gage that is in cluster. I don't have temp gun to see what it really is but would like to find out.