Saw a new listing on a pull a part junk yard website for 98 Disco - decided to go the next day (Mistake #1 - big yards with on-line vehicle listings also send out emails to people looking for specific range of vehicles - by the time I got there it was picked over).

Looked at the radiator, it had a 2005 date sticker. Had new fan, and shroud and front grille had been replaced. Had new looking heads (probably a cylinder head shop high quality job). Vehicle had been garage kept, paint was great. Removed radiator top plug and looked inside with flashlight, no calcium build up on tubes that I could see. (Mistake #2 - why was a 170K vehicle in this shape at the boneyeard?)

Pulled radiator ($37), included the upper and lower hoses (nice condition - will carry as spares). Tranny fluid ran out, green o rings in place, coolant ran out (radiator holds water), oil ran out of cooler fittings when removed. (Mistake #3 - should have carried short piece of clean hose to blow thru coolers - before leaving yard)

Reverse flushed for 1 hour. Installed in my 97 Disco. My original radiator is at the shop to be rodded out. Figured I could now use it as a spare. (Mistake #4 - did not use solvent to clean out the two coolers)

Cranked Disco by reaching inside, I was too dirty to sit on the seat. Had already plugged in scanner. Checked for leaks, all good. Scanner came up to 185 degrees, then my 180 stat opened and it settled back to 175. I had left coolant tank cap off to burp, and had heater on full, no AC. But heat was strangely cool. (Mistake #5 - I failed to check dash after crank up. Yikes! The oil light was still on!!!)

Shut down, checked oil pressure switch - removed wire - light went out. Had no prior problem with oil light. Checked shop manual - the top oil line on the radiator is the return path. Cracked that fitting open, cranked up, expecting a gush of oil that would tell me I needed to replace the $8 pressure switch. No oil gush.

Removed both oil lines from radiator, small quantity of oil ran out. Tried to spray solvent. Nothing came through. Used air line to try to blow back, nothing. Used oil vac pump to pull out something from the lower port, but still blocked 95%. What came out looked like calcium (white, gritty), not oil sludge.

With oil cooler blocked, that extra heat load was not present, so radiator was cooler (heat was not up to par). It would not have remained that way, of course. Since previous owner of the radiator had done the heads in his vehicle, it is possible he used stop leak leading up to that. The radiator may have had a small leak to the oil cooler, and stop leak may have begun to close down the oil cooler. No matter the original cause, the effect of a restricted oil cooler is to kill the engine.

Not sure how often Disco's have oil coolers that get restricted. Any comments on using a remote oil cooler in place of the radiator version?

 

You do not need a oil cooler.
You should beable to blank off the oil ports on the engine, the DII does not have a oil cooler.
I think a solvent is the only way to clean it out.

 

Like Spike says, you could cap it off or you could just as well add an aftermarket separate oil cooler and mount it it behind the grille in front of the rad.