Hey guys!! First I'd like to thank EVERYONE for the amazing content and help I've found on this site. I go by A.J. and I live in Las Vegas, NV. I've been lurking for a few weeks now (since I decided i wanted a disco 1) and decided to join the ranks. I ended up with a 1997 Discovery. She loves to over heat and enjoys watching me stay home instead of playing outside....only for now! Hopefully there might be some fellow Las Vegans that would like to meet up once I get her running cool. Once again, hello and thank you!

 

Welcome. First up, a 180F stat. Second, like my old one, your radiator may have calcium build up. Find an indy rad shop that does construction equipment. Near me such a shop charged $75 for rod out and hot citric acid flush.

 

Savannah Buzz, I've been following every single one of your posts and advice. So thanks for pointing me in the right direction! I've done 180 stat, fan clutch (confirmed bad), water pump (rotted impeller), headgasket coolant gas test (negative), backflushed radiator (lot of crap came out, now running clear, and now currently doing a poor man's CLR/hot water soal overnight to see if I can get closer. Before radiator pull I had it idling ~180-190*f at idle but it still went to 215-225*f after driving for 10-15mins (per scan tool live data). Bled as best as I could but would still get boiling once I let expansion tank cap loose. Anyways thanks for all the advice so far and feel free to slap me around with any ideas! I considered PMing you but need to wait 10 days =). Thanks for the welcome! Can't wait to get out there with with!

 

I tried a variety of soak at home methods, including brick washing acid. For me with a 97 it was the trip to the rad shop that made the difference. One way to eval radiator is warm up truck, engine off, and use IR thermometer to measure temp on fins. Should be under 10F change top to bottom. Lower rows clogged up will be much cooler, because of low or no flow. Water flows from driver side (US) in parallel across all tubes. My D1 had about 5 degree spread.

I bleed by putting battery side of truck up a steep incline or curb, and take off that fitting on top of radiator, run at fast idle for several minutes.

If you are hearing gurgles under the dash there are bubbles in the coling system. If your thermostat does not have a small bleed hole or jiggle device those biubbles can become trapped as a steam pocket.

And since you have gotten technical, we'll move all of this over to the D1 section.

 

X2 on savannas suggestions. Any codes? Hearing water sloshing behind dash? if yes you may need to burb the system.
Check for clogged PCV hoses and check your oil separator on the passenger side rocker cover. Be sure you have the tan expansion tank (not the black on) the black ones are ticking time bombs and need to be switched out. My radiator was so badly clogged I had to replace it. You get what you pay for in new radiators. I went with a OEM style nissens radiator ($500). Would be good to check out your condenser fans for correct function. They should kick on at 215 I think without the a/c on. With the a/c on both fans should kick on and run full time. 215 is still too hot for these tractors. I wouldn't drive your truck very much at all if temps are not below 210 to avoid cooking your motor and Hgs. normal range with a 180 tstat is 177-210 max.

 

Thank you guys for the direction! This will be a slightly lengthy post, hoping it may help others.

After letting the radiator soak in CLR last night I made sure to flush and blow it out as best as possible before reinstalling. I have the truck currently running at 180-192* idle (letting it warm up from a cold start). Once I start driving the idle is 198-202*F. This is in a 101*f ambient/outside temp. I did have it up to 210*F after driving freeway speeds then coming to a stop. It cooled down to ~202*F after sitting for a minute. Is this going in the right direction?

2nd part of the story: Before pulling the rad for CLR flush I was having the top radiator hose pressurize harder than I'm used to seeing. During reinstallation of hose I noticed there was a small pinhole leak (suction). It was weird in the sense that it would not leak coolant out when system was under pressure or during a pressure test, but would make a suction sound when the vehicle was started from dead cold. I figure this caused air to get sucked into the system, which turned into a giant steam pocket pressurizing the hose once the thermostat opened. I replaced the hose earlier today and noticed the vehicle ran cooler under load and the new hose was not as bloated, but was still firm. Is this normal? No air bubbles coming up in the expansion tank and the heat is operating perfectly. I don't hear any sloshing behind the dash.

Question about the bleed. I understand you leave the top radiator plug off until the bubbles are gone and only coolant is streaming out while the vehicle is running (thermostat open) correct? The only "bleed" i've done is to leave the radiator plug open while cold and lift the expansion tank as high as possible, then reinstall the plug once only coolant / no bubbles stream from the hole.

Again, you guys are great! If anyone is in my area...i definitely owe you a beer!!

EDIT: Took it for another drive. Coolant system is building up too much pressure and top radiator hose gets rock hard. Temp did go up to ~215*F for awhile. Hopefully not head gaskets, though I'm not sure why it wouldn't show up on the fluid test =(

 

fluid test shows exhaust gas in coolant, not steam. Steam makes the hose hard. Can be from too hot system, cracked engine block or head, etc.

 

Get a new expansion cap. 15 bucks and a good place yo start. Might not be bleeding off pressure as it should.

 

I haven't done that. Anyway to check the expansion tank cap? It just seems too easy

 

The hoses should be more firm under pressure then without, pressure on the system allows the coolant to go hotter without boiling,

I did coolant cap, hoses,stat, pump,had Rad rodded, fan clutch, Saudi grill, finally head gaskets then the fan clutch was bad again