i too have a similar problem where the engine is ticking when hot only. Will changing the thermostat help if so what temp should i use. I live in hot south Florida and it's a 99 disco 1. thanks

 

Put in Barrs leaks.
I ran that stuff for a year before I replaced the head gaskets on the discovery I.
Bought me time and courage.

 

not sure I've got anything goin' on with head gaskets now... hose from the expansion tank to the manifold had a slice in it and blew up... replaced that and just got a new 180 degree thermostat, gonna flush the radiator and put in the new stat and hope for the best....

 

I know its early but could you post if the new t stat helped with the tick. I have a very similar issue on a 99 D1

 

feeling a little less terrified today, took it a bit longer drive (10 mins or so... I live on an island, so that's about as far as you can go without committing to a 30 minute round trip) to borrow an IR thermometer to test the radiator. Air temp today, 89 degrees. Ultragauge held steady at 194 at 30 mph for a few minutes, then steady at 197 for a few more minutes at 50 mph, then 202 back down to 30 mph for a few then levelled off at 204 for the remainder of the trip (obvious slight rises at the two stop lights which I hit twice each... each rise proportionate to cruising temp rise) With ultragauge temp reading of 196, IR thermometer readings taken from the inside of the engine bay, behind the radiator from similar distance (behind all the thermostat hoses... approx 12") showed 129 at the bottom, 155 at the top, which leads me in the direction of a clogged radiator. Felt thermostat hoses once I shut it down and all felt pretty hot... might also be a suspect thermostat, since the lower hose should typically be noticeably cooler... it is not.

Coolant level consistent with level at start and no coolant smell, smoke, engine lights, waterfall sounds or notice of performance degradation.

Questions.
1. Will a flush have the possibility of clearing this out? (and the RAVE says to flush by running water through the system, but everything I've read here say no go to introducing anything but distilled water)

2. Never used an IR thermometer before and not really sure I did it correctly.

Going to swap out the thermostat anyway with the new LR Original 180 degree stat, but figuring if there's more goin' on, knock it out at the same time.

 

A good cooling system flush is always good. You can start off with a hose but follow it up with distilled water. I have a back-flushing tee spliced into my heater hose and the adapter is made to connect a garden hose. I do that and then pour distilled water directly into the radiator, then directly to the motor on the other side. then fill the system up with distilled water and run the engine for a minute, then drain again. Attach the jet-sprayer to your garden hose and blast the radiator from the inside of the engine bay outward toward the grill. (You must remove the fan and shroud assemblies, but that takes 2 minutes if the nut on the clutch isn't frozen) Look down in front of the radiator while you are at it, you will be able to see all of the dirt/grass/bugs coming out. Be careful not to hit the fins with the sprayer, as you want to be pretty close to take advantage of the pressure. You want to hit 100 percent of it; start at the top, obviously, and get all the way to the edges and then down to the very bottom. Be sure to rinse all of the crap out from behind the grill when finished. Put in a new thermostat, as you proposed, and fan-clutch if you haven't already. If you still have a problem after all of that, go back over the radiator with IR once you have a firm grasp on the parameters of it. I have yet to do it, so I can't tell you anything.

 

swapped the thermostat and flushed the radiator with a hose until it was clear... no evidence of any junk came out. filled with distilled water and bled the system. test drive results as follows.

approx 6 miles - most at 30mph, 1.5 miles at 45. Once up to temp, temp held steady at 189 for the first third of the trip, then to 192.6 for the next third and then 194 for the remainder. Temps did rise accordingly at stop lights and proportionate to cruising temp, with a max of 202. Expansion tank about 1/4 low from full at shutdown, but probably still filling the system and needs to be bled more.

Gonna let it cool down, flush the radiator with distilled water and then refill with coolant to spec (the green stuff) bleed and see what we've got.

Also seems to have quieted down the ticking noise a bit (a buddy heard it start the other day and said it sounded like I had some lifter noise) Also going to change oil again, oversize filter and Rotella 20w50 (did an oil change to rotella T6 when I first got it, having no idea what was in it to start)

sure would be nice if it were that simple (yeah, I know I just jinxed myself)

also noticed that this connector, well, isn't... any ideas what it might be for?

 

That fan should turn on when the AC is running. If it doesn't then that would be the reason.

 

confirmed. fan DOES turn on with A/C

 

drained, flushed with distilled water, filled and bled system (approx 60/40 water to coolant mix with 6 capfulls of water wetter) same drive scenario as listed before, system settled in at 204 constant. Noticed a hairline fracture in the bleed nipple on the tee (oh goodie, more parts to replace. looked around for this... can't figure out what it's called and if I can just get it or do I have to buy the whole hose assembly... hoses look pretty good) I'm leaning toward the radiator being junked up. Gonna hit it with IR thermo again, this time more precisely. With heater blowing good and hot idle temp held at 208 for a few minutes before shutting it off. No sign of leaks, expansion tank down a little less than halfway from full, but again, assuming that has to do with getting it all topped off.

What do you all think?