I know this question gets asked many times but after reading multiple old threads I just want to make sure I got this right

Background
So had my disco for about 2 years and it has always gotten a little hot while sitting idle with AC on. Last year I put a new themostat in it (motorad) and did bring driving temps down but idle issue still there. Then found leak on upper radiator hose and replaced it. Also noticed the front condensor fan not working so replaced it. The hot season passed and didn't think to much of it at that point thinking I had it covered. Its one of those things I don't drive the car much and rarely does it have to sit idle for more than a few minutes at a stop light.


Forward to this year. Once it got warm outside again I noticed the same issues. Viscous fan I knew might be an issue but hand test it seemed to pass. Ordered a OE thermostat thinking the issue with the motorad may have something to do with it and decided to flush the system as well. I saw mentions of some DIY methods with baking soda detergent and decided to try that. My house was done at that point so had a garage, drained all the old crap out, refilled with water and added a cup or so of the detergent and drove it on a test drive with no issues. Next day I get into it and within a mile the temps spiked and I got it off the road but I did reach somewhere in the 230-240 range (scary). I know at this point I may have cause more issues. I was assuming the detergent caused a clog but after it cooled off I was actually able to drive it home with no issues again

Reflushed the system with 50/50 mix, and replaced thermostat at this time. Temps while driving actually were down about 10 degress (185 from 194) but at idle with AC it would still creep up. I tried doing IR readings on the radiator but my numbers seems all over the place so not even sure I was getting good readings. Then found the small connector on the radiator was actually busted and had been siliconed back into place from previous owner and was leaking.

Decided to go ahead and order and replace the radiator, clutch fan, water pump, overflow cap, and cleaned the condenser fan out. All that had been replaced as of this weekend. Still issue at idle with AC on. Seems to stay steady at about 190-194 with AC off. I will say all this slowed down how long it takes but its still creeping and I have let it get to 215 or so. I can rev the motor to about 1250 and the temps will actually drop or I can turn on the heater and the temps with drop as well

OK background done

So one possibility is I have air in system, which I have been trying to bleed out. I am using the RAVE procedure of raising the overflow, upper hose is propped up on cowling, and removing bleed screw all while car is cool. When I remove the bleed screw I am hearing a good amount of air escape. I am running it between bleeds and have tried with ac on and heater on and letting it cooled off between cycles and getting air hiss every time. Either I have a lot of air in there or something is letting air in (i.e. HG). Since I have replaced everything I have probably on bleed it the initial bleed and one other time so still a good chance its just got normal air trapped still

Another possibility is I am still somehow not pulling enough air out of radiator. New fan clutch could be bad but after car is warmed up it only turns about 1/4 turn smoothly (old clutch felt the same). I posted about my PS pulley having a little resistance and play to it. Is it possibly their is enough resistance that the fan isnt spinning fast enough? I know that is out there but was just another thought. I would think that would cause other issues as well though (low voltage, weird steering issues) which I don't have any. Belt is routed correctly and condenser fan is pushing air the right way as well

Rented a coolant pressure tester from Oreillys only for it not to fit but sounds like the one from Autozone does. I am guessing this is my next step and sound like get it to about 18# and let it sit for a few hours to see if drop.

My questions are this. I am on the right track and what steps do i take passed that. I don't think I am loosing coolant but not positive with the way bleeding is going. I don't see any signs of coolant leaking out and oil looks good as well.

Going to take a harder look for leaks during pressure test (my throttle body has already been bypassed as well) to see if its just not making it to the ground. Passed that it sounds like I may just start pulling the heads from it and taking a look to how things look. I have the tools and the car isnt used much so this wouldnt be to big a deal. I have already been reading on what all i should replace while in there and getting a list together if this is the case

Reading other post has me a little worried about a cracked blocked (or slipped liners). I will say I don't have any abnormal engine noise and car runs pretty well. Once again sorry for another post on this topic but for peace of mind wanted to see what others think. I bought the car with 122k on it and wasn't sure if HG job has been done in the past or not. Now at about 132k on it I am sure its well past their time if they haven't been replaced yet.

 

while pressure testing your system shake and pull on every hose you can reach while under pressure. if all that checks out OK.

the problem does not occur unless the AC is on basically is what your say?
it looks like your temps are normal until the ac is turn on. (the compressor cycles on and off all day)
have you had you AC system checked to see if it is over charged?

it would be rare that the few btu that the a/c system running normally tax your cooling system so much.
that is the purpose of the condenser fans.

 

Good call on the ac, didn't even think about it being overcharged. But yes issues seems to only be there with AC on

Driving temps are 180 to 188 usually (AC or no AC)
Idle temps with no AC are 194ish
Idle temps with AC will creep up to 215+ I usually just shut off the AC or car at about 210 anymore now that I am keeping an eye on it

My other thought is the condenser fan I bought just doesn't push enough air. The one I got is VDO PM9116 Condenser Fan Motor. Been trying to find any specs on it with no luck but I see it mentioned in plenty of threads as the replacement

 

once moving down the road the fresh air will over take the fans, but it only happens at idle or in traffic then i would look at the condenser fan.

 

Making some progress. With coolant pressure test at 18# I found 2 leaks on the hoses that attach by the bleeder screw T. That piece is maybe a year old and had the snap on clamps. Put in the screw on type and leak was stopped. Then found slow leak on the modified throttle body bypass clamp and got it tightened.

I will say that slowed down how fast it starts to get hot considerably but after 5 to 10 minutes of sitting still the car will eventually work itself to 205-210 in temps with AC on. I assume maybe with AC off the car might eventually get hot but I dont notice it happening but I also wasnt going to just sit there for 30 minutes with it running to check

I see some what looks like fresh fluid on the backside of engine, top of transmission but from the top cant tell where its coming from. Not even sure it coolant but will check that out more tonight. At 18# of pressure after fixing those leaks I am dropping to about 17# after an hour or so. That means I have a leak somewhere but pretty minor. I put it at 16# this morning so curious to see where it is at after 8 hours at work. I am assuming I have the start of a head gasket leak at the back of the motor that I need to start planning for replacing. I changed my oil last night and it has no signs of anything mixing in it so that's a good sign.

 

yup, still have small leak somewhere. may not be head gasket you will be surprised where you can find a leak with a pressure tester.

look any place coolant can hit a manifold and boil off, the weep hole on the water pump,
under the recovery tank.

if all else fails line the bottom of your truck with newspaper and test it overnight, i find that newspaper will attract water from miles away.

 

So guess I will get AC checked to be sure but after re-bleeding system I was able to hold 16# for 10+ hours and went up to 18# for 2+ hours with no drop. Could be that only leaks if motor gets hot I suppose but going to get AC checked to be sure. I rechecked everything is working, as in viscous fan will not spin but 1/4 turn by hand, condenser fan is on and blowing right way, and as said radiator and water pump are new. I have had same symptoms with 2 thermostats as well. Its does take it 10+ minutes to get 200 but continues to climb to at least 210 before I shut it down.

 

When you say OE Thermostat do you mean the stock D2 stat?

If so your temps sound in the correct range...

Or do you mean that you installed the OE TD5 180° stat and you are still having these temps?

I tried to see how much temp change turning my AC off made and it didn't make any diff at all. I have the 180° TD5 stat. Idles around 197.

I had temps like you describe when my mechanic put in a Motorad 98°c stat. That I believe is the stock replacement but I did not like how it got into the 220 range when long idling.

 

Sorry I should have explained that better. I had a Motorad 180 tstat in there for about a year. It ran about 194 on the highway but saw it go above 220 at idle. I just put in a 180 Genuine LR stat and highway temps are down to 185ish but have same issue with it getting hot at idle with AC. Going to start by checking if maybe previous owner had AC overcharged. The AC seems to work good and has the two years I have owned the car.

Without using AC the car still gets to 197 but stops about there. I tried to bleed system again and doesnt seem to be anymore air coming out and I am not losing coolant but this is a sample just of the last week.