bees

Hi everyone. I recently purchased a 99 LS400. After noticing some overheating issues, I first tried addressing the problem by flushing and properly refilling the coolant system. There are a couple problems I need help with.
One, I notice that I have no fluids coming out of one of the drain plugs (please see photo for reference).
Two, after I was finished draining the system, I tried refilling the system from the reservoir but I notice no drop in the water level. After removing the reservoir to clean, I notice there were lots of glitter, chunks of pebbles, and grim in the reservoir (I'm guessing previous owner used multiple types of Stop Leaks). The bottom hose (I'm guessing inlet hose) that goes to the water pump/thermostat (please see picture for reference) was clogged with the gunk.
There seems to be a new radiator replaced and I've tried following a tutorial (http://www.lexls.com/tutorials/cooling/coolant.html) using the Prestone's Flush kit to clear up the clogs, but nothing so far.
Is there another way/approach to this? I want to be able to refill my coolant from the reservoir and not my top bleeder valve. Thank you, your help is much appreciated!!

PureDrifter

iTrader: (10)

if you dont fill it from the bleeder you WILL have air in the system...

RA40

iTrader: (6)

Ouch. As you probably suspect with the grime and coolant contamination, this may not be a simple drain routine.

How much fluid did you recover on your initial drain? The drain ***** are small so any particulate matter that is larger will not get removed from the system easily. You may have to remove the lower hose to drain the gunk in the radiator. Did the thermostat have any reside stuck on it?

Best suggestion from me is remove the lower rad hose, drain (Recover coolant of course.), new thermostat (You probably already did this) and refill system. Run it to cycle the coolant through for a week. Drain again from the lower hose and inspect fluid.

I dunno about the power flush of the cooling system that is available.

GL. I detest the stop leak/sealant stuff, just band aid for problems that invariably become worse.

sethjon

Pure Drifter, I think this is the first time I have disagreed with you. If you fill from the over flow and let it run the air will work its way out. In fact, I recenly did mine and it was fine. I should also saythat I kept the RPM at about 1800 for 2-3 minutes and it immediately burped itself.

PureDrifter

iTrader: (10)

i've done it 3 times on my '99 LS. (an once on someone else's '00) it always leaves a bubble somewhere in the system that invariably gets stuck in either the heater matrix/valve, the thermostat housing, or the water pump (causing cavitation until you rev the motor a bit, dislodging the bubble).

OP: sounds like you need to have a pro take the overflow lines out and properly flush the whole system out.

deanshark

I guess there's a first time for everything. But...I do agree with PD on this. (from much experience) Although I have a 93, it's the same procedure. I've done a drain and fill on mine 4 times and I tried filling through the resevoir once and had to keep adding fluid every day for a week and still had air bubbles. When I used the bleeder, the other 3 times, it was full and bled all in one shot.

bees

Actually, I meant I wanna be able to top off coolant from the reservoir. As of now, the coolant I add into the reservoir does not cycle into the coolant system. I do think I need professional help..

RA40

iTrader: (6)

If it isn't drawing fluid from the reservoir, that is a lot of coolant that isn't cycling through the motor.

Are you are getting any coolant flow?
When did it begin overheating?
How long does it take from cold motor to get past the mid temp mark?
When was the timing belt service done?

LiCelsior

iTrader: (32)

i usually just fill from my overflow then run the car on jacks in the front to bleed it.

bees

I first noticed the overheating when I had the car idling at a drive thru. I'm pretty sure the coolant is circulating as I am able to use my heater and both hoses do get hot. And I think it warms up normally as it takes about 4-5 mins to warm up to the mid line (is it normal for the temp to go slightly above the mid line?). Previous owner said he swapped out the water pump at ~100k. It is now at ~158k.

waseem3000

The 98 normal temp is the two boxes from bottom and 1/4 of the third box and below midline basically and mine, my friends, my brothers do that and definitely there is not enough coolant inside as the hoses get hot but possibly there is still blockage and restricting water flow and thereby heating the car or a plugged thermostat and in your case gunk in the tubings and engine.

The coolant in total needed for this is around 11 liters which can be half water and half coolant as in UAE it is damn hot outside and cold is like 15 degrees centigrade but probably you need all coolant if in colder climates. But the amount give or take is same. So check on it. Hope this helps

sethjon

I thought if you fill from the tank and let it run the air will be purged out. I have a 2000 and did it that way.

PureDrifter

iTrader: (10)

very hit or miss, only 100% way (and recco'd by both the service manual and every tech i've ever talked to) is via the bleeder.

Sherl

I would leave this link here
https://zinref.ru/avtomobili/Lexus/2...nglish/100.htm

Coolant Drain Union is all what you are looking for. In my 98 its right after the engine mount.

kambam3627

Can someone post a pic of this “bleeder” I hear all about it on other posts but you old fellas just don’t like to post pics it seems..... 🤣 I always just fill from the res tank and run the car.