keyfig

I have a 1996 ls400 with 145,000 miles on it. I noticed last winter the heater would blow cold air when idling at a stoplight. As soon as you take off, it would blow warm air. Also, during the summer I noticed the engine would run warm to hot when idling. The heater core valve will open when the heater is on but it seems there just isn't enough oomph to get the coolant circulating through it. I am assuming the two are related. My mechanic cleaned the throttle body which seemed to help for a short while. Now the problem is occurring more often. When it starts to get warm, in the past I just had to rev the engine to force the coolant to circulate, now it takes a while to get the temp to come back down. Any suggestions would be helpful.

Raddison

Welcome to CL, the search bar can be found near the top of the screen.

There have been multiple threads on similar problems over the past month or so.

PureDrifter

iTrader: (10)

air bubble in the coolant and/or faulty thermostat.

as raddison said, search.

deanshark

If it's cold at idle that would point to air in the coolant system. That happened with mine, and many other members, and bleeding the system took care of it. One tiny air bubble can make a big difference. The temp gauge going up at idle points to air, not enough coolant, and/or thermostat not opening enough. When you raise the RPMs it pushes the coolant through faster which cools it down. My suggestion would be have the coolant flushed and make sure it's completely filled afterwards and bled out correctly. A T-stat only cost about $20 so ya might want to change it anyway just to be on the safe side.

I noticed you also posted this in the NELOC section but this LS400 forum is the best and quickest way to get your answers. (other then searching) Welcome to CL and as eveyone will tell you, the search feature is your best friend.

fishguy55

Please teach a new member how to search JUST the LS 400 section of this great forum. Thanks

deanshark

See at the top of the page where it says SEARCH?Click on it. Type in what you want to know and press search. Or....you can use the advanced search and go to which ever forum you want to look in. Totaly self explanitory. And now it's even surrounded in red to make it even easier.

keyfig

Sorry guys, I know I'm new to this forum but when I tried to do the specific search, I couldn't find a good match for my problem. Anyways, I changed the thermostat and bled the system. It took care of my overheating problem, but I noticed I'm still getting cold air from my heater at idle. Any more suggestions? It doesn't do it constantly, only after idling for awhile.

PureDrifter

iTrader: (10)

you didnt bleed the system with the system at full op temp and the heater on full blast.

deanshark

Couldn't find when you searched? I took the title to this thread, put it in the box next to the white letters surounded in red that says S E A R C H, clicked on the word search and came up with 6 different threads with your exact symptoms. This is one of them and if you look in post #10 you will find 6 more. https://www.clublexus.com/forums/per...hen-drive.html
ALL of them saying "air in system"

For future reference; Whatever you are going to put as a title of a thread, put that in the search box and you'll find your answer 95% of the time.
Like PD said, warm the car up to normal operating temperature, turn the heater on full blast, then bleed the system.
Where are you bleeding it from? The correct place is the 17mm bolt on top of the thermostat housing.

keyfig

Sorry deanshark, we're not all as adept as you are at using this forum. I was under the impression that people were supposed to act in a courteous manner when posting. Not everyone using this forum are insensitive males. Some of us actually are women who try to fix things on our own. Yes, I did bleed the system from the 17mm bolt on top of the thermostat housing. Maybe I need to bleed it some more. After idling the car for at least 15 minutes, at normal operating temp, it seemed to have filled up.

denverdog

putting your thread title in the search box doesn't work if it is "newbie here", or "got a problem", or "hope you can help." so i'll harp on this once again. everyone should put words in their thread titles that mean something in terms of a search. use the part, the system, or the symptom. or all of those. then you can utilize the search function without going through 30 replies only to find out it isn't what you're looking for. you'll also probably get more and better replies to your questions.

PureDrifter

iTrader: (10)

cut it all of you. less drama more relevance please.
OP-you should have searched, now you know.
dean/denver- i'm amazed i'm saying this, but cut the n00b some slack.

keyfig

Sorry guys, I really don't go for all the drama. I appreciate the help and will try to do better on using the search tool in the future. (Already got flak from hubby on my last post)

Raddison

Amen.

Here's a tip for the OP, like.. actual helpful advice, lol.

I just did a coolant flush on my 90 LS, first off all, save yourself the trouble and get everything ahead of time, I'm feeling super helpful, sooo, here's a mini-instructable.

Gather all of these things (seriously, every little thing, they will help so freaking much, my frustration is your gain! ) :

- Ramps or a jack and jack stands (to raise the car)
- 3/8" drive ratchet
- 10, 14 and 17mm sockets
- Duct tape
- A bottle of Prestone super flush
- 6-8' of 3/8" inner diameter clear tubing (a few bucks at menards/home depot)
- Drain pan, a big ol' drain pan
- A sweet LED worklight never hurt
- Eye protection (because no one likes rust in their eyes)
- Pliers
- 2 gallons of ORANGE coolant
- 2 gallons of DISTILLED WATER (to mix with the coolant for the final fill)
- Torque wrench (to feel good knowing you tightened things to spec!)
- 3/8" drive EXTENSIONS (while youre at menards/home depot grab these, you can get a set with a small, medium, and large extension for a few bucks)

That should be all you need, once you have that assembled, give it a twice over while referencing this write-up

http://www.lexls.com/tutorials/cooling/coolant.html

That write-up is almost perfect, except for the fact that the drain **** bolts can be reached head on with extensions.

Make sure you tape the hell out of the tubing onto your drain pan, initially (if you wait for your car to fully cool down) the coolant won't be hot, but after the cycle with the super flush and the following pure water flush, the fluid will be HOT and loosen the tape and then you'll just have a mess.

Once you finish doing your final fill, run the car with the heater on full blast with the a/c on, with the RESERVOIR CAP OFF for a while, let the car get niceeee and warm, the level should keep dropping every now and then, just make sure you keep it topped up as to not suck in air.

When the level stays constant, congrats! you just finished flushing your lex and your engine is happy!



I just realized that this is all over the place, I hope it all makes sense, its 3am and I'm ready to pass out. Someone feel free to copy this and reorganize/reword it.

deanshark

I wasn't trying to be an "insensitive male". I was explaining to you what you asked, how to search. Sorry if you took it in an offensive manner. Just here to help. Sometimes I get too sarcastic and kid around a little with my weird sense of humor, but it's hard to understand that when it's just typed words and not actual talking. I applaud anyone, especially a woman, who tries to do thier own work on thier car. After being here a while ya somewhat get to know peoples personality. If some members here tell the newbies to "search" it's just that almost every question has been talked about in the past, sometimes 100s of times, so by searching ya get the answers quicker. And sometimes a newbie starts a thread like "Help, urgent, emergency" and it turns out to be something like the dash lights aren't lit b/c the dimmer is turned down. That gets to be annoying.

When you bleed the coolant system through that 17mm bolt, ya need to loosen it just enough for the air bubbles to come out, don't take the bolt out all the way. You will spill some coolant as the air comes out. I usually jack the car up in the front just to get that bolt a little higher but ya don't really need to do that b/c that is the highest spot on the engine already. Good luck and I hope ya get it figured out.