m8554

I have a 95 LS400. The heater works fine until you come to a stop. Then the heater blows cold air. The temp gauge runs normal and I checked the coolant level. As soon as you accelerate, the heat then works fine. Anyone else with this problem? Any input would be appreciated. Thanks.

Shaffer

This is ironic. Just last night, my aunt phoned me and told me that her 2001 Nissan Altima SE with 28K miles did not have any heat while she was stopped, but as soon as she would accelerate it would warm up instantly, just as you described. I asked my dad for her and he said he thought it may be low coolant, but I am assuming that her car is less than two years old, that it would not be low on coolant. She said that she would just get her husband to take it to the Nissan dealer and let them check it, since it is still under full warranty. The car needs other work, so I guess they will take it down this week. I will let you know what they tell her, because it is obviously the same problem year car has.

Whats even more ironic- my 1998 Ford Taurus (with 245K) also does the exact same thing, so
I am anxious to hear the problem myself, as I want to get the Taurus in good working order before I sell it.

Shaffer

To update- my uncle added coolant to the overflow and now the heat works perfectly, even at a stop. What I find odd however, is why a 2001 model car, with 29K miles would be low on coolant? I told my aunt that I would still tell the dealer and have it checked.

Good luck with your heating problems.

m8554

I followed the fill instructions on the coolant overflow tank for refilling. This was to fill to neck and run car until at operating temp, then with heater control on HOT run at 2500 rpm for five minutes and top off to top of filler neck. I did this and had to add about 12 ounces of coolant, but the problem still exists.

Dlewbell

Has anyone found a definite answer to this problem yet? I have a '95 SC400, and it just recently started having the same problem. It also started idling higher with the heater/AC running than it did in the past.

cmotomn

I just had the EXACT same problem with my 95 LS400 a few weeks ago. Bad news was the water pump was leaking and had to be replaced ($800 @ the Dealer). Fortunately, that fixed the problem!

Shaffer

On my aunts car- it worked again when coolant was added. My 98 Taurus still does this, but I have had it with that car and rarely drive it. I think I may have it sold. I checked the coolant and it was fine. Perhaps something in the heater system is the problem.

Typically- low coolant or a bad thermostat will cause no heat @ idle.

Dlewbell

That fixed it. Thanks. I would've never thought to check the engine coolant levels. I guess the cold weather is what's kept me from running hot all this time.

Lexozz

You can't be serious! You probably are one of those people who takes their car to the dealer to get air put in your tires with a $50 labor charge and a smile.

Shaffer

Huh? I do not know what you mean. The car I was referring to was my aunts car. I said that I told her to have the dealer to check it before I thought about telling her to check the coolant level. At any rate- if a car is under FULL warranty- why not take it to the dealer to see why the level is low?

Lexozz

Let me elaborate! You are supposed to change you coolant every season. The coolant level will eventually get low because it does run through a 1000 degree engine, even hotter in the mid summer with the a/c on. When the engine gets extremely hot it builds up steam especially if mixed with water that forces anti-freeze out of the over flow tank. This will definitely cause low coolant level. If you don't change the coolant it will get discolored and over heat the engine and blow your head gasket.

Sure if the car is under full warranty, of course take it to the dealer!

Shaffer

I agree. It is under warranty- which is why I told her that.

About the coolant- I never knew it was supposed to be changed every season. Does this only apply to Lexus? I have had MANY different cars over the years and never changed the coolant and they always stayed full, nor have I ever heard of anyone else doing this.

I know that GM put a 5-year coolant in their late 1990s cars. I guess they still have it. My mothers 1997 Oldsmobile has a sticker on the radiator cap that states that the coolant is maintainence free for 5 years, or 120K miles. I know that I have put over 20K on my 92 Buick and I have had it for 2 years and I have never changed the coolant on it and it still looks perfect and has never dropped below the line on the overflow tank and the radiator is always filled to the top when I check it and it has been like that for 2 years. It always operates at normal operating temperature and the coolant always shows a good freeze protection reading.

I am glad now that I know that the Lexus coolant should be changed yearly. I will have to look at my owners manual to see what mileage interval they recommend as well.

spxChrome

To late now I guess, but you should have got the timing belt changed at the same time? Just posting this in case somebody runs into the same situation.

abaisley

Bump... if there's a more recent version of this thread, my apologizes - I searched and found this one.

First of all, 93 LS400, 155,000 miles

I started having this problem half way through this winter (just my luck!). No heat at idle, but works okay when on the highway. It doesn't work as well as it used to, but it's okay on the highway. On NYC streets in never gets warm in the stop and go traffic. It just blows cold.

I read this thread and checked my coolant today which was barely low, I topped it off and it made no difference. The water pump was replaced less than a year ago, so I doubt that's the problem.

Any other ideas?

Thanks for any help,

Andrew

Lexusfreak

When was the last time you changed your engine coolant (and what type of coolant was used)? Any other parts replaced such as the water pump, thermostat etc?