Cold Weather Woes

[Paul Sherman]

Hi:

I bought a '93 LS400 this October and like the car quite a bit,

however winter is pointing out two quirks I'd like to resolve:

1. Door locks and latching - As it hits sub-20 deg, the lock is

sluggish. once I get the driver door open, it doesn't relatch very well.

The first time, I held it closed and hit the lock, which worked.

This morning, it latched, but now it won't open, the lock is stuck

closed. I had to crawl out the passenger side. And now the

passenger door won't latch, plus I still can't release the driver's side

lock. I squirted lube in the lock last night, but not sure what else to do.

Can I access the latches without dissembling the door?

2. The heater - works great, as long as the engine is running over

over 1700 RPM. below that, the heater blows out cold air. No

problem on the highway, but waiting at the intersection gets chilly,

and stop and go driving is no fun. Is this normal or is there something

I can fix?

Any help on either front is greatily appreciated.

[Lexusfreak]

Hi:

I bought a '93 LS400 this October and like the car quite a bit,

however winter is pointing out two quirks I'd like to resolve:

1.  Door locks and latching - As it hits sub-20 deg, the lock is

sluggish.  once I get the driver door open, it doesn't relatch very well.

The first time, I held it closed and hit the lock, which worked.

This morning, it latched, but now it won't open, the lock is stuck

closed.  I had to crawl out the passenger side.  And now the

passenger door won't latch, plus I still can't release the driver's side

lock.  I squirted lube in the lock last night, but not sure what else to do.

Can I access the latches without dissembling the door?

2.  The heater - works great, as long as the engine is running over

over 1700 RPM.  below that, the heater blows out cold air.  No

problem on the highway, but waiting at the intersection gets chilly,

and stop and go driving is no fun.  Is this normal or is there something

I can fix?

Any help on either front is greatily appreciated.

←

- For the doors, I would suggest to use a high quality lube & makes sure ALL hinges, strikers & latches are well oiled (after applying the lube, open & close all doors several times so it works into the metal). Get some 'lock de-icer' & spray that into both front door locks on the outside of the car.

- As for the heater, it could be a number of possibilities:

- How old is your thermostat? It might need replacing &/or possibly a complete engine coolant flush (use the correct engine coolant that your manual suggests & mix with distilled water, usually a 50% - 50% is good practice). These are the smallest & least expensive items to check first.

After having these items done & your still having trouble, it could be your heater core, rad, rad hoses, water pump or something more complicated. Eliminate the small things first & go from there......keep us posted & good luck! B)

[90LS400Lexus]

I agree with Lexusfreak. Your heating system woe sounds like a faulty thermostat.

[Paul Sherman]

Thanks for the hints

I had de-iced the locks previously, so they're ok,

but the lock mechanism in the door seemed to be

the issue this time. Hope I can do this without removing the

panels - My '40 chev street rod is torn down in the garage,

so I'd have to try it outside - not fun in 20 deg weather

at my age,

The water pump has about 5K miles on it, changed just

before I got the car. How big a deal is it to change the

thermostat in the Lexus? (I often work on my own

vehicles, so learning curve shouldn't be too bad - heck

I've already done the dash light capacitor replacement

in this car.)

[Lexusfreak]

Thanks for the hints

I had de-iced the locks previously, so they're ok,

but  the lock mechanism in the door seemed to be

the issue this time.  Hope I can do this without removing the

panels - My '40 chev street rod is torn down in the garage,

so I'd have to try it outside - not fun in 20 deg weather

at my age,

The water pump has about 5K miles on it, changed just

before I got the car.  How big a deal is it to change the

thermostat in the Lexus?  (I often work on my own

vehicles, so learning curve shouldn't be too bad - heck

I've already done the dash light capacitor replacement

in this car.)

←

Try & 'saturate' the lock mechanism with a top quality lube including all hinges & see if it improves.

The Thermostat is very inexpensive & it's a 'plug & play' type of install, very simple......has to be done when the engine is cold. You mention the water pump was replaced recently.......did they do a complete cooling system flush at the same time? very important. B)

[VMF]

termostat has nothing to do with this, its either the tem sensor inside the cabin or the software problems.

when temperature is set to hot does it still blows cold air?

if it does does it blow cold air only from the dash openenings or from the openings around your feet as well?

[Lexusfreak]

termostat has nothing to do with this, its either the tem sensor inside the cabin or the software problems.

when temperature is set to hot does it still blows cold air?

if it does does it blow cold air only from the dash openenings or from the openings around your feet as well?

←

It could still be the thermostat that is stuck VMF......that why I suggested it as one possibility due to the year of the car & it being a simple repair & inexpensive replacement........the thermostat shoud also be replaced anyways as regular maintenance ever 5 - 7 years. Let's put it this way.......it won't hurt anything if it is replaced for about $10 - 15+. B)

[Lexus_Luxembourg]

I'd also bet on a faulty thermostat. Toyota seems to have used a special type that "opens" when it quits. Most thermostats simply stop working in the "closed" position, bringing massive overheating.

My idea is that the owner affirms the car heats fine when driving on highways but gets cold when stopped. This can not be explained by a software issue.

I'd also buy the genuine part from Toyota. Heck, I prefer a cold engine to an overheated.

For the locks: It does not help if you lubricate them now if ice has formed inside. Deicer won't help in all cases too. If the weather is as cold there as I believe they will not melt. So back to the old method: Put an electric heater inside and let it run for an hour. Take care where the heated air is blown. After an hour all ice inside the doors should have disappeared. NOW use lots of lubrificants on them. Also apply to all visible parts of the lock mechanism. If you are lucky this will do it.

Alain

[VMF]

what termostat does is switching contours for the coolant, when engine is cold coolant cycles just on the short countour and when engine is warmed up it switches to the regular contour, if it would be stuck in cold position the engine would overhear while if it would be stuck in the warm position engine would take much more time to warm up. Thermostat does not infuence temperature inside the cabin in any way. you prolly thinkgin about the heater core not the thermostat.

i mean how much colder engine should get during the stops so you would acutally feel it? you would see that drop on the temp gauge then. i had the same problem in my car

when during stops the openings on the dash would blow only cold air and the ones on the bottom still would blow hot air, the first thing to trouble shoot is the temp sensor inside the cabin, just put the temp to max hot and check if the problem would persist, if it will then check if cold air comes out from all the opening and not just the front one on the dash. openings next to ur feet are of a particular importance, compare the temp by hand with the dash openings. let me know o the results.

[Paul Sherman]

Hi all:

1. I think the locks are resolved, we'll see come the next rain followed

by freezing temps...

2. Heater - I've been doing the diagnostic homework some of you have suggested. Here's what I've found.

The heater works great at all RPMs while the car is warming up.

When it exhibits the symptoms, the car is fully warmed up and

blows cold air after about 30 seconds below about 1700 RPM.

a. Setting to "max heat" makes no difference.

b. The air is the same temp from all outlets.

c. The engine temp is stable in the middle of the gauge.

Questions -

On my other vehicles, thermostat failure shows up pretty

readily on the temp gauges, is that not the case here? Don't mind

changing it, just not fond of parts-swapping as trouble shooting.

The car seems to warm up normally (~10 mins) - what's normal?

I saw in another posting that there's a valve controlling water flow

into the heater core. Is that so and if true, would iit be worth a

check?

[Lexus_Luxembourg]

Hi all:

1.  I think the locks are resolved, we'll see come the next rain followed

by freezing temps...

2.  Heater - I've been doing the diagnostic homework some of you have suggested.  Here's what I've found.

The heater works great at all RPMs while the car is warming up.

When it exhibits the symptoms, the car is fully warmed up and

blows cold air after about 30 seconds below about 1700 RPM.

a.  Setting to "max heat" makes no difference.

b.  The air is the same temp from all outlets.

c.  The engine temp is stable in the middle of the gauge.

Questions -

On my other vehicles, thermostat failure shows up pretty

readily on the temp gauges, is that not the case here?  Don't mind

changing it, just not fond of parts-swapping as trouble shooting.

The car seems to warm up normally (~10 mins) - what's normal?

I saw in another posting that there's a valve controlling water flow

into the heater core.  Is that so and if true, would iit be worth a

check?

←

I agree with VMF that in this case it's probably not the thermostat. If your temp gauge shows normal temperature, about a hair over the second mark, the engine temp is right. If the thermostat would be blocked in the open position it would take way longer to heat up at all. But, at the attention of VMF, there ARE indeed cars that get cold when the engine runs. I own 3 different Land Rovers, all direct injection diesels. In a traffic jam their engines get too cold for the heater to defrost the windows. And there's no cooling fan running. I don't know if the LS400 engine is similar "overcooled" but I don't think so.

Back to your problem. VFM is right and it might well be a faulty sensor or the electric motor that governs water flow to the heater core. If it were my car I'd manually open the valve and save the problem for spring time. Not an ideal solution, I agree. But at least you will stay warm.

Alain

[VBdenny]

I can't speak for the 400 but I know most cars have a vacuum or electric cutoff to stop the flow of heated water to the heater core. This is activated when you turn on the AC sothe heat doesn't mix with the cold air (in summer). I had a Buick that it went bad in the winter in Syracuse and eventually I had NO heat. Just something else to check