No Heat In The Interior

[jbrubaker]

Well, hoping this is as simple as it seems, but juswanted a couple of opinions, if I could get them.

Wife was driving the car last friday, overheated. She pulled it over, I went to pick it up, refilled the engine block, found the culprit to be a defective radiator cap. Replaced it, level in reservior is perfect, temperature gauge styed right in the middle.

Drove the car about another 100 miles, and the temperature gauge went from the middle of the range to laying on the bottom of the range, and the car quit blowing heat.

I suspect a thermostat that is stuck wide open (affected by the engine overheating), or perhaps the previous owner removed the thermostat all together. Not sure which, and not completely convinced that this is the issue.

I know, an engine running very cool, that is great, but here in PA where winter has set back in it would be great to have heat back in the cab.

BTW, water level is still pefect in the block and in the overflow reservior.

Any thoughts, and where is the thermostat located?

[amf1932]

There is the possibilty that air pockets are trapped in the cooling system. Try setting your heat control up to the highest heat and run the car for awhile.

Even if the previous owner took out the thermostat, or it's stuck in an open position the temperature gauge should move slightly. Besides, it's important that the thermostat is functioning normally for the engine to run properly over long periods of time. If the first suggestion doesn't help, I would replace the thermostat.

[jbrubaker]

Alan,

I have done that in a sense going down the road on a trip for about 100 miles. (left the heat on, not high, but set at 80 degrees). I wold assume that it would have the same afest a what you described o do, but will check tomorrow AM o be sure that the engineblock is full

I read in one of the threads that Toyota thermostats wer made to failin th open position. Can anyone confirm this?

Also, where is the thermotat locaed? In the housing under the filler neck?

[SKperformance]

Air pockets usually create hot spots not cool ones as it cause lower internal pressures. So i wouldn;t think it would be air.

Does the engine feel hot ?

Do the rad pipes feel hot as in can you touch them after running the car for an hour or are they warm enough to handle holding them. Is the climate control in auto or are you manually selecting fan speed and temp?

Is the fan on the rad spinning at full speed?

If the car is running and the heat quits but the engine is still hot it is either the rad fan is stuck on or the control valve on the firewall has closed keeping the hot coolant from going into the evap core to be blown by the fan to heat the interior.

I doubt it is the valve as the temp needle dropped as well. So it might be the thermostat. How long does it take to heat up from a cold start?

[jbrubaker]

My experience with air pockets has been intermittent heat in the cab.

I will check the 'warmth of the hoses and the engine tomorrow am, as well as the water level.

I had thought about the heater valve, based on some similar experience with my Mercedes, but had ruled it out when the temperature gauge registerd lowe than normal.

Where is the thermostat located?

I will check the rad fan as well, but do not think tht is he issue. I have not driven the car, just my wife, but will post what I find tomorrow.

Thanks again.

[jbrubaker]

Top radiator hose is warm to touch, but not too hot.

Rad fan does not run continually.

It took about 3 tablespoons of water until it was running out the neck of the filler cap.

In my estimation, No air pockets.

Going to change the thermostat today.

Is the thermostat on the top of the engine under the filler cap?

[amf1932]

The thermostat is not located under the filler cap! Drain the coolant. There is a water inlet pipe & O-Ring connecting to the water pump that has to be removed first, along with the electrical connectors. You then remove the thermostat housing and remove the thermostat. Put in the new thermostat and reverse this procedure.

Personally, I would bring the car to a knowledgeable mechanic or radiator company to do this job, unless you are mechanically inclined. ;)

[jbrubaker]

Thanks, Alan. I think i can handle it, just wanting to know what kind of time to alot.

I used to rebuild engines (mainly fords), and have done quite a few engine and tranny swaps, including Mercedes in the luxury car.

Appreciate your help with where to look. Jus not quite as familiar with the imports.

While I am at it, draining the coolant, any reason why I should choose to change from the green coolant to the orange?

[amf1932]

My '94 ES came from the factory with the red coolant, so I would advise changing back to what Lexus originally used. If you do, make sure to flush out all the green stuff, as best as possible. I think that after you change the thermostat all your troubles will be gone.....hopefully. ;)

[jbrubaker]

I do, too. Will let you know tomorrow...

[SKperformance]

It is funny most people who have cooling issues either have a 92-93 es 300 with an iron block that has problems. Or they have the wrong kind of coolant..Get a prestone flush kit.It comes with a pipe t to hook up a garden hose and it will flush all the old coolant out of there.

[Latoilette]

my last car had a iron block. the car had cooling problems during summer and long idle.

[jbrubaker]

So I surrendered. After remoing the timing belt cover, I did notice that the water pump was new. Timing belt looked good, but maybe not new.

Couldn't figure what else i had to remove to get to the thermostat. So I put it all back together.

Will get it to my mechanic first of the week...

[amf1932]

Sorry to hear that you couldn't find where the thermostat was located, but you were looking in the wrong place. The timing belt cover doesn't have to be removed to do this job. In any case, I called up my Lexus dealer and found out that they get about $150 to do this job. I then called a local mechanic and he said about $90. Parts included, plus the cost of the anti-freeze. This will give you some idea as what you can expect to pay for this job. Good Luck. ;)

[jbrubaker]

Where am I to look, then? I saw where the filler neck came off. I already have the thermostat, obviously.

One thing I did learn, though...

Not so much to take the timing belt off and change it, and did find out that the water pump is fairly new (judging from the brightness of the aluminum of it and the dirt on the rest of the componenets.)

So can anyone give me a step by step?

[amf1932]

The filler neck is on the top part of the radiator. You should be looking at the lower inlet of the radiator and follow the water inlet pipe to the thermostat housing. As the top Lexus mechanic told me, "It's no big deal" ;)

[jbrubaker]

My filler neck is actually on the front of the engine, but I will follow the bottom rad hose from the radiator.

According to the manual I have, the temperature sensor is on the front of the thermostat housing, but is does not say where that housing is...

Will let you know.

[jbrubaker]

Ok, so here is the fix.

First of all to refer back to what I read somewhere (I think in a different thread), I want to confirm that the thermostat does fail in the open position. Made with three little 'ears' that lock it open when it gets hot. Sorry to say that the replacements are not made that same way. Just a standard thermostat.

Thermostat housing is located off bottom rad hose. Bunch of stuff to remove and reinstall, but even with the guesswork, took about 1 hour.

Thanks Alan, SKperformance, and everyone else, for the input. Momma is warm again so we will all be happy!

[amf1932]

Good for you. I'm happy to hear that you were successful!! :D