I had a problem with my heating in the cold Canadian winters and just had the dealer fix it. It seems that if your anti-freeze is to thick (pure) it won't flow properly to the core. Drained and replaced with deluted mixture. Along with a vapour lock being fix I now have lots of heat.

 

So you had 100% antifreeze in your car!?:eek: How long was the coolant in your car that way?

Glad you have heat again my friend...

 

What is a vapor lock, and where is it? Did you change the antifreeze yourself? always use 50/50 and remember to use distilled water.

 

is basically a gas bubble that has formed somewhere in a line carrying liquid, it doesn't easily move, flow, around a restriction or bend in the line and thus acts as a blockage restricting the amount of liquid that can pass. The smaller the line and/or the thicker the liquid the more prone you will be to this happening.

I suspect a vapor lock had more to do with the lack of heat than the predominance of anti-freeze.

 

Lets see if you guys can help me with the other problem I have - it's posted in engine/transmission forum. Thanks.... O2

 

Thanks for the informative posts. I'm having the same problem in my 92 SC400 as well- no heat, unless I gun the engine hard- then there is a wave of heat that may or may not last.

So that sure seems like a Vapor Lock issue. Question is, what do I do about it? My beloved (now stolen) 1972 BMW 3.0CS had a bleeding valve right at the top front of the engine, but I don't know if the 92 SC400 has one.

Anyone have any ideas on what to do about a Vapor Lock?
=============================================
02-04-02 UPDATE TO THIS POST: Problem solved - low coolant level caused the vapor lock. See below for everyone's helpful suggestions and my admission that I am an idiot for not checking coolant lever sooner.

 

That was a wonderful automobile, I restored a 1974 Bavaria (rip). Vapor lock and overheat was definatly and issue with her, as was balancing the dual carbs!

 

Perry:

I had a car that did the same thing about putting out lots of heat as long as you had the throttle open. It was a bad vacuum controlled valve that let hot water into the heater core. Do you get heat if the engine is not running?

Wiley

 

Well, to try that test you suggested, I drove home and pulled into my driveway, turned off the engine, then turned on the ignition (but not start the car), and turned the heater to "HOT", and to answer your question, no, the heater fan did not blow any hot air.

But I am not certain what that proved- with the engine off, the water pump is stopped, so no water, hot or not, circulates anyways. That would be quite a trick to get heat with the engine off, no matter how healthy the cooling and heating system is.

 

Try this. I posted this question on the UK Lexus site and got an answer that I tried - it didn't work but it might for you. Go to this web site under forum, electrical. Look for the heading "Canadian needs advise" there is a picture posted able jumping some vacuum connections on the heater actuater.

www.jkwebdesign.co.uk/lexusclub

Good Luck

 

Perry:

It was a long shot, but my theory was that if low vacuum caused the heater valve to open, it would be open when the engine was off. However, you're correct in saying that without the water pump circulating coolant, there's no heat going to the heater core.

Wiley

 

Thanks to Wiley and BriMcc for their posts. You're right, Wiley- it may indeed be a vacuum problem. And I registered with the UK Soarer site BriMcc mentioned and found quite a bit of interesting reading. I'll take a close look under my hood this weekend and let you know what I find.

And thanks for the thoughts, Camshaft, but all the controls and readouts inside the car appear to be fine, so I think the signals to open up the heater valves is getting there, but some circulation/vapor lock/heater valve problem is preventing hot water from going through the heater core.

If it IS "Vapor Lock", as has been suggested, does anyone know what, if anything, I could do to eliminate it?

Just my luck- Los Angeles is experiencing its coldest weather in many years. Admittedly, I should not be complaining, since most parts of the country wouldn't mind lows in the 40s and highs in the 60's in winter, but it still is cold enough for me to miss my beloved heater!

 

Try 20 below, a foot of snow, freezing rain and traction control that's not working. It's winter in Ontario.

 

I found that if you drive the car for about 2 minutes, turning the **** to HOT, and turning it off and then to auto, it will come on. You know it is on when you see a bar or two. That is the way that I have gotten it to turn on recently. Maybe a short in the temperature control?

 

Well, it all makes sense now. I've had this car for 5 years, and I don't recall ever having to add coolant, so I never did. Every time I checked the coolant level, it was the same, so I guess I stopped checking it a year or so ago.

I don't know what caused me to check it this past weekend, but I did and sure enough, there was no coolant in the overflow tank!
So I added a quart or so to bring it up to the proper level and problem solved- I now have heat!

So I guess it was a vapor lock problem- but one easily solved!
I'm guessing that once the coolant level get low, the air pocket that forms is at the highest part of the system, which is the mixing valve at the top center of the firewall.

It's a good thing to know that once the coolant level starts slipping, the car still runs at the proper temperature but the heater won't work.

Thanks for everyone's suggestions and I promise to check the basics from now on before panicking!