No Heat - blows cold

#1 03-28-2003, 09:00 AM

I have been driving my (newly purchased) 95 LSi the past week or so. It drives and runs pretty decent.

The only thing is there is no heat.

It justblows ice cold air all the time.

The previous owner had taken it to the dealer. They replaced the thermostat. Still no heat. Then they said "To further diagnose we need to take apart the engine, it could be the head gasket". The previous owner declined.

I have put over 100 miles on the car and the engine seems fine. No white smoke, oil is not contaminated and the engine sounds/feels smooth.

Both hoses going into the heater core are warm. So does this mean the heater core is good? My mechanic suggested I take the hoses off the heater core and flush it out with a garden hose, to make sure it isn't blocked.

He also suggested I swap out the climate control switches (on dash) with my other SVX to see if that is the problem. Could this possible be it?

The temp guage reads about 10 to 15% higher than my other SVX, which runs at horizontal for normal operating temp.

Should I do the things mentioned above? Any other suggestions/feedback would be very appreciated.

Thanks,
Tapper

svx_commuter · #2 03-28-2003, 10:18 AM

Now that thst youknow your heater core is connected I will suggest two things to look at: 1. The air duct door (or damper door) is stuck or broken in the cold air position. But I do not not how to check this or if it's accessable. 2. The heater core is plugged up. But this is not likely since both hoses feel hot to the touch. But the hoses could be hot if the flow is real low thru the core. Does the air get warm when the fan is operated on low say for 10 minutes? Do the heater core hoses stay hot when the fan is operated on high for say 10 minutes?

kuoh · #3 03-28-2003, 10:58 AM

That does seem to point to some kind of problem in the cooling system. If the engine is up to normal temperature, then the hoses going to the heater core should be hot, not just warm. Has the waterpump been checked out? Also, check the coolant level in the radiator, not just the reservoir.

KuoH

Quote:

Originally posted by TapperManor
The temp guage reads about 10 to 15% higher than my other SVX, which runs at horizontal for normal operating temp.

#4 04-21-2003, 07:07 PM

I finally got to work on this problem. I flushed out the heater core and it seems OK. Both hoses on each side get very hot. But the air is still ice cold.

A friend suggested checking the fan that would force air through the heater core. What does that look like? Is it under the dash behind the glove box?

I still haven't swapped the heater control panel out yet. I don't think that is it. Is this part prone to failing? (the circular switch with the temp setting)

Thanks for any and all replies

Tapper

huck369 · #5 04-21-2003, 07:30 PM

Quote:

Originally posted by svx_commuter
Now that thst youknow your heater core is connected I will suggest two things to look at: 1. The air duct door (or damper door) is stuck or broken in the cold air position. But I do not not how to check this or if it's accessable. 2. The heater core is plugged up. But this is not likely since both hoses feel hot to the touch. But the hoses could be hot if the flow is real low thru the core. Does the air get warm when the fan is operated on low say for 10 minutes? Do the heater core hoses stay hot when the fan is operated on high for say 10 minutes?

I'm with SVX_commuter,
I think it's the flap in the heater box, it's probably stuck.
I'm working on my door locks tomorrow evening, and I'll look, to see where you'd need to look, to move the rod.
Will try to post tomorrow night, on my findings.

Ron Mummert · #6 04-21-2003, 07:36 PM

Nonetheless, why would Tapper's temp gauge read higher than "normal"?

Ron (curious).

huck369 · #7 04-21-2003, 07:48 PM

Ron,
Different cars run different temps, could be a differance in the gauges, could be a different temp termostat, slightly blocked rad. ect. ect.

The fact that BOTH hoses are getting hot means water IS flowing throught the heater core, so it almost HAS to be inside the car, and the only thing that I can think of is the flop door that flips between the AC box, and the Heat Box.

The bright side.....warmer weather is coming

Ron Mummert · #8 04-21-2003, 08:04 PM

I'm wondering that if the flip-flap door done flopped, then where does the heat go? Could this be creating the warmer than normal indicated temps? (I say normal is needle floating on the waves, summer & winter). As is often stated, if a car loses coolent & begins to run hot, cut the A/C & run the heater to help dissipate the heat.
Same principle?

Ron (still curious).

#9 04-21-2003, 08:21 PM

Thanks for the input. I will look for the flapper box.

gotta run ..the wife just got home

huck369 · #10 04-22-2003, 05:18 AM

Quote:

Originally posted by Ron Mummert
I'm wondering that if the flip-flap door done flopped, then where does the heat go? Could this be creating the warmer than normal indicated temps? (I say normal is needle floating on the waves, summer & winter). As is often stated, if a car loses coolent & begins to run hot, cut the A/C & run the heater to help dissipate the heat.
Same principle?

Ron (still curious).

Hey Ron,
When the flop door is set to allow cold air in, no air flows across the heater core, so it doesn't help to cool the motor, but if it's cool enough to run the heat, the motor shouldn't need help staying cool.

The blower fan pull air from the outside, then the flop door diverts it to either the AC Box or the heater Box, so only one will get any air flow at a time (granted it can also mix the two to get the desired temp but I’m assuming it’s one way or the other)

Unless the gage runs drastically higher than the other car, I’d say it’s just the difference in the 2 cars, they will vary a little car to car.

Anyway, I’ll try to look at mine tonight when I get home.

svxistentialist · #11 04-22-2003, 06:37 PM

Do the diagnostic.

Drive the car a bit, to heat up the water. Switch off. Turn on the ignition while holding the on/off switch of the heater, and the auto switch on. This causes it to check everything. It will run a sequence, checking all servos. If the exterior flap is stuck, it will show a code.

Joe

#12 05-20-2003, 06:15 PM

I did the diagnostic above. I got a code number of 13 on the temp display.
Does anyone know what this means?????

Strangly enough, the heat seams to be working now. Could the diagnostic test also reset something?????

Tapper

OHHhhh, also I repaired a leaking radiator hose clamp.

Earthworm · #13 05-22-2003, 07:11 PM

Code 13, as I recall, is normal if you are not running the diag in direct sunlight.

svx_commuter · #14 05-22-2003, 07:16 PM

NO WAY

The climate control can be self checked.

That's great.

#15 05-23-2003, 07:15 AM

I wanted to post this info, for everyones benefit. I had sent a PM last night to "svxistentialist" and this was his reply. (thanks joe)

I will post a follow up to this post after I perform the tasks below.

Tapper

Quote:

Tapper,

This is possibly good news. #13 refers to the sunload sensor. It is a small black sensor on your dash, high up, possibly 1" in size. What it can mean is this sensor is broken or shorted. What it most likely means is you ran the test at night time, or in your garage, without shining a 100w bulb on this sensor. If you redo the test in
bright sunshine, and no code 13 shows, then your electrical doors etc are OK.

It think it is possible the diagnostic routine caused a sticking valve to move, and give you heat. You would have to ask yourself why it was stuck if so. Is it gunged up inside [check the condition of your coolant] or is the
valve swivel rusted (could you have a leaky valve)?

Chance doing the diagnostic a few times, it may free up the water valve. Check it out under a 100w bulb
shining on the sunload sensor at night, just for interest, to see if the code goes away. You may well have freed it up permanently, hope you have.
Joe