No Air From Heater

[nwotank]

My ac seems to work, although I can't really tell any difference between normal and max, it never really gets very cold but does get colder than outside temp, i tried the heater recently and even though i hear the blower there's no air that comes through the vents. Any ideas on what the issue could be?

Here's a video of my compressor stopping and starting:
View My Video (http://tinypic.com/r/2dso31i/5)

[DMC5180]

Most likely your Mode switch needs to be rebuilt. The electrical side works but the Vacuum part does not. After you shut the engine off are able to here the vacuum doors operate if switching positions or do you hear abnormal hissing?

[Rich]

Let's be clear on the problem description before any mechanical work.

You are reporting 2 problems - confirm these or correct these restatements:

1. A/C works and you ARE getting air thru the dash and door vents in A/C Norm and A/C Max. The A/C vent temp from those vents isn't very far below ambient.
2. With Heater on "No air thru the vents" refers to exactly which vents? In the Heater position you say get no air thru "the vents". You do not say whether you get any air flow from the footwell.

Problem 1 could be caused by low refrigerant charge due to leakage. Depending on when the last top-up of refrigerant was this could be "normal" or not.

Problem 2 is not a problem. In the Heat position the upper (center console) vents do not blow. In that mode most of the airflow is to the footwell vents. Some air also goes to the door and defrost vents.

The cycling frequency of your compressor at idle is consistent with low refrig. charge, too.

[DMC5180]

Let's be clear on the problem description before any mechanical work.

You are reporting 2 problems - confirm these or correct these restatements:

1. A/C works and you ARE getting air thru the dash and door vents in A/C Norm and A/C Max. The A/C vent temp from those vents isn't very far below ambient.
2. With Heater on "No air thru the vents" refers to exactly which vents? In the Heater position you say get no air thru "the vents". You do not say whether you get any air flow from the footwell.

Problem 1 could be caused by low refrigerant charge due to leakage. Depending on when the last top-up of refrigerant was this could be "normal" or not.

Problem 2 is not a problem. In the Heat position the upper (center console) vents do not blow. In that mode most of the airflow is to the footwell vents. Some air also goes to the door and defrost vents.

The cycling frequency of your compressor at idle is consistent with low refrig. charge, too.

Good points for clarification. Also, Clutch cycling frequency is also dependent on OAT. If he's looking for heat it's probably an indication the OAT is in the 40's. I would expect to see idle cycling like that with low ambient temps. Unfortunately his left column info lacks a location to know if he lives someplace warm or cold.

[nwotank]

Let's be clear on the problem description before any mechanical work.

You are reporting 2 problems - confirm these or correct these restatements:

1. A/C works and you ARE getting air thru the dash and door vents in A/C Norm and A/C Max. The A/C vent temp from those vents isn't very far below ambient.
2. With Heater on "No air thru the vents" refers to exactly which vents? In the Heater position you say get no air thru "the vents". You do not say whether you get any air flow from the footwell.

Problem 1 could be caused by low refrigerant charge due to leakage. Depending on when the last top-up of refrigerant was this could be "normal" or not.

Problem 2 is not a problem. In the Heat position the upper (center console) vents do not blow. In that mode most of the airflow is to the footwell vents. Some air also goes to the door and defrost vents.

The cycling frequency of your compressor at idle is consistent with low refrig. charge, too.


1. Yes, ac works and I do get air through the dash and vents in normal and max. However, between these two settings I really can't tell much of a difference. When its set to max it does hiss on and off. I had the refrigerant topped off a couple of months ago. I was told it was low when I took it in. I take my car to a mechanic who is not too familiar with Deloreans, but he suggested replacing an expansion valve and a dryer. In the summer it can stay above 100 for days so having cold ac is pretty important. I expected a small car like this would be pretty easy to cool down.

2. I meant the center console vents, I do notice there is air from the footwell but I was expecting air to continue to flow from the center vents also. But thank you for clearing that up. I live in Texas so it doesn't get cold too often here.

[nwotank]

Good points for clarification. Also, Clutch cycling frequency is also dependent on OAT. If he's looking for heat it's probably an indication the OAT is in the 40's. I would expect to see idle cycling like that with low ambient temps. Unfortunately his left column info lacks a location to know if he lives someplace warm or cold.

It was about 65 out when I took the video, San Antonio TX, but to clarify I had the setting to Normal AC when I took the video, not to heat.

[DMC5180]

Was the temp knob on full heat? A/C Norm will allow hot and cold blending.

Delorean A/C does not use an Expansion valve. It's a fixed orifice tube system.

[nwotank]

Was the temp knob on full heat? A/C Norm will allow hot and cold blending.

Delorean A/C does not use an Expansion valve. It's a fixed orifice tube system.

No actually it was on full Cool, the knob won't actually move to the heat side, it will click on full Cool and move a little back but not much.

[Rich]

OK, thanks for answering on the vents and the control settings.

So now you have:
1. An A/C system that blows "kind of cool" but not "cold".
2. A temperature control knob that is stuck in full cold position and no urgency to remedy it because the Texas climate isn't too harsh.
3. Blend doors and mode switch seem to be OK since the air flows are coming out in the right places at each mode.

Suggesting you put a set of A/C gauges on your system or get it to a shop with gauges and see what's going on with #1. Having topped it up recently you'll want to be sure it's still got an adequate charge. If so then the problem's elsewhere, if not you have a refrigerant significant leak to look after.

Don't expect a big vent temperature difference between Max A/C and Norm A/C when it's 65F outside. The difference between those modes is where most of the inlet air is taken from, either the cowl inlet (outside air, Norm) or the cabin (inside air, Max). When the cowl inlet temp and the cabin temps are similar then you'll get similar A/C vent temps in both Max and Norm A/C. The "Max" setting on almost all car A/C systems is misleading, implying that the compressor is delivering more cooling power somehow. Same cooling power, different air inlet path.

Not sure what you mean when you say something hisses on and off.

Let us know if you want any advice about the stuck temp. control knob.

[Ryan King]

I had a similar problem on my car...

Part #25, the arm that controls the center vent snapped off, which stopped air flow to the center vents. Take a flashlight and peer in through your vents to see if the door is closing and opening as its supposed to.

http://store.delorean.com/c-302-7-1-1-heater.aspx

-Ryan

[Patrick C]

I had a similar problem on my car...

Part #25, the arm that controls the center vent snapped off, which stopped air flow to the center vents. Take a flashlight and peer in through your vents to see if the door is closing and opening as its supposed to.

http://store.delorean.com/c-302-7-1-1-heater.aspx

-Ryan

Same problem here. Take out the glovebox for better access and you can superglue the plastic arm back together. Still holding strong for me 6 months later.

[Ryan King]

Same problem here. Take out the glovebox for better access and you can superglue the plastic arm back together. Still holding strong for me 6 months later.

I did the exact same thing!! Holding strong!

[DMC5180]

Same here.

[DMCMW Dave]

They don't just snap off. We usually find this problem shortly after someone has [a large electronics department store who shall remain nameless] install a stereo unit. They also seem to routinely mess up the vacuum hoses and/or other wiring back there.