why doesn't my front defroster work?

[50 Proof]

Does my A/C need to be charged in order for the front windshield defroster to work? I can have the defroster cranked up to the max, with the lever on cool or warm and it'll blow for 10 + minutes and still not do a **** thing. Does anyone have this problem? How can I fix this? I hate having to drive with my head sticking out the window.

[cjwanner2000]

do you mean nothing happens as in it doesn't blow hot air, or doesn't blow at all or what?

[MurPHy]

Sounds like a shot heater core. Do you smell antifreeze when it's running? I had the same problem awhile back.

[negusm]

Sounds like your heater core isn't getting hot. Is it blocked in the lines somewhere?

Do you feel air coming through the vents?

-Mike

[cjwanner2000]

oh yeah, which car? i see an 88 and an 86 in your sig. i know on my 79(w/ ac, not charged) i have a vaccum line coming out of the firewall that must be hooked up or i don't have any control over where it blows the air(floor vents or defrost).

[50 Proof]

it's for the 86. It blows air alright. It blows really well. It's just the air that blows out doesn't do jack to clear the window up. I don't understand it. After a loooong time finally the window starts to clear up around the general area where the air is blowing but the window never clears up all the way. The heater core is less then a year old.

[50 Proof]

Sounds like your heater core isn't getting hot. Is it blocked in the lines somewhere?

Do you feel air coming through the vents?

-Mike

The heater works great in the car, I don't think anything is blocking any lines, but then my car gets really hot when I sit in traffic and this is with a fluidyne radiator, new hoses, new heatercore, new thermostat, water pump is good. It's possible the coolant passages could be clogged maybe. I dunno. The heater does blow hot air though and I do feel air coming through the vents.

[Zap's 85 GT]

The vent system is primarily switched by vacuum. Maybe one of the lines has become disconnected or the defroster door/cylinder is stuck.

Does your car switch between FLOOR and VENT and MIX properly? If not maybe your primary vacuum line going to the HVAC control isnt hooked up. There should be a line for that in the engine compartment that goes from the main vacuum tree into the firewall.

[50 Proof]

Does your car switch between FLOOR and VENT and MIX properly?

I'll check in a little bit when I leave for work.

[50 Proof]

The vent system is primarily switched by vacuum. Maybe one of the lines has become disconnected or the defroster door/cylinder is stuck.

Does your car switch between FLOOR and VENT and MIX properly? If not maybe your primary vacuum line going to the HVAC control isnt hooked up. There should be a line for that in the engine compartment that goes from the main vacuum tree into the firewall.

This is what happens..
When Mix is on, only the defroster and floor vents have air coming out through them. The vents facing me are dead. When I put the hvac controls onto floor or defroster, air blows through just fine. When I put the controls on vent, things blow through just fine too. So I don't know. Air blows through the defroster vents but the window just doesn't defrost, very frustrating. Could this be a result of the A/C system needing to be recharged?

[negusm]

So you get a good SOLID stream of HOT air going past your windshield?

If so, then you have a MAGIC windshield! Call Ripley's!

What are the temperatures there? in so cal? It can take 10 minutes (under load) for a car to warm up and get the heater core hot enough to defrost the windshield....more time if you just let the car idle with no load.

Once the air coming out of the defroster is HOT, it should take 3-5 minutes to defrost the windshield.

Your AC system should have no effect on the heater. My AC was discharged for the longest time and the heater worked.


-Mike

[50 Proof]

yea i can feel a good stream of air going across the windshield. The defroster in my friends civic works off of the A/C and clears the whole windshield in probably not more then 30 seconds. Damn new cars.
After the engine has warmed up, the defroster will defrost but it just takes forever and a day to do it.
it just sucks though because in the morning I can't see jack out the front windshield. I can't sit there and wait for the defroster to clear the window, i'll be late to work if I do that. I can't drive the car to put load on the engine to get things heated up because I can't even see out of the windshield. oh well. Maybe I should just stop my complaining and deal with it :lol:

[roller4v]

The Defrost setting works in conjunction with the A/C compressor. The A/C system will dehumidify the air prior to send it thru the Heater core and up to the windsheild.

Your defroster would work better if your A/C was also working.

Steve

[Marz]

the previous owner of my 85 had the AC updated to the newer charge and damn.. all I can say is that windshield defrosts very quick compared to the other FOXes I've had. The other FOXes I've had... the AC either didn't work or KINDA worked. But even the ones that didn;t work the defroster still did it's job... alot slower though.

[50 Proof]

hmm, i guess I should get the A/C fixed then. Does anyone know whats involved with converting to the newer type of A/C and how much it costs? Maybe I should put up a new thread...

[GT350R]

The heater core is less then a year old.

Bad heater core.

Did you put a cheapy aftermarket one in?

Have you even touched those hoses since you put the heater core in? Are your motor mounts original?

Seems like even a slight breeze will crack a tube in one of those piece of crap aftermarket cores.

Get a Ford core. 45 bucks or so, but the tubes are braced. Also get new hoses and spray/soak the hoses in WD 45 before slipping them on.

[roller4v]

I can give you some advice on the a/c conversion. I've done two of them. One the expensive way and one the cheap way. But why don't you start a new thread and I'll post to it.

Steve

[50 Proof]

The heater core is less then a year old.

Bad heater core.

Did you put a cheapy aftermarket one in?

Have you even touched those hoses since you put the heater core in? Are your motor mounts original?

Seems like even a slight breeze will crack a tube in one of those piece of crap aftermarket cores.

Get a Ford core. 45 bucks or so, but the tubes are braced. Also get new hoses and spray/soak the hoses in WD 45 before slipping them on.

it's a ford heater core, the motor mounts are bad, they have 187k miles on them. I haven't touched those hoses or tubes since installing the heater core. I don't get that film on the window when a heater core is bad, and hot air blows great through the vents. Otherwise, how else can you tell that the heater core is bad?

[GT350R]

Is this in the comvertible?

If so, start looking for leaks. I have seen this on cars with trunk leaks or wet carpet.

[50 Proof]

it's in my 86 T-Tops, no leaks so far, carpet is dry.

[LTDScott]

The defroster relies on the A/C compressor to de-fog the windows. Apart from making the air cold, part of the A/C's job is to remove moisture from the air. So if you flip your controls to "Defrost," the air should come out of the dash vents and the A/C compressor should kick in.

So if your A/C isn't working, the moisture isn't being removed from the air and the regular "non-conditioned" air blowing on the windshield won't help much. Does your normal A/C work?

On my Mazda, I have to turn the A/C on manually (has a separate switch) even if the defroster is on. If I don't turn the A/C on, it'll take forever to clear the window. I don't think the heater core has anything to do with your problem, unless it's leaking and CAUSING the windows to fog up.

[FoxChassis]

Several times in this thread I've seen Corey say "defrost". So are we talking about "frost" on the windshield that's not clearing up or "fog" that's not clearing up?

[negusm]

Are we talking de-fog or de-frost?

More of a concern to me is the frost on the outside of the car...which won't be affected one bit by the moisture in the air coming out of the heater...

-Mike

[50 Proof]

Several times in this thread I've seen Corey say "defrost". So are we talking about "frost" on the windshield that's not clearing up or "fog" that's not clearing up?

sorry, i guess I mean defog. I can take my hand and wipe the inside of the window clear kind of(it gets fogged up again). The windows are not fogged up because of a bad heater core. Frost on the outside of the windows doesn't happen very often in california.

[LTDScott]

LOL, maybe this is a regional difference. I believe 50Proof lives in Corona, CA, where it's probably 80 degrees today, and actual frost is not something he usually has to deal with. So more than likely he needs to "de-fog" the inside of the windshield, something that we have to deal with frequently.

Or maybe I'm making incorrect assumptions!

[LTDScott]

Several times in this thread I've seen Corey say "defrost". So are we talking about "frost" on the windshield that's not clearing up or "fog" that's not clearing up?

sorry, i guess I mean defog. I can take my hand and wipe the inside of the window clear kind of(it gets fogged up again). The windows are not fogged up because of a bad heater core. Frost on the outside of the windows doesn't happen very often in california.

Ok, glad I'm not nuts. My assessment of the situation still stands. Is your A/C working?

[50 Proof]

Several times in this thread I've seen Corey say "defrost". So are we talking about "frost" on the windshield that's not clearing up or "fog" that's not clearing up?

sorry, i guess I mean defog. I can take my hand and wipe the inside of the window clear kind of(it gets fogged up again). The windows are not fogged up because of a bad heater core. Frost on the outside of the windows doesn't happen very often in california.

Ok, glad I'm not nuts. My assessment of the situation still stands. Is your A/C working?

no, a/c needs to be tested for leaks and recharged. It might not be worth it for me to fix the a/c system. I'm looking to pick up a newer transportation car so I'm hoping to be driving the 86 as little as possible (for daily driving purposes) in the near future.

[GT350R]

I don't get that film on the window when a heater core is bad,

You sure you have proper coolant levels and not a high or only water mixture? Being a cali car , I could see how it would be easy to only run water.

[LTDScott]

Several times in this thread I've seen Corey say "defrost". So are we talking about "frost" on the windshield that's not clearing up or "fog" that's not clearing up?

sorry, i guess I mean defog. I can take my hand and wipe the inside of the window clear kind of(it gets fogged up again). The windows are not fogged up because of a bad heater core. Frost on the outside of the windows doesn't happen very often in california.

Ok, glad I'm not nuts. My assessment of the situation still stands. Is your A/C working?

no, a/c needs to be tested for leaks and recharged. It might not be worth it for me to fix the a/c system. I'm looking to pick up a newer transportation car so I'm hoping to be driving the 86 as little as possible (for daily driving purposes) in the near future.

Well more than likely, there's your answer. Like I said, the A/C system is what actually removes the moisture from the window. The vent just directs it into the right place (windshield).

[GT350R]

So what your saying is that if you do not have functioning A/C your defrost will not clear your window!?!?!!?

:roll:

[5 Liter Mustang]

what about AC Delete cars... do they just suck at defrosting or what?

[Zap's 85 GT]

A/C helps but doesnt stop it from working. As long as heated air is getting onto the windshield and follows what the controls are set to then I'd say the controls are working properly.

The only thing I can think of is that there is an excessive ammount of moisture present in your car or getting into the system by some other means.

Big Question. Do you have a decent 50/50% antifreeze/water mix in your cooling system?

Even in England where only about 10-15% of the cars come with A/C the defrosters still work fine. Heat is heat. It just needs to be dry heat.

[50 Proof]

So what your saying is that if you do not have functioning A/C your defrost will not clear your window!?!?!!?

:roll:

well you don't need A/C to defog your window, however having A/C will help things defog rapidly. Without A/C you'll grow gray hair before your window clears up but it will clear up........eventually.

BTW when I put coolant in, i mixed it 50/50, no straight water. I should have proper coolant level although I do need to flush the system out, stick a hose in the block and flush that out too. When I first put the fluidyne in, I put in a t-stat too and put in 50/50 and it overheated in traffic but ran cool otherwise. So something is definately wrong with the cooling system. Probably clogged coolant passages in the block.

[Zap's 85 GT]

So something is definately wrong with the cooling system

My bet is the fan clutch is shot.

[50 Proof]

So something is definately wrong with the cooling system

My bet is the fan clutch is shot.

I have an extra fan clutch I can try. The one on my 86 must work some because the car runs cool otherwise on short distances and when I don't sit in traffic. Maybe the fan clutch isn't locking up when it should?

[Zap's 85 GT]

Thats the way my Aerostar was. Cooled fine driving but with the A/C on in traffic it would start to overheat. When I put the new fan clutch in the temp never went past half way. Sounded like a tornado under the hood too. You could tell it was moving a lot more air.

[GT350R]

So what your saying is that if you do not have functioning A/C your defrost will not clear your window!?!?!!?

:roll:

well you don't need A/C to defog your window, however having A/C will help things defog rapidly. Without A/C you'll grow gray hair before your window clears up but it will clear up........eventually.



Non of my cars have A/C (some did, I pulled it). My hair is not grey. Unless you put them side by side, you would not even notice a difference.

[Marz]

I have an extra fan clutch I can try. The one on my 86 must work some because the car runs cool otherwise on short distances and when I don't sit in traffic. Maybe the fan clutch isn't locking up when it should?

With this hot weather here in SoCal.. I've been thinking that my fan clutch isn't working the way it should too.... I have an Autometer Mechanical water temp gauge and for the last couple of hot days I've seen that needle go up to as high as 200 - 210 Deg while driving!

Hell, my 58 Edsel gets that high but it's basically a stock 50's car (w/a 180* stat and 3 row radiator)... and I can understand why it would get hot.

It's an 85 GT 4bbl 5 spd with an 86 shroud, coolent catch bottle, fan and clutch. I don't think theres a real difference between the 85 and 86's... should cool the same. And the guy I bought the car from says he tossed a 180* stat in it.

I was thinking off tossing in a new Modine 3 row, Milodon pump and high flow 180" stat, and a new fan clutch and see what that does. and if that didn't keep it cool I was going to toss in a Black Magic Electrick fan from MM for better cooling and a HP gain.

Sorry for hijacking your thread 50 proof...

Also, I've always thought that a good new fan clutch is supose to be a bit tight... you know... not very loose.

[noslofiveoh]

maybe u have trapped air in ur cooling system? have u drilled a burp hole in the t-stat....i dunno if u need one on a ford but my old chebby i did