Calling all mechanics!!!

[EJ3]

So I bought a truck.

The seller told me the a/c doesn't work because the refrigerant slowly leaks out and he never bothered with fixing it. I understand that there is some additive that can be put in while recharging the a/c system so that when it runs out next time they can find the leak with special glasses and light.

Air blows out the vents fine, but I also found out that the heat doesn't work either. I have not tried to turn the a/c on to check the compressor or anything since I do not know much about it and don't want to damage anything by doing so.

I would like to get both the a/c and heat working. Does this sound like an easy fix or something quite involved and/or expensive?

I only use this truck as a tow vehicle. A/C and heat would be very nice but not a necessity.

Advice! Help! Opinions!

 

[Bass Man Bruce]

Re: Calling all mechanics!!!

Check the fuse for the fan first, would affect both if blown.
Does the fan work? If not look for fuse/relay/resistor and ck them. If all are ok ck fan to see if it's getting power.
If fan works and still no heat ck heater core for coolant flow.
Good luck.

 

[Windykid]

Re: Calling all mechanics!!!

What year and model truck?

 

[EJ3]

Re: Calling all mechanics!!!

1994 Ford F150 5.0L 302...

Your right, that would help!

Air blows from the vents, just not hot and cold.

 

[jmoorepghpa]

Re: Calling all mechanics!!!

Involved...just some detective work. Expensive - probably not for a '94. Try a couple things first and post the findings. 1- do you hear the interior doors/flaps move inside the cab and does the airflow change direction appropriately when you switch from heat to a/c. Do you get full air flow... does it blow as much air on high as you would expect? 2- when you cyle the ac on and off do you hear and see the clutch on the compressor click on? 3- are the heater hoses hot at the firewall after the engine warms up? Does the engine warm up? Let me know. You could actually have seperate problems. A leak in the freon system is reasonable for a '94. You could have a duct/damper control issue inside the cab. You might have a clogged heater core or a stuck open thermostat. The electronic control panel in the dash can also be suspect. You have to do a little investigation but it will work out we just need to start getting some info into the process here. Let us know.

 

[EJ3]

Re: Calling all mechanics!!!

Great, thanks!

I will run the tests and post results.

 

[Gary H NC]

Re: Calling all mechanics!!!

Make sure both heater hoses are actually still hooked up going into the firewall.Some people bypass them rather than replacing the heater core.Lets hope thats not the case.
The AC will not kick the compressor in if the freon is low.Don't worry about hurting it.
They do make freon with dye in it to help locate leaks.

 

[Bob_VT]

Re: Calling all mechanics!!!

My old ford used to leak slowly and every year I would just recharge it ..... I had converted it to r-1342a so the walmart cans were cheap. It was an annual ritual.

Inspect the steel lines and look carefully at the ones with rust.... more than likely they are the leaker's.

If you charge it with r-134a it will either work or not. Once there is fluid in there you can bridge the compressor switch with a paperclip to see if it is actually working.

 

[whywhyzed]

Re: Calling all mechanics!!!

....

 

[NeverEnough02]

Re: Calling all mechanics!!!

In most cases it will be the blower doors. I am not sure where they would be on that model. They are usually deep behind the dash or in front of the firewall. That truck might have an air filter for the pushed air too. Those are usually dirty. In fact I never changed mine! Its not smell though... I had a 4.6 ford and the ac compressor **** the bed. If this is the case, a junkyard compressor will be your best bet as a new one will be worth more than the truck. Once you find it, hit it with a hammer while the ac is on and motor running. If the clutch catches and puches some cold air.. you know what the issue is for the AC. They frequently sieze up. Mine was a 94 as well. (Lincoln) so it could be the same part.

 

[NeverEnough02]

Re: Calling all mechanics!!!

Your dial could be dirty too. Pull that and use electical contact cleaner. If the contacts are worn threw, get a new one at a salvage yard.

 

[SS MAYFLOAT]

Re: Calling all mechanics!!!

I personally hate those dyes. I would rather buy Cliplights product for sealing refrigerant leaks than waste the money on the dye. Charge it, seal it, and your done. I've used this stuff in commercial applications and it works. There are different doses for different needs. There is one just for automotive applications as well. The only draw back to this stuff is once the system is opened and has air intrusion, the stuff will harden in the lines. All that is necessary to prevent this is to cap both ends of the line when removing them. I ran it thru my manifold/guages and it clogged them up. I'll never do that again.

As for the heat, make sure your coolant level is up. A low coolant level will not give you any heat either.

 

[Caveman Charlie]

Re: Calling all mechanics!!!

No filter on that truck. I have a 95 F-150 5.0 myself. These are still the old squared off style truck. Purty simple HVAC system. There may be a cable going from the hot cold knob to a valve under the hood that shuts the coolant flow off when you turn the know to cold. Make sure that is still hooked up and working . Might be a vacuum line instead of a cable. I have to do chores soon I'll try to remember to look on my truck.

 

[Caveman Charlie]

Re: Calling all mechanics!!!

I looked this morning. There is no shut off on the heater core like I thought there was. That must have been on my old truck.

 

[NeverEnough02]

Re: Calling all mechanics!!!

ahhh! I forgot the trucks stayed with the 5.0 for a while. Figure out whats wrong yet?