evaporator problem

[wade]

hi guys, been having a issue with the air volume on my 88. all the controls (electronic) work as per the shop manual, my problem is air flow, there is very little. the blower is working as it should and so is the contoller. i pulled of the blower last night and stuck my hand in where the evapoator is and to my surprise pulled out gobs of heavy oily and grease that are plastered all over the evap coils, thus blocking all the air flow, iam actually surprised that it works at all given the amount of crap thats in there.... WHAT WOULD CAUSE THIS?
is it cleanable or do i need a new evaporator? my 2nd issue is that while i was trying to split the 2 halves of the evap cover, i broke the welded nut off inside the frame of the upper support bracket that goes from the hood release bracket to the frame. do i need to get this support off to get the evap out or at least get exposure to it? the lower frame is sealed and the nuts that are supposed to be welded on the frame are factory round, no edges for a wrench even if you could get one in there, so now the two bolts spin freely and i cant get this bracket off...HELP!!!!! any ideas?

 

[Hrtbeat1]

Its actually pretty common for vehicle A/C units to "gunk" up. Between the heating /cooling and condensation the road grit and grime just sticks to the condenser coils. If you have a HVAC repair/parts place near you go and ask them for the pink cleaner. Its expensive around $60 a gallon, but this is the stuff the pros use. Get a spray bottle and coat down the coils, let it sit a bit and the hose it off. Repeat and you should be good to go.

 

[scorp508]

Inspecting my evaporator for debris is the last thing I need to do for my HVAC system. I just spent the whole weekend troubleshooting it and ended up replacing the Blower Control Module. Is there a drain anywhere in the evap housing to let the "hosing" drain out?

 

[Hrtbeat1]

:duh



My bad. I was refering to the condenser (in front of the radiator.) Not the evaporator. I don't know why the evaporator would have oil and grease on the coils.

I don't think there is a drain for the evap. Sorry. Don't know if my previous method would work anyways.

 

[bill5674]

Wade; have the same problems with my 90. how did you clean it out ,and is it any better?

 

[badabing9]

:duh



My bad. I was refering to the condenser (in front of the radiator.) Not the evaporator. I don't know why the evaporator would have oil and grease on the coils.

I don't think there is a drain for the evap. Sorry. Don't know if my previous method would work anyways.

yes, there is. the evaporator is contained with the heater core in the plastic housing in which air is "blown through" from the blower motor. if there were no drain, the evaporator would become submerged and would not cool, as well as condensed water would be all over your interior rugs.

 

[badabing9]

hi guys, been having a issue with the air volume on my 88. all the controls (electronic) work as per the shop manual, my problem is air flow, there is very little. the blower is working as it should and so is the contoller. i pulled of the blower last night and stuck my hand in where the evapoator is and to my surprise pulled out gobs of heavy oily and grease that are plastered all over the evap coils, thus blocking all the air flow, iam actually surprised that it works at all given the amount of crap thats in there.... WHAT WOULD CAUSE THIS?
is it cleanable or do i need a new evaporator? my 2nd issue is that while i was trying to split the 2 halves of the evap cover, i broke the welded nut off inside the frame of the upper support bracket that goes from the hood release bracket to the frame. do i need to get this support off to get the evap out or at least get exposure to it? the lower frame is sealed and the nuts that are supposed to be welded on the frame are factory round, no edges for a wrench even if you could get one in there, so now the two bolts spin freely and i cant get this bracket off...HELP!!!!! any ideas?

if you are indeed talking about the evaporator (at the firewall), if there is a "greasy mess", that would most likely be caused by a leak (either past or present) of your evaporator coil of freon which contains refrigerant oil. the leaves most likely come from above where outside air is "mixed" to regulate temperature (so-to-speak). you may want to check the screens at-near where the wipers fold down and see if they are missing or loose to permit leaves from getting sucked down.

 

[nyernga]

A clogged evaporator coil is very possible. Especially on a car that's 17 years old. While not as easy to clean as the condenser it does get blocked up. If there was a freeon leak, yes you'd see oil on the coil but you would aslo have zero cooling. There used to be a thread on here with pics of taking apart and cleaning the coil. It even showed what the guy found in there....paper, leaves etc.

Chemical cleaning is the best way to go but just using a brush to clear the debris will help.

Len

 

[badabing9]

A clogged evaporator coil is very possible. Especially on a car that's 17 years old. While not as easy to clean as the condenser it does get blocked up. If there was a freeon leak, yes you'd see oil on the coil but you would aslo have zero cooling. There used to be a thread on here with pics of taking apart and cleaning the coil. It even showed what the guy found in there....paper, leaves etc.

Chemical cleaning is the best way to go but just using a brush to clear the debris will help.

Len

yes, i agree in part. the leak could be a past one or a very slow one at present. the rate of the leak would eventually lead to zero cooling or in it's proposed condition, assuming a "slow leak", the coils would get clogged from the mixture of the oil, dirt, grime, etc on the outside of the coils (evaporator)allowing minimal air to flow over them thusly reducing the cooling.

 

[nyernga]

yes, i agree in part. the leak could be a past one or a very slow one at present. the rate of the leak would eventually lead to zero cooling or in it's proposed condition, assuming a "slow leak", the coils would get clogged from the mixture of the oil, dirt, grime, etc on the outside of the coils (evaporator)allowing minimal air to flow over them thusly reducing the cooling.

I was assuming it all leaked out by now of course. One of my least favorite tasks is finding a freeon leak. Once you've checked the usual suspects like elbows, fittings etc it's like fishing blindfolded.

Len

 

[vader86]

If I wasnt so lazy I'd have cleaned off my evap by now as well, probably why my AC still sucks.

 

[wade]

hey guys, thought i would give a progress report. i ended up taking the entire evap out of the car(big job) it could probably be done with it still installed, but by the time you split the housing to even get at it, the only extra steps are to dis-charge the ac itself and remove the high/low pressure fittings. once it was out i sprayed the coils with a combo of varsol and spray 9, let it sit and then used a low pressure hose and it all came right out. i would not try this with high press water as the cooling fins are the finest i have ever seen, easily damaged. flushing while still on the car would be difficult as well, you would be spraying the dirt/grease thru the coils and into the heater core as well as the temp controller door, although that been said, a carefully brushed evap coil, and a shop vac would probably do an adequate job, my issue was more the grease, so it made it very sticky.....i ended up taking the
evap to a ac shop where they were able to press test it, to my surprise it tested fine, probably why i was still blowing cold air. they said that it probably was leaking at one point, but was repaired by the sealent you can buy in a can and inject into your system. so iam going to chance it and run it the way it is for awhile, took 17 years to get this bad, hopefully it will last awhile.
anyway WOW!!!! huge improvement, it was like someone had a compressor turned on.....just about blew my sunglasses of my face, i have not recharged the ac yet but will get to that soon. bit of a big job, but if you at all are suspect of a clogged, or partially clogged evap coil.CLEAN IT OUT you will be amazed at the change!!!!

 

[bill5674]

gotta tell just cleaned mine out.15 years of dirt and crap.that solved my weak air flow problem. never though it would be the simple cure,thought the mixiing doors were screwed up.a/c works great now...