Boberino

My windows keep fogging up! By that I mean they get this film on the inside. I clean them and a day later they are getting foggy again. It is not condensation. It is clearly a problem I didn't used to have. Anybody have an idea? Someone suggested the heater core, but I don't know if that is it or not. A/C works great, heater works great.

It's an 88 with 151K (5K on new engine). It is driving me crazy. It makes passengers wonder why I don't keep the windows clean...

NRA T2

spray de fog on them

Icemark

Yep, pin hole leak in the heater core.

Boberino

Great... And I understand it is a bitch to R&R the heater core on a 2nd Gen?

silverrotor

iTrader: (1)

Time consuming more like It.

I found when I swapped out my Interior that the Dashboard was the most time consuming. I was worried more that I was going to break a plastic part or yank a wire out more than anything.

Removing the Dash will reveal the guts of the Heater Core.

scathcart

You could try some RAIN-X anti fog (an alcohol product that prevents fog from forming) until you have time to tackle the HC.

bingoboy

in other cars i have worked on (not rx7s) an immediate fix was to bypass the heater core. in one of the cars we just left it like that.

now im not sure how the heater stuffs are setup on rx's of if its a good idea. maybe someone can help on that.

and how well would rain-x work on that...if its the heater core wouldnt it not be water thats fogging? the fog would have a coolant/antifreeze film wouldnt it?

autocrash

yeah, Rain-x antifog is not gonna help with the film situation, but it may remove the need to use the defogger in the first place (no defogging = no film on windshield!)

Maybe thats what scathcart et. al. meant...

I'm interested in the heater core bypass too... anyone got more info?

Hephaestus

Boberino, you DO have a leak somewhere in the heater system and it's venting the coolant into the dash, windows, and under the floor carpeting. the next time you get in the car check and see if there is any moisture under the carpet. You'll need to take care of this pronto because left un-fixed, you're asking for a rotten smelly interior

O.K., I have a 1988 GXL that had the same problem. the quick fix is VERY easy if you have the tools/ parts. The time is only about 30 minutes once you're set up.

go to the auto parts store and buy the following:

4 feet of 5/8" insulone heater hose (buy the black hose, it looks better). cost: about $8 to $12.

Rubber bypass plugs (brand name is "FIXIT") I think you get 2 in a pack. thats all you'll need. cost: $1.89 +tx

2 metal heater hose fittings to connect the new piece of hose. ("FIXIT") get the straight ones, not the "T" ones.
cost: about $2-$4 each.

a pack of stainless steel hose clamps 3/8" to 5/8" range
cost: about $3 for a pack of 4.

a sharp knife.

screw driver/ basic tools.

Now. open the hood of your car. look at the fire wall just behind the top of the engine. on the wall you'll see 2 black rubber hoses going into the fire wall spaced about a foot apart. these hoses are going into the heater core. The hoses lead from the heater core on one side and then out to the engine on the other side. caution: do this only when the car is cold!

undo the clamps at the fire wall and remove the hoses. If the hose is old (like mine was) you'll have to cut them off with a sharp knife. Cut them just forward of where the clamps were. Now remove the remaining hose on the fire wall by hand.

drain whatever fluid out of the 2 pieces of hose that are still attached to either side of the engine. The hoses are far too short to reach each other due to their placement on the opposite sides of the engine.

This is where you need the extra hose. Measure out about how much hose you need to get the 2 pieces to reach each other, cut the hose as cleanly as possible. Next take the metal hose fittings and put 1 into each end of the new hose. Clamp the fittings into place. Possition the new bypass hose near the fire wall just under the heater ports where you cut the old hose from the fire wall.

Fit the other ends of the new hose fittings into the old hoses on either side of the engine. (make sure you have the other clamps ready incase the old ones are no good). Clamp them down tight. The bypass is now done!

Next, flush out the remaining coolant out of the core. use a garden hose or compressed air on one of the fire wall ports and blow out the fluid. Use something to catch the fluid to prevent a mess.

Plug the exposed fire wall ports with the rubber bypass plugs. It keeps contamination down to a minimum.

Start the car and check for leaks. Whew! thats it!

By the way, I hope you understand that the heater will never get hot after you do this. the fluid will just recirculate back into the engine and not go through the heater core.

bingoboy

any idea how much the heater core weighs? like would it be worth removing for the weight if i had nothing better to do

autocrash

lol.. heater cores are pretty bloody light... (it's like a radiator, only smaller) so maybe about 1/5 the weight of a radiator)

Boberino

1) If it truly is a pinhole leak, which it could be, as there is no dampness under the dash board, would a commercial leak stop product work?

2) I hate the idea of removing the dashboard. How likely I could R&R the Heater Core while the dashboard is in place? (No laughing, please...)

JumpyRoo

I'm afraid it's pretty unlikely, I'm doing the same thing myself. BTW, picking up a new heater core isn't easy. It's pricey. I was going to get one used, but I don't want to do this swap more than once in 100k miles, so I'm laying out a hundred bucks for one that works right and is at least garunteed, which is a word I could never spell correctly.

OC_

if you use silcon based polish on your dash or somthing like armorall, it can transfer to the windows and make them do the fog thing. Since they have a silcon base, they are very hard to clean off.

Boberino

Thanks everyone - I appreciate the input.