Hi: Just read the FAQ about replacing a leaking heater core. I was hoping someone had a possible alternative solution to my problem or a way to confirm the problem.

My 91 940SE turbo wgn. with ECC system. It will fog the windshield no matter what climatic control settings you select.
Outside temps are now 55 F outside so fogging is odd. No error codes. All seems to operate properly except the AC but I removed it (It needs basically a whole system, previous owner was lax). I have a bit of weeping at the rubber seal on top of waterpump. No AF on the floor inside the car. A very faint AF smell in the car at rest. Don't notice anything w/ the car moving.

The fog really doesn't seem to be sticky enough for AF. It leaves slightly more film on the inside of the windshield than just water vapourwhen you try to wipe it off.

So is it possible to have such a small leak that fogging will occur w/o seeing
leaking on the floor?

Any similiar experiences? Any good prices out there for heater cores?

ibs740

Fogging can occur with only slight leaks that don't show up much on the floor until they enlarge. Have you tried a cooling system pressure test?

Yes, I started at 20psi it bleed down to about 16-17 & held that. That was when I saw the weeping on top of the waterpump at the rubber seal.

A leaking heater core should allow pressure release down to zero over time. I suspect that you've got a developing leak, but have no need to change it out now. Get a core and plan on a Fall weekend to fix it.

Thanks. Any good quality sources other than the dealer?

Four Seasons is a good brand. Usually the local NAPA stores have good quality stuff.

AS Steve says get the core and replace when so inclined. In the meantime if leak increases it easy to bypass water flow through the core by rearranging the plumbing at the vacume operated heater valve, engine side of firewall, driver side.
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David Hunter

AS Steve says get the core and replace when so inclined. In the meantime if leak increases it easy to bypass water flow through the core by rearranging the plumbing at the vacume operated heater valve, engine side of firewall, driver side.
--
David Hunter

I was planning to put in a shunt tube now that I know how much fun this is to fix.

Thanks