Recommendations for a glass cleaner that works?

[Durenol]

If you have a heater core leak, a slight one, you will get a hard to clean film on the glass

Errgh... not what I want to hear. Is there a way to test for this easily?

[prwood]

For a cleaning cloth I recommend microfiber. Harbor Freight has a wide assortment of cloths for cheap. Just throw them in the laundry afterwards:

https://www.harborfreight.com/catalogse ... microfiber

[prwood]

If you have a heater core leak, a slight one, you will get a hard to clean film on the glass

Errgh... not what I want to hear. Is there a way to test for this easily?

Films like this can also be caused by the evaporation of Armor-all type cleaners that were used on the dashboard. When I realized this, cleaning my interior windshield with alcohol took care of it.

[Durenol]

Films like this can also be caused by the evaporation of Armor-all type cleaners that were used on the dashboard. When I realized this, cleaning my interior windshield with alcohol took care of it.

None of that stuff has been used on this car for at least a decade if ever. AFAICT whatever this hazy film is it's from the car itself.

[mrbrian200]

Films like this can also be caused by the evaporation of Armor-all type cleaners that were used on the dashboard. When I realized this, cleaning my interior windshield with alcohol took care of it.

Thats what I meant by 'detailing sprays'. There's usually a bit of overspray from the squirt bottle that hits the windscreen or transfers from your towel accidently then gets smeared all over next time you clean your glass. Some of these products use silicone oil in the mix to get a glossy finish on you dash.

A friend had a pesky film on the inside windscreen of his Civic about a year ago. Like OP, nothing we tried was picking it up. It just smeared around. In the end what finally got rid of it was alcohol and about a full roll of paper towels. Seemed each towel would only pick up a tiny bit at a time, then smear the rest around. Microfiber cloths would sort of just grab at it but leave it in place with a 'texture' that in direct light looked like somebody scuffed the glass with steel wool. We spent about a half hour+ buffing and cleaning it off. He seemed to think the pesky film came with the car when he bought it new about a year prior. He'd tried to clean it off with regular window cleaners to no avail and eventually asked if I knew something that would take it up. I had a similar experience when I once mistakenly tried rainx anti-fog on my own car.. and learned my lesson. It's some form of silicone according to references found via search engine.

[E Showell]

+1 on possible heater core leak. Do you have a maple syrup smell in the cabin? If so, time for a new heater core.

[Durenol]

In the end what finally got rid of it was alcohol and about a full roll of paper towels.

Yeah that's pretty much what seems to have finally worked for me. I bought a bottle of 70% iso as that was the strongest they had, and it took about a dozen wipe/dry cycles before I stopped seeing any hazy residue. For future reference: I found that even the alcohol left something of a film behind, but having the cabin fan on max with windshield-vent-only the whole time helped evaporate it quickly before it could leave too much. Although now that I've done all this it reveals how scratched up the outside of the glass is from the wipers after all these years.

[Durenol]

+1 on possible heater core leak. Do you have a smell in the cabin?

Not noticeably, although I mean the car always smells like "car" faintly so maybe there's something mixed in there I'm not really aware of. Is there a more definitive/analytical way of testing for a leak?

[abscate]

You can pull it out and look, in which case you replace the orings anyway..the most common leak cause

[E Showell]

I edited my post to add "maple syrup" before smell. I also react to coolant, as in sneezing, so those work as diagnostics for me.