hey bricknuts!

here’s the scoop. the car has had a tranny flush a few months back, and about a month ago I had a coolant flush, but I think it was more of draining the old coolant and just adding fresh coolant/water mix--not the stick a hose and shoot water type of flush. I checked the atf the other day and see that the level is up to par and the fluid is pink, not a bright red like you would see from the bottle, but it’s more of a pale red on a white napkin (is this a normal color). The coolant reservoir has been consistent in level, just a bit below the max line and staying around there. the atf level has been consistent in level too, I think.

so today I decided to check the coolant reservoir to see if there is any reddish/rusty-colored oily film floating on top of the coolant and concentrating on the inner walls of the reservoir. when I got the car about two years back, I remember the coolant reservoir had the above inside, but I didn’t think much of it, as I thought it might be green and orange coolant mixed together. well, after having a tranny swap last november and getting a coolant flush to rid the cooling system of this red film, I thought the reservoir would remain green. I remember after a week of draining old coolant and getting new coolant, I checked the reservoir and see some of the reddish film floating on top of coolant. I thought it might be some residual stuff, so I ignored it. however, today when I decided to check up on it (after a month or so of driving around), I see that there is that same reddish-rusty oily film coating the top of the coolant, and unlike before, I couldn’t see any green this time until I stirred the tank. The reddish stuff is oily, but I can’t tell what it smells like.

so, bricknuts, please help me, as I am getting this sick feeling. here’s the info I can provide:

1. coolant level does not seem to increase or decrease in the reservoir
2. atf is dark pink/pale red, does not smell weird
3. volvo radiator is original (not steel)
4. I don’t think it’s oil, as it has a tint of reddish hue.

Here’s what I think (and would prefer to think):
5. could this rusty oily stuff be some kind of radiator sealant that PO put in?
6. if some among you think this rusty oily stuff is atf (I dread this diagnosis), could it be residual atf from a previous repair?

I got a turkey baster and siphoned some of the coolant along with the oily film. You can see how the rusty oily film covers the coolant below.



sorry about this long post, but any help is appreciated. I’ve heard of atf leaks into the cooling system. I hope it's not an atf/coolant problem. is it only an “atf into the coolant tank” or “coolant into the tranny” or either way? thanks.

edit to add: how safe is this for my engine with this oily stuff in my coolant. it doesn't seem to mix with it, just collects and floats inside the coolant reservoir.