packfancjh said:
We've had decent luck with soaking them in a good degreaser for a while. Keep changing the water and use the hottest water you can get. It works well if you take the 2 ends off to open the whole thing up.
Chris is the only one here who nailed it right.
The exchanger is predominantly clogged with a mixture of dust/dirt, and the product you used to protect the blower lobes from rusting, e.g. WD-40.
Vinegar isn't going to do much of anything. What is needed is a hot degreaser soak and pressure washing, AFTER you take the ends off (drill out the rivets).
We've cleaned many
CDS salsa heat exchangers and
Boxxer exchangers of the crud that fills them up. Some get so bad, it takes a couple of days and a few man-hours to clean them up. It sometimes takes a bit of soaking to loosen up the oily/gummy mud so that you can push it out with pressure. Some suppliers simply replace them, and I can see why. But (knock on wood), our location has been able to save them all.
All of HM slide-ins now feature a port to measure back pressure, so that you can identify a partially obstructed exchanger long before it gets critical. As a result of testing, you can clean them up before they get difficult to move the degreaser through the fins.
A radiator shop is rarely going to understand the problem and/or be equipped to clean them. They are much more used to cleaning coils and fins from the inside of deposits more akin to mineral or chemical build up, in which they will use heat caustics, rather than heat, pressure & detergents to make soluble the caked deposits.
