Help with heat exchanger clean procedure

[pszemia]

Hello everybody, i have all the engine parts clean and ready to assembly but, my heat exchangers (stainless steel) looks very dirty.

On the outside is a mix between dirt, years and oil. In the inside is spread with oil (beacuse of leakage from old valves).

My question is, how do you recommend to clean the outside and the inside of the exchangers?


Thanks,

Ariel

[Bob Kontak]

Take them to an "old" car radiator repair shop and have them hot tanked. It will melt the oil and it will be very clean. Also, inexpensive.

My 81 heat exchangers appear to have a gray coating on them. The outside sheet metal. I do not know if older ones have this as well. I am not sure if the hot tank process would remove this or not. The heat probably would not but the chemicals may.

[skrufy]

Ditto the above. A radiator shop would be my first stop, but many auto machine shops have hot tanks as well. The caustic solution will remove everything, including the old gray paint on those '81 heat exchangers. When done, even though they have rinsed them, I'd do it several times at home with soap/water. I'd use a solution of Simple Green, or something I like even better- ZEP Citrus Cleaner available at Home Depot- nicer smell. Any residual smell inside the heat exchangers will come into the car when you turn the heater on. It will probably do it anyway after multiple rinsings, so open everything up- doors, windows, etc at home and just let the engine run with the heaters on to bake out the smells......

On those '81/similar heat exchangers, use a high temp HEADER paint on them, not just 500 degree engine paint IMHO. When I repainted mine with engine paint, the nice even paint job got discolored quickly around the exhaust pipes.....

On those stainless steel exchangers, after the oil/grease has been removed, you will find all the nicks/pits of road rash. If you want to take the time, you can wire brush the big stuff with a drill, then take fine wet/dry sandpaper- 800-1000grit, and sand in one direction with water to get a satin finish like on a stainless steel refrigerator. If the exchangers are now nice and shiny after hot tanking, you might not want to wet sand
them at all. Just some ideas on detailing- your preference......

Tim

[pszemia]

Thanks for opinion guys.. i think i will hot tank it.. and see how it looks...

[Tidybuoy]

I've used easy off oven cleaner and it gets parts spotless. I haven't cleaned heat exchangers but I've used it on transmissions and they come out looking like new.

944 Auto-Trans after using easy-off oven cleaner. This trans was filthy when I started.



Before cleaning:

[geoz]

nice! i will remember that.