Purple Power NOT safe on aluminium!

Joined
Jan 29, 2014
Messages
681
Location
USA
Hello all, I unfortunately I just found out the hard way that Purple Power is not good for cleaning aluminium parts, so I thought I should post my experience for those who don't already know this.

Long story short, I just finished doing a couple minor repairs and upgrades to my K24A2 swapped sleeper Civic (added OEM oil cooler, changed VTC solenoid O ring, changed thermostat) and ended up getting oil on the subframe, timing cover, block, aluminium oil pan, etc. While I was at the auto parts store, I picked up a bottle of Purple Power to clean my mess up since I have used it years ago with good results. With the engine barely lukewarm, I sprayed down the right side of the engine in the areas I make a mess of and let it soak for a couple minutes before thoroughly rinsing it off with my garden hose.

Once the water dried, I noticed that there was a white residue on the timing cover and oil pan. Thinking I just didn't rinse it thoroughly the first time, I rinsed it again for several more minutes but the residue was still there. After a quick Google search, it looks like Purple Power is known to corrode aluminium. I will try to get pictures of the corrosion tomorrow. Fortunately in my case the corrosion seems fairly minor and is mostly not in particularly visible areas, so it doesn't bother me much. I did, however, spend about 20 minutes rinsing off EVERYTHING in the engine compartment from every angle possible after finding out what Purple Power does to aluminium just in case of overspray, splashing, etc. Probably overkill, but better safe than sorry.

The odd thing is I have used Purple Power on aluminium parts in the past and never had this happen, but I haven't used it in years because I found another product that seems to work just as well for a fraction of the cost and is very safe on aluminium, but my local dollar store has been out of stock for a while. Perhaps the difference is that the engine was slightly warm this time, but it was nowhere near hot. I'd estimate it was probably around 100 degrees if that. I'm thinking they may have changed their formula since I never had this happen before and it smells different than I remember it smelling before, but that's just speculation.

Anyways, I hope this information helps prevent someone from having a very bad day. In my case the results fortunately weren't so bad, but I can't even imagine the kind of damage spraying down the whole engine compartment could have caused as much aluminium is used on cars these days. I'd love to hear any thoughts and similar experiences.
 

Avery4

Thread starter
Joined
Jan 29, 2014
Messages
681
Location
USA
Never tried Simple Green but I have heard good things about it. Normally I use La's Totally Awesome (the yellow stuff in the clear bottle) for general purpose cleaning and degreasing because it's $1 a quart at Dollar Tree and has always worked great for me. I know it won't harm aluminium because I have used it for cleaning wheels, engine blocks, heads, radiators, AC coils, brackets, engine compartments, etc both warm and cold and never had a problem. It rinses off pretty easily too which I like. Only reason I didn't use it this time is because I haven't been able to find it lately.
 
Joined
Apr 10, 2019
Messages
6
Location
United States
Try chemical guys invisible APC. It can be diluted to suit your needs and is quite mild. I use it at 20:1 for interiors and I’ve never had any white spots or any damage even if I forget it and let it dry on a surface. All these APCs can be diluted all the way down to like 20:1 for sensitive surfaces.
 
Joined
Jul 3, 2005
Messages
37,375
Location
NY
If diluted 1:1, it works fine for cleaning aluminum engine parts as long as you limit dwell time to a min (maximum) and only apply to stone-cold surfaces.
Yes, but I like to play it safe. I go with the Simple Green Purple Pro HD, it is safe for aluminum. I've seen a few engines and wheels messed up by people screwing up with Purple Power dilution rates, using it straight, or leaving it on too long. Purple power does work well on greasy old school cast iron engines like my Ford 4.9L.
 
Joined
Aug 30, 2004
Messages
28,158
Location
CA
Yes, but I like to play it safe. I go with the Simple Green Purple Pro HD, it is safe for aluminum. I've seen a few engines and wheels messed up by people screwing up with Purple Power dilution rates, using it straight, or leaving it on too long. Purple power does work well on greasy old school cast iron engines like my Ford 4.9L.
But is it as effective and inexpensive as Purple Power?
 
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