Using Brake Cleaner in Engine Compartment

I find the CRC QD electronic cleaner to be effective at cleaning, and safe on all surfaces under the hood. I don't hesitate to use it on any surface without issue including rubber, plastic, painted, gaskets, etc.

 
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I have and will use it, Just keep it away from plastic/rubber/painted stuff. I wouldn't use it in your application.
 
I am somewhate of a Brake Kleen aficionado...love it. But yes, probably not the best thing to go crazy with on rubber/plastic etc and can damage clear coats on wheels etc. I use it on the undercarriage a lot.
 
I got CRC 2-56 and QD contact cleaner mixed up! QD will not harm plastics but will freeze electronic components as I have said.Sorry if I caused any confusion. I use it all of the time at work for sensitive electronic and electrical assemblies.
 
While checking the oil this morning, I noticed a little oily residue on the hose coming from the power steering reservoir. I don't yet know if it's a minor leak or just some sloppiness left over from the last fluid change. I have some brake cleaner handy ... can I use it to clean the oily area on the plastic reservoir and hoses ... will the cleaner cause any damage?
For rubbers I usually check "rubber compatibility" charts, there's a good one here: https://www.minorrubber.com/compatibility-chart.html

Brake cleaner is usually perchloroethylene or tetrachloroethylene, both of which has mostly unsatisfactory ratings against most rubbers, especially the kind they use under the hood these days which is EPDM. That said, I've used brake cleaner on lots of rubber brake parts, boots and the like and hoses too without ever having an issue, plastics too. If the engine bay is hot or you do it in direct sunlight it's going to speed up the chemical reaction so that provides more opportunity for "damage" in the same timeframe cold. About the only thing I don't use it on is painted and powder coated surfaces like the subframe, it tends to soften and dull those (but you can usually make them shiny again using another solvent mixed with oil, like WD-40).

70% isopropyl alcohol put in a $1.50 spray bottle from Walmart also cuts oil residues extremely effectively without leaving any residue, (as long as you get one that isn't green with added mint scents or whatever) and is far less harsh if you're worried about that. On the chemical resistance chart it has A ratings on nearly every type of rubber.

If you're concerned do it when the engine is cold, use isopropyl or use the brake cleaner but spray it on a shop towel and do brisk passes over the surface, dousing it with brake cleaner and letting it run off is a waste anyway. I don't exactly know what test regimen they use for the compatibility chart, their ratings may be derived from the rubber being in constant long-term contact with the chemical (like a hose containing the chemical) which is different than brisk passes over a period of a minute...
 
I use green CRC brake cleaner for two things only, clean brake components and as starting fluid in the spring, for my lawn mover and gen set.

I wouldn't use for anything else, and definitely not on rubber / plastic parts
 
Brake cleaner is a very harsh solvent. For oily residue, especially oily residue on a rubber hose, I would use a degreaser product as they are designed to remove oils and are less likely to have an adverse effect on the rubber hose.
 
I have used brake clean to clean pine tar off a chainsaw. Took off the tar, and the paint too.

I will never use brake clean again on any painted surface.
 
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