My Dewalt emglo D55141 does not shut off. It keeps running past the 150 psi max and blows out the PRV. Is there something I can fix that will cut out air pressure like supposed to?

SOURCE: Dewalt D55168 air compressor runs until 95 psi and

If you have no leaks the first thing I'd check is the ring and cylinder for wear. The cylinder wear is usually pretty obvious, but if you can see light around the piston ring it's bad. The replacement part number is N038785. Also check to make sure no valves on the valve plate part number A09819 are broken or bent.

SOURCE: air won't go past 40 psi on my dewalt compressor

If it keeps running, but doesn't gain any ground, and you don't have significant leaks, it's either piston rings or (probably) valves. If you're up to it, pull the head off (mark the valve plate orientation with a sharpie marker, first). Look for broken or fouled valve reeds or discs (depending on design).

Marc Powers

• 146 Answers
• Posted on Oct 13, 2010

SOURCE: I have a dewalt D55168 air compresser. motor stays

Here is a parts diagram for the air compressor:

http://shoppingcart.msservicecompany.com/msservice_net/product_files/D55168/D55168_PL.pdf

There are a couple of things to look for on the air compressor.

You will need to see if the piston ring is damaged or if you have a broken reed on the valve plate.

These are typically the two most common problems with this model.

SOURCE: It is an electric motor Dewalt Emglo Compressor

Dewalt recommends using synthetic pump oil, however if you only use the machine occasionally and not in a commercial setting, standard compressor oil will work great and save you money. Synthetic oil will last longer and can take much higher temperatures without breaking down. Lowes sell the kobalt brand of compressor oil and sells for about $3 for standard and $7 for synthetic. Home depot sells campbell hausfeld brand but equally as good. Auto parts stores also sell a line of compressor /pump oil just watch pricing for your needs. If you can't find compressor oil, non-detergent motor oil works just fine. Good holidays

SOURCE: dewalt air compressor keeps running until pressure

The regulator switch/unloader is bad or out of adjustment. Perhaps though the gauge is faulty. 200 psi in a 120psi compressor is dangerous, don't run it until it is fixed!