The Keihin HS100R Scroll AC compressor

Howdo~;) dne’ here,

It’s raining here, so not a bad day to put information out on Classic Cars and Tools!;) The following is not about a classic car, but about an AC compressor that seems be causing a great deal of grief!

This blog is about the Keihin HS100r scroll AC compressor used in 2002-2007 (give or take a year) Honda CRVs and maybe some other vehicles. I found out about this compressor after purchasing a pre-owned 2002 Honda CRV with 79k miles for our youngest daughter. Being a Honda, I figured I couldn’t go wrong!  Anyway, this blog may be more interesting to folks owning a Honda CRV of the year model specified, but probably rather boring if you don’t own one! But if you know someone that owns a Honda CRV between 2002-2006, you may want to point this blog out to them!;)

 

In short, the AC compressor locked up within 100 miles of owning it!:( However, I’m no an expert on this particular compressor, but thought maybe some good folks out there might like to know a little about this AC compressor. Again, I’m not an expert, but have great common sense and love to know what makes things tick! On another note, some folks may be fortunate and never have a problem, so lucky them! 😉

 

 

Henceforth, this blog is only about the compressor! Removing it and other AC components on this particular CRV will soon be discussed on other blogs on this site. This is just my observations and my own personal comments on this compressor for now. If someone out there is a pro and would like to include his or her comments based on first hand and Tech experience~ I can include those as well.

 

First off, the compressor sits low on the transverse engine front right just below the alternator and power steering pump. It’s not in an accessible area to service, much less to even look at it. It also does not have much air flow to cool it other than the heated air coming through the radiator. Keep in mind, the high side line gets really hot, so one would know that the internal temperature must be superheated. The 4.5 ounces of PAG46 refrigerant oil is its only means of lubrication, which can also carry contaminants (byproducts of wear and tear) throughout the system, but the evaporator may be somewhat protected by the AC dryer/filter, but the expansion valve may not be so lucky!

 

 

 

 

The compressor is bolted onto the engine block by 4 long 14mm bolts. The picture below is of the engine side of the compressor. However, the lower bolts bolt into a bracket which itself is bolted to the block

 

 

 

Measuring here, I was considering fabricating brackets to accommodate a Sanden compressor, but I really need to get this SUV back on the ground, so when it breaks again, I’ll consider that option next time.

 

 

 

 

The HS100R compressor next to the Sanden compressor on my 59 Chevy truck.

 

 

 

 

With the AC compressor dismantled, the next 4 pictures show how the two halves of the scroll and how they articulate together.

 

The silver or aluminum piece in my hand bolts to the back portion of the housing by 4 bolts and is stationary.

 

 

 

 

 

However, the darker colored part, the part that seems to self-destruct oscillates and probably turns at a great RPM.

 

 

 

My observation here are the tolerances are very close and no room for error, if tolerances become out of whack, then destruction takes place.

 

 

 

 

Compressor CSI! 😉  Identifying the culprit or at least ideas of what may have gone wrong!:(

The scroll portion here is the moving, or on an eccentric oscillating assembly. I can only imagine how many RPM’s it turning, not to mention the pressure it’s producing and heat being generated, and only supplied by a small amount of PAG46 refrigerant oil which is circulating throughout the AC system!

Here the pieces here are put back in place to observe.

 

Perhaps breakdown of the refrigerant oil, combined with extreme heat, tiny particles, and fatiguing bearings, the tolerances point towards, something is going to collide! Then only takes tiny fragment to get in between two seeming rigid structures, then, WHAM! That’s all she wrote!

 

 

 

So, then the broken parts shear from the base of where the were formed therefore rocketing fragments throughout the AC system.

 

 

This is the stationary part of the scroll. It is held by four bolts and does not move. Take note of the swirling marks.

 

But notice the shiny swirly marks produced by the oscillating scroll? Just a fraction off tolerance, and thar she blows, something has to give!

 

The center part is a flap valve of sorts, maybe the high side port?

 

 

Backing up a bit. Before one gets into an AC system, unless the compressor actually blew and launched its contents into the atmosphere, the 134a refrigerant needs to be recovered! This can be either done by a local shop or you may have your own AC reclaim machine like I do. Otherwise, one should not release refrigerant into the air. Of course always were safety glasses, and don’t let the refrigerant oil get on the paint!

 

 

 

Fortunately, my system still was intact of containing its contents, therefore contents could be successfully reclaimed. My Whites Industries machine only reclaimed a little less than an ounce of refrigerant oil! The system recharge of oil is 4.5 ounces! I may have recovered another ounce from the condenser, evaporator, desiccant, and other areas, but definitely not 4.5 ounces! I could find no other oil.

 

 

So this isn’t so much about the compressor, but this is the filter/dryer/desiccant. Mine caught some nasty looking stuff!

 

As said, this is my observation of this particular compressor. If I knew what actually happened, I’d be on the cover of some magazine as the woman who solved a problem! However, I would say that the refrigerant oil is the life of this compressor especially since it gets very little air flow to cool it. I’d have to go on to say it may be beneficial to have the AC system, say every 50,ooo miles, serviced by removing the refrigerant and refrigerant oil by means of a good AC machine and a good shop that you trust. Perhaps even have the desiccant/filter replaced as it catches small debris too. This could postpone an expensive repair bill and keep your AC system cooling like it should! That’s what I plan to do after I repair my system.;)

I hope this has been a little educational. I do plan to put my repair work from my 2002 Honda CRV after I’ve got it completely back together, which should be later next week. Until next time! dne’

If you found this helpful, please make a nice comment;)