H3 I5 power steering pump comparison.

[rascole]

Since my SAS I recently started to have power steering pump whine after an hour of wheeling. On the street and highway everything is quite but as soon as there is constant demand on the trail, the howling starts. Clearly the FJ80 box and PSC ram assist are too much and the fluid is getting hot. I installed this current pump in 2019 so it is relatively new and few miles. I’ve been chatting with someone from Radial Dynamics and first thing he said was get the biggest cooler and think about an aftermarket pump. So it got me thinking. Because the H3 PS pumps and reservoirs are getting scarce, I thunk outside the box. With the H3 being a close cousin to the Colorado and Trailblazer, I decided to do a side by side comparison. I bought a Cardone reman for a 2006 H3, Colie and 4.2l TB. The H3 pump is very similar in construction but differs In a few ways.

• Rear assembly for the Colie & Trailblazer use a snap ring to hold together, H3 is a bolted body for higher PSI I presume.
• Pump cavity on both is notably smaller so GPM is clearly lower, PSI might be the same though. TB is slightly larger than the Colorado.
• All the pump castings share the same 3 bolt mounting but each housing is slightly different. All 3 bolted up to the H3 with no interference.
• Pump vanes are smaller most likely due to lower flow and pressure demand.
• Pump shaft is larger on the Colie and TB so a H3 pulley will not work.
• Reservoir is slightly larger on the Colie and huge for the TB, H3 inadequacies are real.
• All the reservoirs’ mounts are different so they are not interchangeable with each other.

Over all the Colorado/Trailblazer complete assembly will work if you are desperate and might even last on a street driven H3.

From left to right. H3-----Colorado-----Trailblazer

 

[rascole]

Colorado pump vanes. Smallest of the bunch.

 

[rascole]

Trailblazer pump vanes, slightly larger.

 

[rascole]

H3 pump vanes.

 

[rascole]

Colorado pump installed.

 

[rascole]

TB pump installed. Tight but it clears.

 

[rascole]

Colorado vs H3 pump.

 

[alrock]

Geek!

Awesome comparison. You are correct with the H3 power steering components. The AC Delco pumps are nowhere to be found. All of the other pump sales are without reservoir or pulley. The pulley is not available anywhere. Do NOT lose or damage that pulley if you are replacing your PS pump.

 

[cgalpha08]

Randy,

I have also noticed the hot fluid, like so hot the pump will burn you within a half second hot. I installed a pass through heat sink cooler and that seems to help to a certain degree.
Since i have the v8 i can run other accessory brackets made for LS motors and have a bracket sitting the the garage that will run let me install a PSC pump and a remote reservoir, and thus a massive cooler up front.

Have you given any thought to trying to run something similar on the i5? it shouldn't be too terribly difficult to get a bracket made up that has the spacing right to let you run a psc or some other aftermarket pump. More pressure, remote reservoir, big a$$ cooler.

 

[rascole]

Randy,

I have also noticed the hot fluid, like so hot the pump will burn you within a half second hot. I installed a pass through heat sink cooler and that seems to help to a certain degree.
Since i have the v8 i can run other accessory brackets made for LS motors and have a bracket sitting the the garage that will run let me install a PSC pump and a remote reservoir, and thus a massive cooler up front.

Have you given any thought to trying to run something similar on the i5? it shouldn't be too terribly difficult to get a bracket made up that has the spacing right to let you run a psc or some other aftermarket pump. More pressure, remote reservoir, big a$$ cooler.

Yes, working on that this week. I will add pics when I am done. I am adding a 18" finned aluminum cooler. It will add 24 ounces of fluid, which is a lot for the I5 and it will be mounted on the new cross member Steve made for the front of the frame behind the radiator. Perfect spot.