[AllanC]

. . . .When this 2002 caravan sits for days than starts up,when cold, sometimes the PS is late to engage for 1 to 2 minutes at most. PS Level is ok. Also... The pump does not sound until a minute or two when this happens. Otherwise its fine. . . . .

I would suspect the rotary valve in the rack and pinion assembly has developed hardened seals due to age At cold start up the seals do not flex as the steering input shaft is turned to direct hydraulic fluid properly to the internal piston to assist with steering effort. So in effect you have very hard or difficult steering due to lack of assist. After running a few minutes the seals start to flex and seal internally and then direct fluid properly and steering assist returns. In other words your minivan has "constipated steering".

The pump is not the problem because after warm up if the pump were losing pressure steering assist would be lacking. But you indicate that after a few minutes at start up steering is fine. If there was debris in the system causing blockage steering assist would be lacking even after warm up.

. . . .Should I add ATF+4 TO SLIGHTLY ABOVE the full line. Does the resevoir need service. No leaks present! . . .

You have proper fluid level. Adding fluid will NOT resolve this issue. See attached image.

 

[Aldergrove]

Thank you Allan.
When this condition worsens the rack would gave to be replaced with a new unit. This condition of impaired steering when cold only presents utself when vehicle is parked for a prolonged period of time, such as more than 5 days.

Os there an additive that can be placed in the resevroir that would target those hardened seals?

 

[Gerry G]

I would suggest replacing the PS fluid with fresh atf+4, cheaper than a new rack. The method I have used is using a turkey baster to empty the reservoir, fill with fresh atf+4 and either drive around the block or a couple of lock-to-lock turns while parked. Repeat 3-4 times for a fairly complete flush (after 2 lock-to-locks move the vehicle slightly to avoid flat-spotting the tires). There are other ways to flush that others will offer.

 

[AllanC]

. . . . . .Os there an additive that can be placed in the resevroir that would target those hardened seals? . . . .

Everyone wants a "magic elixir" that fixes seal problems cheaply. Doubtful if this will work.

 

[ImperialCrown]

Be careful here. There was a before/after recommendation in TSB #19-005-03. A different fluid may have different cold weather characteristics.

http://srt-6.com/pdf/tsb/SB_19_005_03_PowerSteeringFluid.pdf

MS-5931 is the amber P/S fluid. MS-9602 is the red ATF+4.
If the fluid isn't fresh, disconnect the lowest point of a return line, turn the steering wheel lock-to-lock to drain as much as possible. There is a non-serviceable filter screen inside the reservoir that may restrict with debris, especially when cold. The fix for this is a new reservoir.
There is a 'cold climate' P/S fluid. I've heard of it, I've never tried it:

https://cglapps.chevron.com/msdspds/PDSDetailPage.aspx?docDataId=282836&docFormat=PDF

 

[Aldergrove]

I have a new PS reservoir on order and will replace. I will purge the old PS fluid and replace with ATF+4 transmission / PS fluid. The parts counter suggested to buy generic PS fluid and add Lucas additive to the mix. Most PA fluids incorporate a stop leak ingrediant, but Perhaps I will just go with ATF+4.

Be careful here. There was a before/after recommendation in TSB #19-005-03. A different fluid may have different cold weather characteristics.

http://srt-6.com/pdf/tsb/SB_19_005_03_PowerSteeringFluid.pdf

MS-5931 is the amber P/S fluid. MS-9602 is the red ATF+4.
If the fluid isn't fresh, disconnect the lowest point of a return line, turn the steering wheel lock-to-lock to drain as much as possible. There is a non-serviceable filter screen inside the reservoir that may restrict with debris, especially when cold. The fix for this is a new reservoir.
There is a 'cold climate' P/S fluid. I've heard of it, I've never tried it:

https://cglapps.chevron.com/msdspds/PDSDetailPage.aspx?docDataId=282836&docFormat=PDF

View attachment 92715