Join the Car Talk Community!

Discussion Rules

Welcome to the Car Talk Community!

Want to ask a question or join the discussion? Great! Join now.

Sign In Register

overfilled power steering reservoir

I recently had my 91 Lincoln steering gear box replaced and the mechanic over-filled the p.s. reservoir (to the brim). I then drove maybe 400 miles and started to hear a wailing or siren type sound coming from the under the hood, which I thought might be due to the over-filled reservoir. I removed the excess fluid but still hear the wailing, siren type sound. Would a overfilled power steering have reservoir caused this?


  • edited December 2007

    There is generally no problem associated with overfilling a reservoir, any reservoir, be it coolant, washer fluid, or power steering fluid. The only reason for avoiding overfilling is that the liquid could slosh out. Do not blame the overfilled reservoir for the mystery noise, whatever it may be.

  • edited December 2007
    No, if it was all fluid; but too much air in fluid would. You might get shop to just listen to sound/symptom @ this point. Is the wailing/siren sound worse as you turn steering wheel w/engine running? Try in P or doing figure 8's in a parking lot. Sounds like the tech was too rushed to properly get air out of pow. steering system after he filled it; air bubbles expanded w/pressure & heat

    created by pow.steering system operation, increasing air/fluid volume. Anyway, get fluid level where it belongs. You want to get air out of system. Let engine idle w/cap off p/s resevoir. Have a cup of coffee and "hang out". Periodically add fluid if nec. (Take note of "hot' and "cold" lines on p/s dipstick.) After 7-8 minutes turn steering wheel lock to lock and see if your sound is gone. If no, go do a lot of fig

    8's, come back, and refill, if nec. If symptoms still there, check/add fluid. Now you could jack up front of car if poss; w/tires off ground turn steering wheel lock to lock for maybe a minute; (be safe); then check/add fluid. Go for 1 last fig 8 ride, and check/add fluid. If sound is still related to turning of steering wheel I think damage was done to p/s pump and/or steering gear by the tech not getting air out of

    system. If sound seems totally unrelated to turning of steering wheel, it's something unrelated. Or, you could have shop do the work of getting the air out of system- I'm just trying to give you the big picture. Good luck.
  • edited December 2007
    The problem with overfilling the reservoir is that as the fluid heats up and expands it is going to be expelled through the vent. If you notice on the little dipstick on the cap, there usually is a 'cold' level and a 'hot' level. So if the reservoir was filled to the brim the equivalent amount of fluid between the 'cold' and 'hot' lines would have been expelled. If the reservoir is near the belt or power steering pully, the fluid may have gotten on the belt causing it to slip. If this has happened clean the pulleys (engine not running) and clean or replace the belt.

    Let us know what you finally find.
  • edited December 2007
    Well, the noise has gone away by itself, maybe due to the fact that the ambient temperature here in Kansas City is now well above freezing, as the wailing had occurred during the last several much cooler days. Or perhaps fluid that may have gotten onto the belt evaporated, or any air bubbles in the fluid may have dissipated due to driving after lowering the reservoir level.

    Sorry I had initially forgotten to mention that the wailing seemed to be more related to acceleration rather than turning of the steering wheel, althouth it wailed simply idling. I'll let you know if the wailing returns when colder temperatures return, supposedly this coming weekend.

    At any rate thanks for all the great suggestions and assurances.
  • edited December 2007
    over filling any fluid is a no no. you get cavtating or air bubbie,s in pumps and in ten minutes the pump is done never over fill any fluids
    ford are harder to get air out of pumps they though they over fill it and if god was with them the iar would leave the pump and all is well
    some times you need to use a vacuum hand pump with special cap to remove air or lift front of car high on jack and leave seat over night and the iar will raise to top of pump by itself. some ford,s you have to have the wheels off the grounds as you turn the steering whell side to side to help remove the air. they did something wrong. question did your brother in law do this work? if you got the pump from advance auto take it back. if your brother in law did the work make sure he has the proper pully removing tool or you will belt problems. if pully is bent.
  • edited December 2007
    over filling any fluid is a no no.

    Well, it depends on the circumstances. You don't want to seriously overfill your crankcase, because the crankshaft will beat the oil into a useless foam. On the other hand, overfilling your windshield washer fluid won't do any harm. It all depends on whether the intakes and pumps will mix air into the fluid, or cause some other problem. Follow the instructions and try not to go above the "Full" line. At the least, the extra fluid will be expelled and you will have wasted money and made a mess. Also follow instructions to purge air from any system, if needed (coolant, PS, brakes,...).
This discussion has been closed.