just put in a new rack in 2004 mercury grand marquis What fluid do i use some say regular power steering some say mercon 5
Everyone including the dealer has a different opinion
Everyone including the dealer has a different opinion
What P/S Fluid For 2004 Mercury Grand Marquis?
- Thread starter crazyoildude
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Mercon V.
I'd use ATF and sleep well.
crazyoildude, Ford has never spec'd regular power steering fluid, so you can discount those opinions. Your car originally called for plain Mercon in the P/S, but since that has been superceded by Mercon V, that's what you should use. If the dealer is telling you anything different, find another dealer.
i have called the oil companies 5 dealers and a distributor...I heard regular power steering fluid dexron/mercon, mercon 5, valvoline dexron3 hm, the dealer parts guy told me i have to use their "special stuff"
The owners book told me to use mercon atf.
So far i have put in mercon5 but there was some regular power steering fluid put in from my impatient brother that wanted the car off the lift...Also another dealer parts guy we deal with every day said to use a conventional mercon and dont use the mercon5
We rebuild engines all day and dont have this problem..
The owners book told me to use mercon atf.
So far i have put in mercon5 but there was some regular power steering fluid put in from my impatient brother that wanted the car off the lift...Also another dealer parts guy we deal with every day said to use a conventional mercon and dont use the mercon5
We rebuild engines all day and dont have this problem..
dnewton3
Staff member
Let me make this simple.
Use either a (former) Mercon product such as all the DEX/Merc, D3/M, etc products that exist on the market today. Or, use a Mercon V product. Your steering rack will not know the difference.
How would I know?
Because I worked at the Ford/Visteon plant in Indy, from 1990 to 2006, that manufactured all the steering system components. In fact, for a while, I actually supervised the very EN/FN assembly line that manufactured that steering rack system for your car. To this day, all the steering system compontents are still tested with the equivilant of Mercon, even though it's not licensed to the general public. When Ford switched over publically, our massive multi-thousand gallon test systems were never changed over.
Bottom line is that either a (former) Mercon type, or (current) Mercon V, fluid will both work. Do NOT use a typical "power steering" clear hydraulic fluid such as what you see from GM or the aftermarket.
How's that for insider info?
Use either a (former) Mercon product such as all the DEX/Merc, D3/M, etc products that exist on the market today. Or, use a Mercon V product. Your steering rack will not know the difference.
How would I know?
Because I worked at the Ford/Visteon plant in Indy, from 1990 to 2006, that manufactured all the steering system components. In fact, for a while, I actually supervised the very EN/FN assembly line that manufactured that steering rack system for your car. To this day, all the steering system compontents are still tested with the equivilant of Mercon, even though it's not licensed to the general public. When Ford switched over publically, our massive multi-thousand gallon test systems were never changed over.
Bottom line is that either a (former) Mercon type, or (current) Mercon V, fluid will both work. Do NOT use a typical "power steering" clear hydraulic fluid such as what you see from GM or the aftermarket.
How's that for insider info?
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When we had high mileage 4.6L cars with noisy steering pumps, I would use the turkey baster method with mercon V, and that would quiet them up right away.
I suppose the gallon of regular mercon (supertech brand) from walmart would be cheaper, and work the same.
I suppose the gallon of regular mercon (supertech brand) from walmart would be cheaper, and work the same.
dnewton3, that is awesome info!
When Ford dropped plain Mercon, I bought a case just to have for the power steering systems in my Marauders, and in my sister's Taurus and niece's Contour. They have since sold those cars, so my case will last me about forever now.
I do have a question that's been bugging me, and it seems you're the very person to answer it.
Since Ford switched to MV in 1998, why didn't they spec it for the P/S systems as well? It took them until they dropped Mercon in 2007 to say that it's OK to use in steering...
When Ford dropped plain Mercon, I bought a case just to have for the power steering systems in my Marauders, and in my sister's Taurus and niece's Contour. They have since sold those cars, so my case will last me about forever now.
I do have a question that's been bugging me, and it seems you're the very person to answer it.
Since Ford switched to MV in 1998, why didn't they spec it for the P/S systems as well? It took them until they dropped Mercon in 2007 to say that it's OK to use in steering...
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Kestas
Staff member
Now you have me worried. I use the generic ps fluid for everything I own. Yet you say not to use it on Ford ps systems that specify Mercon or Mercon V. Is this because all testing is done only with Mercon, and thus it is unknown whether other fluids are okay, or because there is specific knowledge that other fluids can harm the system?
I looked up the notes on my 01 Sable. I find it interesting that it recommends Mercon V for the transmission, but Mercon for the ps system.
I looked up the notes on my 01 Sable. I find it interesting that it recommends Mercon V for the transmission, but Mercon for the ps system.
Most of the Ford's use Transmission fluid in the power steering units, everything I have owned from the 90's on up has used Transmission fluid.
That clear power steering fluid that you bought isn't the correct fluid, but I doubt it would hurt anything in the pump.
That clear power steering fluid that you bought isn't the correct fluid, but I doubt it would hurt anything in the pump.
Originally Posted By: RF Overlord
Since Ford switched to MV in 1998, why didn't they spec it for the P/S systems as well? It took them until they dropped Mercon in 2007 to say that it's OK to use in steering...
Cost, probably. Why spec MV for power steering when regular Mercon works as well for half the price?
You might say, but Ford doesn't care what their customer pays...true, but what about warranty work? Then Ford is paying. And Ford don't wanna pay for Mercon V when Mercon will do.
Since Ford switched to MV in 1998, why didn't they spec it for the P/S systems as well? It took them until they dropped Mercon in 2007 to say that it's OK to use in steering...
Cost, probably. Why spec MV for power steering when regular Mercon works as well for half the price?
You might say, but Ford doesn't care what their customer pays...true, but what about warranty work? Then Ford is paying. And Ford don't wanna pay for Mercon V when Mercon will do.
i use motul rbf 600 its a dot 4..works great!!
Originally Posted By: boxcartommie22
i use motul rbf 600 its a dot 4..works great!!
Uh, what?
i use motul rbf 600 its a dot 4..works great!!
Uh, what?
That was great info... I have a question for you i just installed a remanufactured rack and pinion in that 2004 mercury grand marquis with about 34,000 miles on it and the left side of the old one had a lot of play...Now im worried that i got rid of a unit with 34,000 miles and maybe it was rebuilt and has 200,000 miles what usually goes bad on them im worried that my 80 year old mother will lose steering one day
thanks for the info
thanks for the info
dnewton3
Staff member
I cannot comment on the "clear" p/s fluid and how it might react with the ATF and/or the seals. That is why I (pardon the pun) steer people away from mixing the two. I'm not saying it's bad; I just don't know that it's OK. What may not be bad now, may react horribly over the long term. It's an unknown that I cannot fairly comment on; I'm not a chemist. My advice is to not do it. Just because it "can" be done, doesn't mean it "should" be done.
I don't see the reason to risk any potential unfortunate result when there are (seemingly) a bazillion gallons of D3/M, Dex/Merc, etc on the aftermarket, or you can upgrade to a Mercon V product. Those are easily attained, reasonably priced, and correctly spec'd.
I don't see the reason to risk any potential unfortunate result when there are (seemingly) a bazillion gallons of D3/M, Dex/Merc, etc on the aftermarket, or you can upgrade to a Mercon V product. Those are easily attained, reasonably priced, and correctly spec'd.
Kestas
Staff member
That makes sense. I work with seal engineers. Their seals goes into engines, transmissions, differentials and ps systems for the OEM market. I asked them if there is a compatibility problem in using synthetic fluid with our seal material, and whether they test for it.
They told me they test only with the manufacturer specified fluid. They can't afford to test all the contingencies their seal may experience. Yet here on BITOG we use all kinds of alternate synthetic fluids in our applications with no problems.
They told me they test only with the manufacturer specified fluid. They can't afford to test all the contingencies their seal may experience. Yet here on BITOG we use all kinds of alternate synthetic fluids in our applications with no problems.
dnewton3
Staff member
You are correct.
The "world of possibilities" is nearly endless nowdays. OEMs, and their suppliers, have their hands full just testing the known conditions, let alone the "what if" scenarios.
Again, not that you did something wrong. I just cannot assure you it will end well. It probably will, but that is different than stating is definitely will.
But I do know that licensed/spec'd products will always perform to a satisfactory minimum, and that using those products in conjunction with following the OEM maintenance plan, will typically take any piece of equipment far past the point that most would own it.
The "world of possibilities" is nearly endless nowdays. OEMs, and their suppliers, have their hands full just testing the known conditions, let alone the "what if" scenarios.
Again, not that you did something wrong. I just cannot assure you it will end well. It probably will, but that is different than stating is definitely will.
But I do know that licensed/spec'd products will always perform to a satisfactory minimum, and that using those products in conjunction with following the OEM maintenance plan, will typically take any piece of equipment far past the point that most would own it.
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Kestas
Staff member
I'm actually not too worried after your additional information. I, as others, am always second-guessing the manufacturers recommendation.
I often think they specify ATF to simplify fluid management for their dealers, and that ps systems aren't as demanding of the fluid as automatic transmissions are. Heck, Volvo specifies nothing more specific than "ATF" for ps systems.
There's also the commonly accepted thought that, for older cars, the present ATF formulations have additives designed for transmissions that did not exist when the car was made, and these additives may be too tough on old ps systems. Generic ps fluid doesn't have these additives.
I often think they specify ATF to simplify fluid management for their dealers, and that ps systems aren't as demanding of the fluid as automatic transmissions are. Heck, Volvo specifies nothing more specific than "ATF" for ps systems.
There's also the commonly accepted thought that, for older cars, the present ATF formulations have additives designed for transmissions that did not exist when the car was made, and these additives may be too tough on old ps systems. Generic ps fluid doesn't have these additives.
dnewton3
Staff member
Agreed.
The p/s system is, after all, a simple hydraulic pump and cylinder concept, and nothing more.
They could possibly use just about any hydrualic fluid (engine oil, tranny oil, p/s fluid, etc) and make it work, but most OEMs spec fluids that meet two specific criteria:
1) they perform to some spec'd minimum standard
2) they cost the least in doing so
The p/s system is, after all, a simple hydraulic pump and cylinder concept, and nothing more.
They could possibly use just about any hydrualic fluid (engine oil, tranny oil, p/s fluid, etc) and make it work, but most OEMs spec fluids that meet two specific criteria:
1) they perform to some spec'd minimum standard
2) they cost the least in doing so
It always puzzled me as to why Ford used the more advanced ATF fluids in their auto trannies and used "older" fluids in their PS's. I guess the cost of a few cents over millions of units mattered.
In my 1996 Contour Type F ATF is spec'd in the PS, Mercon is for the auto tranny. 15 years later I'm still using Type F ATF. The factory fluid was changed at 9 years, it still looked good. I did multiple turkey baster changes with SuperTech Type F. So far all is ok.
My 2002 F-150 spec'd Mercon V in the auto tranny and Mercon in the PS. After 6 years it looked "yucky" and darkened the PS fluid reservoir badly. I did multiple turkey baster changes with Valvoline and then Mobil 1 Mercon fluid. No change in steering feeel and it made whining noises in the winter. It's quiet now in the warmer weather. I'll see what happens this comming winter.
Whimsey
In my 1996 Contour Type F ATF is spec'd in the PS, Mercon is for the auto tranny. 15 years later I'm still using Type F ATF. The factory fluid was changed at 9 years, it still looked good. I did multiple turkey baster changes with SuperTech Type F. So far all is ok.
My 2002 F-150 spec'd Mercon V in the auto tranny and Mercon in the PS. After 6 years it looked "yucky" and darkened the PS fluid reservoir badly. I did multiple turkey baster changes with Valvoline and then Mobil 1 Mercon fluid. No change in steering feeel and it made whining noises in the winter. It's quiet now in the warmer weather. I'll see what happens this comming winter.
Whimsey
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