# 2004 Mercury Grand Marquis - should I switch oil? **URL:** \ **Category:** Maintenance/Repairs\ **Tags:** mercury, grandmarquis\ **Created:** [December 9, 2019, 6:38am UTC](https://community.cartalk.com/t/2004-mercury-grand-marquis-should-i-switch-oil/154305 "2019-12-09T06:38:14Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![Ray12](https://avatars.discourse-cdn.com/v4/letter/r/a9a28c/32.png) [@Ray12](https://community.cartalk.com/u/Ray12)\ **Post date:** [December 9, 2019, 6:38am UTC](https://community.cartalk.com/t/2004-mercury-grand-marquis-should-i-switch-oil/154305/1 "2019-12-09T06:38:15Z")
Car uses oil no smoking or leaks. Adding one quart a month. I use 5w20 Castries. Should I go to 5w30 and add lucust oil treatment or what do you recommend ---
**Author:** ![oldtimer-11](https://avatars.discourse-cdn.com/v4/letter/o/e79b87/32.png) [@oldtimer-11](https://community.cartalk.com/u/oldtimer-11)\ **Post date:** [December 9, 2019, 7:01am UTC](https://community.cartalk.com/t/2004-mercury-grand-marquis-should-i-switch-oil/154305/2 "2019-12-09T07:01:56Z")
That sort of depends on hpw many miles you drive a month. ---
**Author:** ![Purebred](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/purebred/32/46796_2.png) [@Purebred](https://community.cartalk.com/u/Purebred)\ **Post date:** [December 9, 2019, 10:50am UTC](https://community.cartalk.com/t/2004-mercury-grand-marquis-should-i-switch-oil/154305/3 "2019-12-09T10:50:37Z")
Oil usage is measured in miles. How many miles before added oil and how much do you add? ---
**Author:** ![VOLVO-V70](https://avatars.discourse-cdn.com/v4/letter/v/8e8cbc/32.png) [@VOLVO-V70](https://community.cartalk.com/u/VOLVO-V70)\ **Post date:** [December 9, 2019, 2:03pm UTC](https://community.cartalk.com/t/2004-mercury-grand-marquis-should-i-switch-oil/154305/4 "2019-12-09T14:03:46Z")
Ray , it is a little difficult to give you an answer from your vague post. Do you only check the oil level once a month ? How many miles do you drive before you add a quart ? What does you manual call for oil ? How many miles on your 15 year old vehicle ? ---
**Author:** ![Docnick](https://avatars.discourse-cdn.com/v4/letter/d/ecae2f/32.png) [@Docnick](https://community.cartalk.com/u/Docnick)\ **Post date:** [December 9, 2019, 3:00pm UTC](https://community.cartalk.com/t/2004-mercury-grand-marquis-should-i-switch-oil/154305/5 "2019-12-09T15:00:04Z")
Look in the owner’s manual and see what it says. This car has been on the market for many years and originally had a 5w30 specified. To squeeze a few extra miles per gallon, Ford changed the spec to 5W20 on may of their cars, with resultant oil use problems since 5W20 is extremely thin and needs a very tight engine. I would have no problem switching to a high quality 5W30 oil with this vehicle. Try it an see if it makes a difference. I f you have a leak somewhere or bad valve guide seals the switch won’t help you. ---
**Author:** ![Tester](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/tester/32/15976_2.png) [@Tester](https://community.cartalk.com/u/Tester)\ **Post date:** [December 9, 2019, 5:47pm UTC](https://community.cartalk.com/t/2004-mercury-grand-marquis-should-i-switch-oil/154305/6 "2019-12-09T17:47:47Z")
If the engine uses oil, and there are no leaks, then the oil is being burned, Add a can of this to the oil, and see if the oil consumption slows down or stops. [https://www.restoreusa.com/index.php](https://www.restoreusa.com/index.php) Tester