# Heater Core Replacement 1994 Grand Marquis **URL:** \ **Category:** Maintenance/Repairs\ **Created:** [November 24, 2015, 11:49pm UTC](https://community.cartalk.com/t/heater-core-replacement-1994-grand-marquis/91804 "2015-11-24T23:49:21Z")\ **Posts on this page:** 12\ **Page:** 1
**Author:** ![GrandMarquis](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/grandmarquis/32/15596_2.png) [@GrandMarquis](https://community.cartalk.com/u/GrandMarquis)\ **Post date:** [November 24, 2015, 11:49pm UTC](https://community.cartalk.com/t/heater-core-replacement-1994-grand-marquis/91804/1 "2015-11-24T23:49:21Z")
[Crownvic.net](http://Crownvic.net) insists that a heater core replacement does not require evacuation and recharge of the air conditioner. “You don’t need to touch the A/C at all” was posted for a 1999 Crown Victoria Police Interceptor. I haven’t yet found information specifically for a 1994 Grand Marquis LS. My mechanic insists that he has to service the Air Conditioning. Tells me he’s a “French Model”. What should I do? ---
**Author:** ![FoDaddy](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/fodaddy/32/717_2.png) [@FoDaddy](https://community.cartalk.com/u/FoDaddy)\ **Post date:** [November 25, 2015, 12:41am UTC](https://community.cartalk.com/t/heater-core-replacement-1994-grand-marquis/91804/2 "2015-11-25T00:41:43Z")
I’m fairly certain a heater core replacement wouldn’t necessitate the evacuation and recharging of the A/C system. I’d ask another mechanic. ---
**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:** [November 25, 2015, 12:58am UTC](https://community.cartalk.com/t/heater-core-replacement-1994-grand-marquis/91804/3 "2015-11-25T00:58:48Z")
The heater core is contained in a separate plenum of that of the AC evaporator. So the heater core can be replaced without disturbing the AC system. Tester ---
**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:** [November 25, 2015, 1:41am UTC](https://community.cartalk.com/t/heater-core-replacement-1994-grand-marquis/91804/4 "2015-11-25T01:41:47Z")
Tells me he is a " French Model " What does that mean? ---
**Author:** ![GrandMarquis](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/grandmarquis/32/15596_2.png) [@GrandMarquis](https://community.cartalk.com/u/GrandMarquis)\ **Post date:** [November 25, 2015, 5:13am UTC](https://community.cartalk.com/t/heater-core-replacement-1994-grand-marquis/91804/5 "2015-11-25T05:13:23Z")
My mechanic is referring to a State Farm TV commercial about not trusting things you read on the internet when he tells me he’s a French model. ---
**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:** [November 25, 2015, 6:53am UTC](https://community.cartalk.com/t/heater-core-replacement-1994-grand-marquis/91804/6 "2015-11-25T06:53:25Z")
When Tester gives you an answer, I would trust it. ---
**Author:** ![the\_same\_mountainbike](https://avatars.discourse-cdn.com/v4/letter/t/c89c15/32.png) [@the\_same\_mountainbike](https://community.cartalk.com/u/the_same_mountainbike)\ **Post date:** [November 25, 2015, 8:08am UTC](https://community.cartalk.com/t/heater-core-replacement-1994-grand-marquis/91804/7 "2015-11-25T08:08:39Z")
My first inclination is to say you need a new mechanic, but upon thinking about it I realized that accessing the heater core in this car MIGHT require removing some AC components, which would necessitate servicing the system after. I trust Tester’s expertise, but you might want to invest in a repair manual for this car to verify your mechanic’s statement… or discover that you need a new mechanic. We’ve all read about cars that require jacking up the motor to change the rear sparkplugs, and I had a truck that required removing the front bumper to change a headlight bulb. Perhaps on your car some AC components are in the way of the heater core. ---
**Author:** ![GrandMarquis](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/grandmarquis/32/15596_2.png) [@GrandMarquis](https://community.cartalk.com/u/GrandMarquis)\ **Post date:** [December 13, 2015, 1:23am UTC](https://community.cartalk.com/t/heater-core-replacement-1994-grand-marquis/91804/8 "2015-12-13T01:23:59Z")
I checked with the local Lincoln-Mercury dealer. He says that their instructions call for an evac and recharge of the A/C with the heater core replacement, but if they do the job they will check and my car may not need it. My mechanic says that the Ford instructions he has call for the evac and recharge. Is their a special reason that Ford calls for this additional procedure to replace the heater core? I’m a little confused since my Air Conditioning works fine even after bypassing the heater core. ---
**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 13, 2015, 1:33am UTC](https://community.cartalk.com/t/heater-core-replacement-1994-grand-marquis/91804/9 "2015-12-13T01:33:36Z")
Bypassed heater core means you have no heat and I guess that means you are going to park this vehicle until spring . Otherwise just get it fixed. ---
**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 13, 2015, 1:46am UTC](https://community.cartalk.com/t/heater-core-replacement-1994-grand-marquis/91804/10 "2015-12-13T01:46:01Z")
Here’s the instructions for replacing the heater core in your vehicle. > **[How do i replace the heater core on a 1994 mecury grand marquis ls](https://www.justanswer.com/mercury/2z10n-replace-heater-core-1994-mecury-grand-marquis.html)** > > How do i replace the heater core on a 1994 mecury grand marquis ls - Answered by a verified Mercury Mechanic Nowhere does it mention having to mess the AC system. Tester ---
**Author:** ![GrandMarquis](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/grandmarquis/32/15596_2.png) [@GrandMarquis](https://community.cartalk.com/u/GrandMarquis)\ **Post date:** [December 14, 2015, 9:33am UTC](https://community.cartalk.com/t/heater-core-replacement-1994-grand-marquis/91804/11 "2015-12-14T09:33:47Z")
Why does Ford indicate to my mechanic that he needs to service the A/C? ---
**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 14, 2015, 10:38am UTC](https://community.cartalk.com/t/heater-core-replacement-1994-grand-marquis/91804/12 "2015-12-14T10:38:00Z")
Let me put this straight forward. Ford or no other service manual indicates that the AC needs to be disturb when replacing the heater core in your vehicle. The only conclusion I can come up with is, these so called mechanics are trying to pad the bill by including an AC service that isn’t required. Tester