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1989 Town Car Questions

Thanks for your consideration as usual. You are super.

I detect air coming from what I believe to be underneath the windshield as it meets the dash right about in the middle of the driver’s side defroster vent. My mechanic says this is air coming from the defroster as the blend door is leaking. But I don’t think so: The air comes in even when the HVAC system is off; the amount of air coming in increases with vehicle speed; the HVAC system works perfectly; the air from the defroster when it is on is the same temp as the other side where there is no leaking. I suspect that the windshield seal (urethane?) at this spot is somehow decayed, allowing air to come into the cabin underneath the windshield. Who is correct? And if it that be me, what’s the easiest way to correct this? Accessing the bottom of the windshield glass through the engine bay looks very hard. If I took off the dash cap, would that allow me to address the issue by applying (squirting?) some urethane into the problem area?

The oil dipstick (which I assume to be original) on this engine is confusing. When I change the oil, 5 quarts, the reading is way above the narrow crosshatched area. So I never know when it is 1 quart down… that at the bottom of the crosshatched area or above that?

Should I use an oil formulated for older engines? My engine, original to the car, has 75K on it. I get about 1500-2000 miles to a quart, depending on how how much I have driven at highway speeds. The engine does not smoke or leak (see below). I use 5W-30 oil.

My mechanic says the oil pan has two drain plugs. The front one is seeping a bit, which he says is not a big deal and can be fixed. But why are there two drain plugs?

Many thanks Bill! I am obsessed with this beast.


Hi Peter –

Some of these cold air leaks can be difficult to locate. The best way to diagnose this type of leak is to use an assistant to ride with you with the glove box removed in order to correctly pinpoint the leak. The proper maintenance manual should also be used to carefully test for correct operation of the various shut off doors in the duct system. One popular area to check is the right side recirculate air door assembly operation. If you do not have the correct FoMoCo shop manuals, we can make arrangements to send you this section of the manual.

The oil pan has two drain plugs because there are two oil sumps in this style. Both plugs along with the oil filter need to be removed in order to drain the entire system. The oil level will then read full ( if the dipstick is the correct one ) when the engine is started and then shut off with the five quarts of oil and a new oil filter installed. We would advise for you to continue using the same 5W30 oil.

We wish you the best of luck with your cold air leak.




Dear Bill:

Thank you for your reply below, and apologies for the delay in response.

You do a GREAT service to all us Lincoln nuts and I can’t thank you enough!

I have read your response carefully and am afraid that I must ask for a clarification. 

The cold air leak I spoke of is on the drivers’ side, right behind the defroster vent, next to the windshield.

For the life of me, I can’t figure out why you suggest that I to use an assistant to ride with (me) with the glove box removed in order to correctly pinpoint the leak.

The glove box being all the way over on the other side of the dash board.

You also suggest that I check the right side recirculate air door assembly operation.  Did you not mean to say “left side?”

Again, my thanks for your assistance and sorry to bother you again!




Hi Peter –

The reason for the assistant suggestion is that while you drive, he would be able to reach under the dash somewhat through the glove box door to find out by feel if there are any incorrect amounts of air movement under the dash. The ductwork under the dash can also be checked to see if there are possibly any parts missing or not installed correctly. Of course, the ductwork doors must be also be installed properly and operating as they were designed, We have not experienced this type of leak as you describe and do not know if any repairs were performed on these areas and therefore, we would need to inspect those areas up close to be accurate. If you believe that the leak is originating at the windshield area where it meets the cowl area, that area of glass installation along with the outside cowl air inlets should be inspected by a good automotive glass or body shop.

The recirc unit that I am referring to is located at the right side (passenger side) kick-pad area. On airconditioned vehicles this assembly is part of the air handling.

The Factory Shop Manual has very good diagrams which should assist you, if you don’t have one – it’s the best money you will ever spend on the car. We have them on hand here at Lincoln.





Thanks Bill!


I have the shop manual and will consult it.


Does your shop do work on Lincolns like mine?  Maybe I will need to visit someday…..?







Hello Peter –

It was nice to receive your responses regarding Bill’s Corner. Yes, we perform plenty of repairs and customer maintenance to Lincolns such as yours as well as the newer ones. We also have an increasing stock of the more difficult to find parts on hand that are in good used condition as well as some new items.

If you plan to pay us a visit, please give us a heads up by calling and letting Chris or John know so that when you are here, we will be able to give you a short tour of the many collectible Lincolns that we are presently tending to.




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