Man Reasoning: Outflanked Yet Again

My beloved convertible is getting up there in years.  It's a 2000, but it's still in great shape so Jeff and I decided that we'd wait a year or so to replace it (until we hopefully have enough money in the "car fund" to pay cash for a new(er) car).  When we agreed on this plan, I made sure to note that if things started to go wrong with my car we would need to move up the schedule.  Enter things going wrong with my car.

Last week the "check engine" light came on, and we subsequently found out the in addition to a new radiator, there are a couple of other problems that need to be addressed.  Which I interpret as "put a band aid on that bitch and trade her in ASAP".

Jeff, on the other hand, thinks we should spend the money to fix it and keep it running for another year.  I hate this plan already.  Unfortunately, early in our marriage we agreed that all major purchases require "buy in" from both parties (and frankly, I don't want to open the door on "every man for himself" purchases at this point).  Results could be unpredictable.  So I'm going to have to convince him that it's a good idea to invest in a new car.  Best idea ever!

Here's just a small sample of our recent negotiations.  I don't know how I lost this one, but clearly my negotiation skills could use a little polishing.

LAB:  I think we should replace the Toyota.
Jeff:   I agree.  Next year.
LAB:  I meant now.
Jeff:  I'm aware of that.
LAB:  Why can't we?
Jeff:  Repeat after me:  No. Car. Payments.
LAB:  Can't we use what's in the car fund and cash out some investments to make up the difference?
Jeff:  Did you just say that out loud?  No.
LAB:  Why not?
Jeff:  Investments are for retirement.
LAB:  And major purchases.
Jeff:  Major purchases when we're retired.
LAB:  Let me take you back to February, when we cashed out some investments to buy you a new car.
Jeff:  That was different.
LAB:  Because?
Jeff:  I needed a new car.
LAB:  Exactly!
Jeff:  You don't need a new car.
LAB:  So it's OK to spend money on a new car for you, but not for me.
Jeff:  I needed a new car so we could give my old car to my son.
LAB:  So it's OK to spend money on a new car for you so you can hand down your old car, but not for me.
Jeff:  Exactly.
LAB:  So everyone in the family, including a 15-year-old kid with only a learner's permit, gets newer, nicer cars than I have.
Jeff:  That's just how it worked out.
LAB:  That sucks.
Jeff:  Oh, please.  You drive 18 miles round trip to work.  You're keeping the old car for another year.  At least.  Besides, you love your car.
LAB:  I'd love a new car more.
Jeff:  Don't you mean you'd love a new car more next year?
LAB:  Might I point out that you've bought five freaking cars since we bought my car?
Jeff:   You can try.
LAB:  *swears under breath*
Jeff:  "Project" cars don't count.
LAB:  Five cars.
Jeff:  It's not my fault you agreed to buying them.
LAB:  WHAT?!?!?!
Jeff:  What?
LAB:  I swear to God I want to smack you so hard right now that you'll have three tongues in your shoes.  This conversation isn't over.
Jeff:  We can have this conversation as many times as you want.  Until next year.

This?  Will not stand.  I'm not sure how I'm going to go about it, but I'm getting a new(er) car.  Time to bring out the big guns, people.  If I can find them.