So I recently purchased a fairly modified xj. I've noticed when I get up to higher speeds my windshield gets slightly foggy in one spot right in the middle . I'm wondering if this common or not. Also when I first begin driving occasionally there's some fog that comes out of the ac vents that's odorless but odd. Any help welcome thank you

 

Good question i had the same thing happen a few years back. Your heater core is dying. The good news is that you've caught it fairly early on so it won't be a complete mess to fix (if you decide to do it yourself). The bad news is that in order to replace the heater core you need to remove the dash - and yes it's a very involved and tedious job..... I had a mechanic do it and it was expensive so be prepared for that..... I waited about 5-6 months to get it fixed before the fog became too ridiculous. Good luck!!!!

 

I agree on the heater core.
Never done one but hear it is not a hard job but tedious and time consuming.
10 hours seems to be the norm.
Guys report that after doing one the first time they knock it out in 5 or 6 hours if and when they have to do another one. LOL.
Plenty of write ups. You don't mention what year your Jeep is. The procedure will vary depending on the year.
Always good to give that info whenever asking a question.

 

its a 2000 cherokee sport

 

It is time consuming. If you block out a weekend of time lock the garage door crank up your favorite tunes and enjoy the process it can be therapeutic. First one takes t he longest. They go a little quicker every time after that..