New for me (1999) 4.0 SOHC. What oil? Synthetic?

[MatteoLC]

i JUST bought a 1999 XLT, and it's got 135K miles on it.
I don't know anything about it's history, unfortunately - but got a decent deal, so I thought I'd chance it...

1 - Is it too late to switch to synthetic oil? If I switch, what's the best kind to avoid some of these 'rattling' issues I have read about?
2 - Does the oil filter make any difference?
3 - What should I do for the trans? It seems ok, but I'm not sure how to tell if it needs attention or not.
4 - Is there anything else I should address before driving it?

Thanks for the advice!

 

[Fifty150]

You will be fine switching to synthetic oil. I switched mine at about 200,000 miles. 200,000 miles of the previous owner using the wrong grade of oil with a Fram filter. The synthetic oil additive pack has pretty good detergents. I actually think that the car is running better with each oil change.

I've used Lucas Oil, Royal Purple, Red Line, Mobil 1, and Motorcraft without issue. I have also used 5W20, 5W30, and now, 0W30 without issue. I usually buy cases of Royal Purple from americantrucks.com or americanmuscle.com when they send out those coupon codes in my email, or when amazon.com lowers their prices. I recently bought a bunch of O'Reilly's full synthetic & Pennzoil Ultra full synthetic on sale. The Pennzoil was only $19.16 for 6 quarts at amazon.com. I haven't jumped to the dark side of The Force, or drank the Kool-Aid yet, so I can't comment on Amsoil; although people who use it swear by it.

There are a lot of filter options. Most of my friends like K&N because of the nut on the end. I tend to use Motorcraft, K&N, Mobil 1, & AFE. AFE filters have an attachment for a ratchet handle. If there is one thing that I hate, it's having oil filters at weird angles and in tight spaces, then having to come up with the right filter wrench. K&N's 1" nut, and the AFE's 3/8" drive have solved that problem. When Wally World carried Mobil 1 filters, I used to get them with my 5 quart jugs of Mobil 1 oil. But I also like being able to buy Motorcraft at my local auto parts distributor. You can really save money if you buy auto parts from the distributor instead of the parts counter at the dealership.

 

[MatteoLC]

Awesome... Thanks for the info!!