Marriage .. 1998 Mercury Mountianeer ... 2000 Mercury Mountianeer

[Idaho_Dave]

I was watching one of the local sales sites this week and found a 1998 Mercury Mountaineer with a subtle knock in the engine. I already have 2000 Mercury Mountaineer with a good engine with 157000 miles on it. My first line of thinking was I would buy the 1998 and use all the parts to fix the damage that my 4 children have done to the 2000 (fender, Paint peeling, broken headlights, flat tires, etc ..) Once I got it home and cleaned up I realized that the 1998 is in much better shape and I am considering either getting a short block and moving the top end components over, or pulling the engine out of the 2000 and putting it in the 1998, or pulling the 2000 and rebuilding it and then putting it in the 1998. Both have the 5.0 engine. This is my sons' car and I intend to have him just drive the 1998 until the engine blows, or we have time to fix it. I want to start buying parts now so that I am ready to get it fixed in the next few months.

Now that we have covered the backstory, let us cover my hopes for this build. The 2000 has had nothing but issues over the last few years. One sensor after another has gone out and it has essentially run with the check engine light the last 5 years no matter what I tried. It has 157K on the engine so it is no spring chicken. I am hesitant to move into the 1998 because I have had such bad luck with it. (I know that is not logical, but I still am anxious about it), My overall goal would be making the engine as reliable as possible while keeping the budget in mind. I would like to fix any future know problems as I am rebuilding to increase reliability.

SO my options are
Switch the 2000 motor to the 1998 as is ...
Buy a short block and move the 1998 heads and intake over to to the new block ...
pull the 2000 motor and rebuild it .... then put it in the 1998.

I have never rebuilt a motor and I am a little intimidated to try, but I understand the engines enough that I am confident I could pull it off (especially the top end). The short block option sounds like the most reliable to me. I am open to all opinions and even options that I haven't thought of yet. I really want to hear anybody's opinion on this. Thanks

 

[410Fortune]

Where are you in Idaho?

 

[974X4BLACKSPORT]

I now pronounce you "Mercury and Mercury"!

 

[Idaho_Dave]

Where are you in Idaho?

I am from Rigby ....

 

[Redmanss]

I'd start with giving the '98 a good tune-up and getting good fuel into it to chase down the knock problem before thinking engine swap, essentially prove it's a rod knock you're dealing with and not just a detonation knock.

In higher altitude Idaho, you probably have a lot of 85 octane with 10% ethanol that's also the cheapest gas and what many run in vehicles they don't care about, so run/drain the tank to empty and get some good top tier brand 87+ pure gasoline in there along with some cleaner, run and repeat a couple tanks. Check the plugs and change as necessary, can't recommend the Autolite Iridiums more (although I'm on a 4.0 OHV currently but recommendation still applies), and swap out the fuel filter for a new one. All of that can be swapped onto the new block if it is a rod issue at zero additional cost to you if that is the case, but can certainly save you some money if it's not as serious as you suspect.

 

[Idaho_Dave]

Thanks, Red! I am in the process of trying the cleaner (seafoam in the tank) and higher octane fuel route (no improvement so far). The truck came out of Utah (where the gas is a little better), but the elevation is about 5500ft.Cleaner suggestions? I have had two mechanics confirm the diagnosis, but I (like you ) am skeptical. Are you solid on the autolites? I have been told these engines can be picky about the plugs and I want to be sure that a 5.0 isn't going to pitch a fit if I switch em out. ( I have CEL paranoia from trying to fix the 2000 debacle). I have to pull the engine on the 2000 in the next few weeks either way because the wife says I am only allowed to have three projects parked out front at any given time ( I have about 6) and this one will push her over the edge.

 

[Redmanss]

I'm solid on the Autolites in my 4.0 OHV and it helped me regain 10% fuel mileage from the old stock plugs that had 125k on them, there's a few here on the board who used them in their 5.0 as well and had good things to say. Check RockAuto, with rebate they were under a dollar each recently, not sure if that deal is still going.

Utah fuel is mostly 85 octane plus ethanol for its base grade, I'm originally from there and that's what's most common at all the stations for the cheapest gasoline. For cleaner, I mostly recommend just using only top tier fuel from the good name brand stations with quality full syn oil and that keeps the buildup from happening in the first place, but Sea Foam, Lucas, Gumout, or Amsoil will each give a good boost to the cleaning. Anything is better than nothing and will at least start cleaning up the top half of the engine for later if you do the short block swap.

 

[RandomNerd2000]

I personally only use Autolites in Fords, only bad experience I've ever had was I had one rusted round in my 2000 V8 when I got it, I did get it out without removing the head on a 250K+ motor though. Otherwise it's been smooth sailing, although don't put Autolites in the lawn mower, or generator, I've found they don't do well there.

 

[Mbrooks420]

After trying others I will only run platinum Motorcraft plugs in my 5.0.