1994 needs some help

[Savage22]

Ive got a 1994 explorer with real close to 250,000 miles on it.
I have always had an issue at random with idle. usually it is during colder weather. You start it up and it will roughly idle, ill do the best to describe it...
every few revolutions it sounds like it just revs 200 rpm higher then back to normal. sometimes it goes 200 lower (maybe more) and you think it will die. Kinda sounds like an agressive cam almost.
after you warm it up and drive it seems fine but sometimes at a red light it will just act likes its trying to go forward with a terrible idle. I think the torque convert is getting stuck. Does that sound correct?
My other issue is EVERYTHING leaks. transmission, oil, coolant. Luckily they are NOT mixing together and they are not burning (no smoke.) the coolant seems to be the smallest leak and dont normally have to add much very often. the oil on the other hand isnt that great. I would have to say its leaking from multiple areas, oil pan and valve cover im sure. Where else could it be coming from?
how hard are these gaskets to replace? I am currently taking automotive classes at college so i have access to a full shop but this truck is also my daily driver.
Im tempted to try some "stop-leak" type stuff especially for the oil but would be worried about it stopping up other parts. I also seem to have just recently gained a "tick" in the engine bay that changes with RPM, after reading another post with exact same symptoms it seems to be a rocker doing it. I believe this started after a recent oil change. what oil would you guys suggest i run with these symptoms?
thanks for any advice.

 

[Anime]

Welcome to the forums!


It only has a rough idle, but the check engine light has never come on? If you've had any CEL's at all, you should use an OBD I tester (since you probably have access to it in class) and hook it up to pull the codes and find out where the problem is.

Otherwise, you should probably start with basic maintenance items. Old dirty spark plugs (or sometimes poor quality plugs), can cause idle issues. Using the OEM Motorcraft Platinum Plus/Double Platinum plugs helps performance and idle. Worn on plug wires can also cause issues. Replace with either a good quality BOSCH set or perhaps even OEM Motorcraft if you don't want to spend extra money on a performance set.

If you've read the forums, you'll know that the Mass Airflow Sensor on these can be cleaned quite easily, and usually makes a difference in performance and idle.

You should also check the vacuum tree on the rear drivers side of the engine for loose or leaking vacuum caps, which can also cause issues.


As for the leaks, the coolant might be coming from a loose water pump if it's leaking down the front of the oil pan, or you might just have a loose coolant hose clamp. There's coolant hoses going to and from the heater core, and the top and bottom radiator hoses as well. Oil leaks from the oil pan gasket, valve cover gaskets, and sometimes even the head gaskets are pretty common with age. Sometimes the heads will crack, which would be a source of both oil and coolant leaks.


You can attempt a cheap "fix" by using high-mileage oil, since it contains the same gasket-expanding additives as the "stop-leak" stuff without causing problems like adding the thick oil treatments will.


Since you're taking automotive classes, and have access to the shop and tools, if your Explorer is in good shape and you plan on keeping it, or think it would be a good idea to do some work on it so you can sell it for a decent price down the road, you should consider doing some work like replacing the lifters, which is a common issue on Explorers, and also lets you replace the valve cover gaskets. You might also consider replacing the coolant/heater system hoses rather than just sticking some stop-leak in there, since coolant needs to be changed every so often anyway, and replacing the hoses while the system is drained makes sense.

You'll be saving yourself a ton of money doing the work yourself, learning a lot about the basics of automotive maintenance in the process, and maybe even have some help from the instructor and other students along the way, making for easy work.

I say fix EVERYTHING while you have access to a full shop. Your vehicle is a prime candidate for the same kind of diagnosis and repair work a shop tech sees everyday.
If you plan on working in the field, most customers aren't going to be pleased with a "stop-leak" fix as a professional repair.

 

[Savage22]

I agree with ya. id like to fix most but doubt i could sell it for anything down the road. 250,000 1994 and you've lost them lol. Its all 100% stock im sure. my dad owned it, pull all the miles on it and never maintained anything. It still has the floor mats i bought for it a decade ago.
Ive already found the vacuum leaks and resolved them with proper hoses. whoever he had fix them the first time put the wrong type on so they just would collapse over time under throttle.
The problem with replacing alot of it is that i wont have a vehicle to drive while working on this one. lol
the 4wd doesnt work either, and im 100% sure its the crap auto hubs. I plan on converting them to manual...
It definetely needs a tune up and i was just looking at spark plugs for it the other day.
the airbox is also busted... It doesnt really work. I just need this to last me a few more years and ill retire it or really overhaul it.
also the AC doesnt work it, one of the lines rusted out and busted. lol
it drives good and i get 150 miles till 1/4 of a tank.