So the original motor was making some pretty awful sounds, I figure it would be more work fixing the original than to find another engine. So I got that pulled and was being cheep and got an engine for $250, I got it all put back together to find out it was just as bad as the original if not worse! Eventually I found an engine with 70k on it for $500. The installation went smoothly, we'll had a tough time getting the engine to line up with the train and motor mounts. But after my relentless attempts to get my truck on the road, I was sure this one would do the trick.
It was time to fire it up, after replacing the engine twice, I was just about sick of that truck. It started right up and sounded great, no knocks from the push rods, no knocks from the bottom end, every thing seemed to be in good working order.
Untill i checked the oil the next morning. i had just put about 40miles on it the night before to work the kinks out, and do some adjustments. Come to find out it was 2 quarts low on oil!! Freaked me out! I could see oil coming out where the trani bolts up to the engine. And my first thought was the rear main seal... Am I wrong?? The guy I got the engine from said it had been sitting for a while and that the truck caught fire, and was totaled. What else would allow it to leak that much oil in such a short time??? It's not the oil filter it's not the pan gasket, it came from the back of the engine and out the drain hole between the trani and engine.

I am about to buy a gasket rebuild kit, pull the engine and put it on the stand, and replace the gaskets, I don't want to take this truck apart again, I don't know how bad the fire was bit the only thing burnt on the engine was the oil cap.

I was just looking for some outsiders suggestion on what the oil leakage might be, if i could have forgot to do something while completing the installation, let me know your thoughts, and what you would do.

94 Mazda b4000 4x4 4.0L 5 speed

 

I will be purchasing the gasket set and the rear main seal on Friday the 19th,what other things should I get to make this a smooth and durable repair??

 

you say gasket set! which one does it have a pan gasket, valley gasket valve cover? If the engine is out R&R all 3, plus while there look at front timing seal. Supposedly a special tool is needed to put the rear main in, I didnt, I just did it the old fashioned way and it was good. Thought I had a rear main out and it turned out to be the gasket from the valley/intake that was leaking and running down to look like a rear main leak! They also replaced the valve cover gaskets and the pan had a slight leak. I have a small indy shop do my work now, I am getting too old and slow to be crawling around under the trucks any more, plus they can do in 2 days what takes me a week part time!

 

I doubt that a rear main seal could leak that volume of oil that quickly. The rear main seal is well above the level of the oil in the pan, and is not under pressure unless the PCV system is compromised allowing blow by to put pressure on the crankcase.

I once bought a truck, ran it for years, pulled the engine to replace the crank bearings, and found it had never had a rear main seal. Guess that explained why the clutch was always grabby.

 

I didn't think it would leak that much either, something is obviously wrong. No it hasnt been pulled back out yet, i was planing on doing it these next couple though. i am getting the head gasket kit and the lower/ conversion gasket set. Now what is the valley gasket??? Isn't that where the intake sits pretty much??

I was looking at stuff from orielys and their gaskets didn't seem to be of that great of quality, yes they are cheep but I don't think I want to go that way. I checked out autozone an they have a more performance and higher quality gasket sets. The head gasket set comes with new head bolts and the lower gasket set comes with the rear main seal so that's good and it says the gaskets are OEM standard. They also have a rear main seal remover/ installer for 4 bucks, have you used one before? Do they work?

I have rebuilt a few engines to just turn around and sell the car so I never really found it nessisary to buy a better quality part nor did i care, it wasn't going to be my ride.

So since this is my baby I was considering going the extra mile, do you even think it is worth the couple hundred extra for a better quality part? It's going to be my daily driver till I get my welding degree next year. Then she will be moving on to bigger and better things, I intend on making it my wheeling rig. Oh and it's a 4.0L, they don't even make the 3.0L for the b4000. eventually ill be swapping it out for the 5.0L! Now I'm just day dreaming.

 

I don't know your engine, but I once killed a Ford 302 due to a leaking valley or intake manifold gasket. I have never figured out how it could leak so much in a day of driving in the mountains but it was more than 3 quarts low at the end of the day. I never saw a loss of oil pressure, but it obviously had sucked air somewhere as the oil pressure at hot idle was nearly nothing after that day. I ran it a couple more years on thick oil.

If the valley gasket is your problem it is an easy fix with no need to pull the engine. It would look like a rear main seal leak, as would valve cover gasket leaks, so be sure you have ruled both out before you pull the engine. Head gaskets are unlikely to be your problem, but find the source of the leak and fix that specifically.

 

Yeah maybe I will start by taking it down to the intake manafold gasket before I even go and buy anything, I was planing on doing the head gasket set any ways, we will see how it goes, I just got to remember not to get to far ahead of myself on this. wouldn't that be sweet if I didn't have to do any of those lower gaskets and the rear main seal. Well I'm going to keep my fingers crossed.