Oil questions

Switching from years of conventional to synthetic will clean out lots of junk and can cause the engine to burn oil or leak. Switching to conventional is ok but you just don't have the benefits of synthetic.

At 175k it's probably ok to stay with synthetic if that's what was in it.

I'll have to check what I'm running but it's conventional break in oil in a newly rebuilt engine. I'll switch to synthetic.

Hmmm.. sounds like the oil is already getting past the rings and valve guides. If the seals are leaking then you'll see oil puddles. If it's consuming that much I'd go with conventional oil to save money but I doubt it will seal anything to stop the consumption.

Glad you caught that one in time. I bought my YJ with a blown motor because that pressure switch failed and was blowing oil out at about 1/2 quart per minute. It had 98,000 miles on it when it failed and needed a major overhaul.

I did all the all the removal and assembly and had a machine shop do all their work on the head and block. Overall cost was about $1100.

SirDoopYJ said:

I will keep trying to narrow it down. Hopefully I dont have to end up rebuilding so early into owning it. Thanks for the help!

Click to expand...

Forgot to mention Mine is a 4cyl 2.5L. Try a compression test for ring wear. Front and rear crank seals are not too impossible with the 4.0 had a valve job only can safe a lot of money. Get it up to speed, take you foot off the gas and let the engine act as a brake to slow you down. Then step hard on the gas and if you see a puf of blue smoke behind you then the valve guides may be bad.

Oil pan and valve cover gaskets are big leakers and the right way to fix it it to remove them and reseal with a new gasket or silicone. Over tightening the pan or cover bolts often causes them to leak even worse because it can distort the metal.

What you can try is warm up the engine slightly and spray it down top to bottom with a can or two of engine degreaser. Let it sit then spray it off with a garden hose or light pressure washer. Just try to avoid major electronics like the distributor, alternator, and computer, just get the engine. After rinsing let it dry and start it to dry out the rest. If you plug wires are not really old there shouldn't be any issue if they get a little wet.

That should be enough to see where any fresh oil is leaking from.

On the 5-speed that thin plate is just a cover plate to keep dirt, mice and cats out from around the flywheel. The automatic looks the same in the pic but someone else needs to verify that. Nothing structural and it lets oil or water drain past it. That spot in the photo is where oil will drip from and it could be from the front, top, sides or back of the engine and getting blown back there. A few drops can travel a long way.

If the engine is clean and it's dripping from behind that plate it could be the engine rear main seal or the transmission front seal. I don't know about automatics of if torque converters leak. That plate does come off by removing the bottom bolts and it slides out.

Engine oil is usually black unless it's clean new oil and transmission oil looks new but has different colors, gold if oil or red if auto-trans fluid. You'll need a white paper towel to help decide the color.

kid we're friends with needed a car....cheap. he bought one of the old fleet cars where i work. ford fusion, with 300k.

full synthetic from day one. still on full synthetic...2 and a half years later. just had all the seals and gaskets redone. mechanic is still shocked how good everything looks.

if you're really freaked out, go with synthetic high mileage.