So, you think you're an engine guru?

[98ACR]

Ok, here's the situation (with all applicable details)

My '94 ES has 175K on the original block. At 140K miles the T-belt snapped and the head was replaced with a reman unit. Prior to the T-belt catostrophy, the engine ran perfectly with no problems. After the head was replaced, the car ran great but smoked occasionally. I also began to lose an alraming ammount of oil. All oil leaks have been remedied with one exception being a slight seepage at the oil pan gasket which is truely insignifigant. Now I'm losing 1 quart of oil each 500 miles or so. The tricky thing is when I pull my plugs after 20k miles, they are clean, with a light tan color to the plugs and NO oil contamination or accumulation of deposits. A compression test was performed with cyl 1 showing 190 PSI, cyl 2 180, cyl 3 185, cyl 4 183. Values did not change signifigantly when oil was added to the cylinders. Obviously, the rings/valves are not my problem. And it dosen't seem like the oil is being burned. But I'm still losing oil fairly consistantly. And I'm getting a nice sooting on my back bumper. So, the question is: WHERE is my oil going???

[Diamndsr4eva]

ask seth. He would know... :D :D

[seth98esT]

Did the reman have new valve seals? When does it smoke?

[Goku]

Valve stem seals?

Also known as valve guide seals...

[seth98esT]

Usually if its the valve stem seals are bad, it will only smoke if you let it idle for a few minutes then start driving, like at a stoplight. Also what color smoke? I assume its blue.

[Goku]

Usually if its the valve stem seals are bad, it will only smoke if you let it idle for a few minutes then start driving, like at a stoplight.

Yea, you beat me to it lol :P

But then again, you don't always lose oil when the seals are bad.

[seth98esT]

Shouldnt be the valve seals at the rate he is losing oil. DId you check under the car to see if maybe it only leaks under pressure, while your driving?

[fuel]

I had a similar problem with my old '89 Galant with a 4G37 SOHC which had done 250k miles +.

My cylinder compressions were still really high (above 200 PSI) and there were no circumstancial oil leaks around the engine. I had replaced the valve stem seals when I reconditioned the head after it blew a head gasket. My oil consumption was fine just after the head was reco'd but about a month after I noticed it started using heaps of oil.

What had happened is after the head had been reconditioned, because it was in better condition than before, it was placing more strain on the rings and bearings than before.

It will most likely be the rings which are the culprit - even though they are sealing combustion gasses fine they still may be letting oil get through. Another thing which happens on higher milage engines is the ring to piston clearance increases and the movement of the rings actually pumps oil into the combustion chamber.

Talk to any mechanic, if you do a head job on an otherwise standard and partially tired big end you'll run into problems down the track. About 6 months after I did my head my big end bearings failed.

[98ACR]

If it's leaking outside the engine, it's spraying it straight down and leaving no residue because aside from the oil pan the bottom of my engine is clean. And yes, the head is 100% reconditioned right down to NEW valves and all new seals. It smokes when I first start the vehicle (sooty black smoke, usually accompanied with considerable condensation) which lasts until the engine reaches operating temperature. It also smokes the first time I redline the engine after it's sat for a signifigant time, but after that the smoke stops...

Again, at the rate I'm losing oil I'd be leaving a smoke screen that would put James Bond to shame and I'd be fouling plugs left and right. Neither of those circumstances are occuring.

So far I've stumped 3 master techs....good luck with this one

[fuel]

Sorry forgot to add I was going through about a liter of oil every 500kms sometimes even more, and I could never see my car smoking nor did it foul plugs also. If you get someone to follow you they will probably see puffs of blue smoke but just not enough to be visible to you from the rear view mirror.

This always usually happens after you place a reconditioned head on a tired bottom end. I'm sure your rings, despite sealing combustion gasses, are still letting oil through. You'll probably find you will run a big end bearing or two within a year - I know I did on both my 4G37 and my 6A12 after heads were reconditioned.

Another thing to consider is the grade of oil you are running. On a 175K bottom end you should probably consider switching to 20W50 grade oil, especially if the temperatures are warming up in spring/summer there. Were you running the same grade oil before and after you did the head?

[98ACR]

As long as I've had this engine I've ran 10w30 Castrol GTX.

I really don't think this block is going anywhere anytime soon, it's still amazingly strong and I've been dogging it for 35k miles since the engine re-build and it always just seems to take it all in stride. It just keeps drinking oil.

P.S. I had a co-worker follow me today....NO smoke out the tailpipes. But there is some brackish liquid that is spewed out of the tailpipes when I get on it hard. Likely the same stuff I see when I first start it...it's kinda like oily water... wierd :?

[fuel]

Well I think running 10W30 is your problem right there.

Sure 10W30 would have been a good oil to use when it was brand new out of the factory when the engine had tight clearances. Now it has done 175,000 MILES so things are going to be a bit worn - including the rings!

Switch to thicker grade such as 15W40 or 15W50 etc - you WILL notice the oil consumption will be reduced.

Speak to any good mechanic, he (or she) will probably tell you the same.

[fuel]

Oh another thing, first you say the head was reconditioned, then you said the engine was rebuilt - which is it? A reconditioned head does not equal a rebuilt engine, infact as I've explained above reconditioning a head on an otherwise worn bottom end which hasn't been rebuilt will cause problems just like you are experiencing.

[Goku]

Totally agree, 10w 30 is not the right oil for you to be running in a car with that high milage on it...
I run 5w 50 in my VR-4, but thats only because I know it is ok in it's current state.

[manybrews]

oil viscousity has nothing to do with it.

if you starting loosing oil after the repair, there are only 2 possibilities. One involves either a crappy valve seal replacement job, or more likely several cracked valve guides.
the other is that the engine has been incorrectly torqued, and the cylinders are now distorted. Truth be told, the 94-95 blocks had a tendency to use oil anyway due to slightly out-of-round cylinders, but that should have started years ago.
nope, chances are its a shitty head rebuild. you can EASILY go through that much oil from valves alone.

[fuel]

Oil viscosity does have something to do with it! The thinner the oil - the easier it will be to escape passed worn rings, valve stem seals, crank seals etc.

At 175K miles the engine would be getting a bit worn - and it's a known fact if you rebuild the top end of your motor without doing the bottom end, the bottom end will eventually suffer! It's happened to two of my engines, and have seen it happen to countless others! Most engine shops will avoid just doing a head-job now, or at least warn the owner about putting a reconditioned head on a tired block.

All I'm saying is change your oil from 10W30 to something a bit more suited to the age/milage of the engine such as 15W40 or 15W50. The oil consumption WILL drop.

[Goku]

x2

We're not saying it's the only cause of the oil loss, but it is contributing to it. Oil viscosity can have a lot to do with many problems people are finding they are having with their engines. Be it oil loss to noisy lifters etc...

[manybrews]

pretty sure I know a thing or 2 about mitsu engines..... and you're NOT losing a quart every 500 because its 10w30.

I use ONLY 5w30 in all my cars, and im now on a second diamante with over 200,000 miles.

I use less than a quart every 1000 on one of them, and a quart every 2000 on the other.
no, the problem stems from either an improper repair, or something else. changing from 5w30 to 10w30 to 15w40 will have little to do with that.
truth is the thicker oils are generally bad for an engine.. they cause excess drag and wear, and usually will suffer a loss of milage and horsepower.

[98ACR]

truth is the thicker oils are generally bad for an engine.. they cause excess drag and wear, and usually will suffer a loss of milage and horsepower.

and a prize for the winner....

I was just testing you guys, thus the name of the thread.

It's the valve seals on the exhaust side. I've already corrected the problem and no more smoke, no more oil consumption. Just a test

[Goku]

pretty sure I know a thing or 2 about mitsu engines..... and you're NOT losing a quart every 500 because its 10w30.

I use ONLY 5w30 in all my cars, and im now on a second diamante with over 200,000 miles.

I use less than a quart every 1000 on one of them, and a quart every 2000 on the other.
no, the problem stems from either an improper repair, or something else. changing from 5w30 to 10w30 to 15w40 will have little to do with that.
truth is the thicker oils are generally bad for an engine.. they cause excess drag and wear, and usually will suffer a loss of milage and horsepower.

*sigh* What part of we are not saying thats the sole cause of the problem did you not understand ?

I also know a hell of alot about mitsu engines seeing as 1: I used to work for mitsubishi and 2: my father still does and has done for over the past 30 years.

Age of a vehicle and it's engine does play a part in what viscosity of oil you use, esp in cars that have done high milage.
You may take better care of your engine hence why you don't lose any oil, but thicker oils are Generally better for older engines that have been worn out a bit over time.