Torkel

I need some help from the Gurus on this one, because it is driving me iiiinsane! Someone is going to die, if this is not resolved.

Problem: Oil is disappearing from the engine without a trance and oil temps are high.

Car is a US model -99, ~125K miles and with NO form of FI at all. Setup is in sign. Oil setup is: Sandwich plate for sensors (oil pressure and oil temp) and adapter for oil cooler system. Stock little water cooled oil cooler is removed! Oil filter is on the fire wall, thermostat next to the alternator and oil cooler (cheap model) is in front of the radiator. AC system is long gone! Oil is Redline 20W50.

The car drinks oil at the track and a bit more then I find reasonable. It lost over 1Liter (~1qt) on 2hour track use with 20W50 oil. Oil temps are too high: Cruising on highway (130km/h = 80MPH) results in an oil temp of 100C = 212F. On track, the temp goes up to 130C = 266F. Stock temp gauge doesn't move (but then it never does until you start to melt the block...)

Since last track day, I pulled the plugs and found them white and “hairy”, which I assume means: running lean. I sealed up all potential leaks in my intake, removed my PCV valve, added a breather filter and changed the plugs. Oil temp did not change after this. Plugs are too new to see if the engine is still running lean. I did a compression test with a brand new gauge and it shows excellent number. The car runs perfect, doesn’t smoke at all and the garage floor is free from oil spill.

I can’t help thinking the high oil temps and the vanishing oil are linked. Is my temp sensor screwed up? I do not think so, because the thermostat is opening at ~80C and all oil lines get hot, including the cooler itself. Can you boil away oil?

I am at a loss: Please help, oh thy smart people of MT.net! And do not tell me to get a better oil cooler, because this car shouldn’t need an oil cooler to begin with. (Sorry for the long post…)

EDIT: Just had a crazy brain-fart: If my air flow meter is bad, causing the car to run lean, could the ECU retarding timing a lot causing the higher oil temperature? That would explain both the lean-looking plugs and the high oil temps. Is that possible?

Torkel

No smart ideas at all? Perhaps the post was too long... I tried cleaning the MAF carefully, but it had no effect at all. Should I try to borrow a MAF from a buddy and test it? I kind of expect it to either work or be broken (which should stop the car) not to work but give the wrong values. Suggestions?

Rafa

iTrader: (22)

Remember that it's Memorial Day weekend in the States.

Gotpsi?

iTrader: (5)

Oil will definitely cook off especially if its not good oil, your oil temps don't seem to bad, Ive read posts of people with temps over 300F. make sure you run a good synthetic oil I would recommend Amsoil but it don't know about availability in your area. A good synthetic should drop oil temps some, also you can try using larger cooler lines and fittings for more flow to and from your cooler. I think mine are -8AN and they seem to work fine.

:Edit, you could also add a fan to your cooler Ive seen kits available to do that from Summit racing.

Torkel

As mentioned in my first post: I am running Redline 20w50. More cooling might keep the temps down, but it will not cure the actual problem. We are talking about a stock engine with no FI and oil cooling in 15C (~60F)weather.

Torkel

Good point. Didn't think about that. I'll be patient.

TrickerZ

iTrader: (6)

Running lean is likely due to an intake leak. Spray around with starter fluid and see if it causes the engine to rev. If so, you have a leak somewhere. If you have a MAF you can try, do it. It won't tell you anything if you don't have an AFR gauge, though. WB02 would be preferable.

Higher than normal oil temps could be caused by your higher weight oil. Try using a 10W30 to test it. The lower flow of the 20w50 may be causing it to heat up more as it goes through the motor. It may also be due to you running lean causing a higher EGT.

Do a leakdown test on the motor. You probably have a problem with your rings or something that can't be detected with just a compression test. Have you seen smoke out the exhaust? I'd assume you already checked your coolant for oil.

Not a guru, but those are the things I would try.

Torkel

Lean = high EGT = hot engine was my thought too. No smoke and nothing in the oil or coolant. I have used Mobil 1 10w30 earlier with the same temp levels. I have also looked at every connection, ever hose clamp and every little rubber hose connected to the intake and found nothing. But the trick with starter fluid sounds good! Havn't heard that one before. I can try that too. And I can probably borrow a MAF from a friend.

Gotpsi?

iTrader: (5)

you can use brake clean too, its less destructive to your engine.

Torkel

Good, then I don't even need to run to the parts store. I am traveling during the week but I will be testing this in the weekend.

Thanks for the input guys. To be continued...

Torkel

“Well, it can’t be the PCV, because I just changed that less then 500km ago...”

I tried the “brake cleaner trick” on the intake with no effect at all. So, in an act of frustration, I took apart the intake manifold, since the PCV after all was connected at the last track day. Guess what? There was a LOT of oil there. So in other words: The new PCV didn’t even last 500km. But I am glad to have found the reason for my oil consumption! From now on, the PCV will be connected on inspection day only. Next track day will tell if it is the true source of the problem, but the amount of oil in the manifold tells me, it most likely is. I don't care about the oil temps (high, normal, whatever) as long as the consumption is fixed.

TrickerZ

iTrader: (6)

I would think there's a problem with seals if there's THAT much oil going through your PCV. A catch can would be a good idea as I don't think a new PCV is going to solve your problem. From what I understand, the PCV problem is caused mostly by FI. Someone else might want to chime in as to what to do, but I would think gaskets, o-rings, etc. might need to be replaced and possibly valve sleeves. I've never rebuilt anything (though, that will probably be a project coming soon) so it'd be better if someone who has could give possible causes.

fooger03

iTrader: (2)

have you had your valve cover worked on? powdercoated? replaced?

being that you're not FI, it sounds like there may be a problem with your "baffle system thing" beneath your PCV valve. You should be getting oil "vapor" in your intake manifold, not a fair amount of liquid oil. The "baffle system thing" should prevent any significant amount of oil to actually see your PCV valve

Torkel

Thanks for the input guys. No, nothing has been done to the valve cover, but I did have it of when I re-shimed the head some time ago. But I thought the baffles things are fixed solid parts of the valve cover? Since it is an easy task, I could lift it and have a look. You never know what the PO have done...

The last thing I am going to do is to just buy a new PCV valve and put on. Getting the lower part of the -99s intake manifold of is a PITA!!

Torkel

So I have taken apart the coldside and got the intake manifold off (which was a PITA). As you can see on these pics, I have oil in the ports in the head and on the valves. Now, engine oil in the wrong place (such as: in the cylinders) is not something that hasn’t happened before in the history of the car, but I am not sure what the effect is when it is plastered on my valves?



Since it is summer and Miata friendly weather and since I don’t feel like pulling the head and since I have a track day on the 27th, I am planning on cleaning the intake ports with a rag, my finger and some cleaner, put it back together and run it. Please comment, you people who know more about valves and engines.

fooger03

iTrader: (2)

Somethings missing in that last post...I'm not quite sure what it is.

Did you get a chance to look at the internal PCV baffle(s) on the inside of the valve cover? They screw in with (IIRC) a phillips head screwdriver.

Torkel

The pics are missing! What, didn't you see that?!?!!

Havn't lifted the valve cover yet, but thanks for the info about the baffles. My prio one is to get the car cleaned up and ready for track day (minus PCV, of course!), so I started with the intake. I'll lift the valve cover when I get time.

04 Miata

If the baffles on the bottom of the cover were removed at some point but not sealed with RTV when they were reinstalled then your oil usage will go through the roof.

Torkel

I just had time to remove both upper and lower part of the intake manifold and get them clean and reassembled before my track day this Sunday. I drove it like a bat out of hell, giving it nooo mercy and it ran great. With the PCV plugget and a breather on the valve cover, the car didn’t take any oil . I will still lift the valve cover and finally get a look at the baffles, but right now… I am just so pleased.

magnamx-5

iTrader: (7)

torkel check your valve stem seals if this reoccurs it they have to much play or are weeping on you they could cause the problem.