smcurro

The other day I noticed the oil pressure in my 70 olds cutlass was lower than normal. I checked the oil level and it was a whole two quarts low, which was quite surprising. I added oil and the oil pressure ran in the normal range once again. Coming home on the highway today I happened to look back to see plumes of blue smoke coming from my driver's side exhaust pipe. Since adding the oil I had driven 100 miles on the highway in 25 mile intervals. When I got home I checked the oil level and once again the oil was two quarts low. I haven't had a problem losing oil in the past. I have also noticed the car is running around 20 degrees hotter than normal. I checked my coolant and changed the old radiator cap but the engine is still running 20 degrees hot. I only see the plumes of blue smoke on the highway when I release the gas completely, it is not a constant cloud. I checked all the spark plugs and the tips look normal. I am sure the car was running perfectly a week ago with no burning oil and no oil loss. I have no idea what happened between then and now. Any ideas? What should I do about this problem? Thanks

z11375ss

Did you check for leaks? If the motor has a lot of mileage on it it could be the rings and perhaps bearings.$$ Good Luck!

smcurro

It leaks but only a little. Theres no way it leaked 2 quarts on the ground in three days..... Anyone know, if it puffs smog only when I am not touching the gas while I am on the highway, does that mean a valve is leaking? The motor has 120k miles. Thanks I appreciate it

rocketraider

Valve seals or guides come to mind, but before you tear into those, pull the valve covers and rod out the drainback holes. If oil can't drain back to the pan and is getting trapped at top of the engine, if seals/guides are marginal the high vacuum under deceleration will suck it into the chamber thru them, and burn off out the tailpipes. Oil consumption will increase.

High running temp will thin out oil and also increase consumption. You might want to check thermostat and cooling system including the fan clutch if car has it.

Then pull the plugs on that cylinder bank to see which one is oil fouled. That will be your problem cylinder.

smcurro

thanks! I'll get a new thermostat and check out the water pump, also I'll check out those drainback holes...one on each end of the head right? The fan is a flex fan...anything ever go wrong with those? I have a four core radiator in the car but ill check it for leaks...I'll also do a compression test... I checked the plugs and they all look good but I'm bet they won't look good for long judging from the amount of oil loss...thanks for the help!

Oldsguy

Don't care for the flex type fans. You could search that subject as there are quite a few posts and opinions concerning it. Some agree with me, others may not. I prefer the clutch type fan with a good shroud.

Lady72nRob71

Two quarts in 100 miles? Did I read that right?
That is way excessive, even if the engine is just running 20* hot.
I am guessing this has just started? Scary... How many miles?

My '72's 350 was running hot (225* or more) on my trip from Georgia to Texas (1700 miles) and she burned 2 quarts on that trip. I did not even know about her running hot until I installed my Rally Pac and confirmed it with an IR thermometer. (She had a 2 core radiator and a bad fan clutch...)

Does the 70 have a PCV system? Even if so and it was clogged, that would not explain smoke blowing out just one tailpipe though...

Anyway, I might guess the rubber valve guide seals have hardened and fallen apart on that side from years of oil and heat. This is not as costly unless the guides are worn, too.

Stuck piston rings and clogged returns (as mentioned) are possibilities also, hopefully the latter as it is the easiest to fix!

Long ago I have heard that an engine burning oil would run hotter due to lower octain of the oil... Any truth to this? I thought this was one of the reasons for not using too much oil in 2-stroke motors (aside from obvious smoking and plug fouling) and the need for high octain gas.

Would a blown head gasket do this? I cannot recall where the oil passages are... (Never even saw an Olds head gasket yet!) (I do not want to see MINE either...)

joe_padavano

I've had problems with blocked drainback holes causing oil consumption also, but given how quickly this has happened, I'd perform a leakdown test to see if there's a more serious problem.

smcurro

compression test revealed 225psi on 7 cylinders, 25 psi on back driver side cylinder........ I squirted oil in the 25 psi cylinder and it didnt up the compression at all so i assume the valve is all messed up.....guess I'm getting my heads rebuilt.................. Thanks for all the help though

88 coupe

Typo?

If not, you have another problem.

Norm

Lady72nRob71

smcurro,

Please let us know what you find out about that one cylinder - I actually lost some sleep thinking about what could have caused that...

I have plans for taking long trips in my 72 and that would be the (almost) worst that could happen. A starter or alternator or fuel pump I can understand and replace out of prevention (or replace myself on the road if needed). But internal engine mechanicals??
I guess that could happen on any car I suppose...

This is the first time I heard of such a sudden major failure on an Olds engine unrelated to poor maintanence, incorrect buildups, wrongdoings by mechanics, or driving them too hard.
I heard many people (including those in the Cadillac forums) saying the stock Olds engines were built like brick outhouses and would last hundreds of thousands of miles before major mechanical work was needed.

I just hope this was a rare case...
Anyone else heard of sudden major Olds engine failures in proper stock setups when driven 'normally'?

smcurro

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Lady72nRob71

Did your mechanic give a cause of the burnt exhaust valves? Lack of lubrication? Same valve each time?
I am questioning if this is something preventive measures could prevent...

Since you are pulling the motor, lots of "might as wells" will come up!
Resealing, painting, lots of internal parts, etc......... Lots of $$ for sure.
The previous owner of my 72 had the same thing done, but he did not have it painted. Now I get to try it with paintbrushes next year...

This would be a good time to replace the tranny front seal, too if needed.
When mine was all reassembled, the shop doing it messed up my front seal so she has a small drip now. Oh well; a drip pan works fine for now.

Keep us posted!

88 coupe

That is the kind of compression that breaks pistons, rings, heads, and ....

.... head gaskets.

That a faulty valve would cause low compression in any Olds (or any brand X) engine, is a no brainer. Ask him, how a "burnt" exhaust valve could cause your "overnight" increase in oil consumption.

Have them CC the heads and work out the compression ratio as soon as the heads are off.

And plan on replacing your #2 piston and rings, if not the whole set.

Norm

88 coupe

There is nothing he could have done, it happened before he got the car.

Norm

smcurro

what would ever cause it to have too much compression?? I know the previous owner put in some sort of big cam...could that be it? I don't know what kind of cam it is, he said he didn't even remember. Extra thin head gaskets? or could the heads been shaved an extreme amount? The car ran fine for the last three years with no internal problems until now. What are the compression numbers supposed to be around, Norm? The previous owner said he changed the head gaskets because the engine was overheating but it didn't help his overheating problem...which makes no sense...but he said he wasn't having any other problems with the head gaskets. He put a four core radiator in the car and apparently that fixed his problem because it has never overheated for me until now, even on the hottest days. The guy doesn't seem to know much about cars...only enough to be dangerous. I'm surprised he didn't mess anything else up...

smcurro

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88 coupe

No way to know until a competent machinist checks it out.

Anything I could say would be pure speculation. I prefer to deal in facts.

Another way of saying, he has not a clue? Either way, it does not change the fact that the engine is broken.

Did you expect it to run forever?

I would expect a high compression 350 to have been 180# (or so) when the car was new, and gas was 102+ octane. With todays fuel, 150# (or so) with a fresh rebuild.

More evidence showing he has not a clue?

How many miles between his "band aid" and your purchase?

What differences are/were there between the PO and your "driving habits?

It never overheated until it overheated, it never used oil until it used oil, and it never lost compression, in the #2 cylinder, until it lost pressure in the #2 cylinder.

You want answers? Make sure a competent machinist does the teardown.

Norm

smcurro

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88 coupe

No doubt.

If I changed it to read #12, would would it make any difference?

Here it is, again. This time, in its original context:

What is your point?

Norm

smcurro

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smcurro

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citcapp

Happy everything worked out for you. good luck on the 350 build

Oldsguy

good news on the update and having an extra engine around is always good.