Great Compression: Uses Oil

[Macword]

'95 Terc...168,000 miles. Compression is 180 across all 4 with 3 or 4 engine turns. It goes to 190 with 5. Plenty of pep, but still hesitates and surges at low acceleration and cruising RPM.

It does not drip or lose oil externally. But it's using a quart about every 800 miles...too much for my tastes. I've got a high mileage CRV and Toyota truck that don't use any oil.

Any thoughts?

[MR2Jedi]

Worn valve seals.
Oil, in very small amounts, leaking past valve seals into combustion chamber. Not enough to cause smoking, but enough to notice between oil changes. Doesn't sound serious right now, but they will continue to deteriorate.
I say let it go until it starts to smoke. Then remove the head and replace seals, do a valve grind and resurface and new HG . It'll be like new again.

[96paseo]

You can use a higher viscosity oil say like 10W-40 or 15W-40. It will help slow down the oil consumption.

[MR2Jedi]

You can, but you would not get the proper lubrication because of the higher viscosity and it would excellerate the deterioration of the valve seals (and other internal components).

[scys]

I found this doing a search. My 95 tercel does this, it smokes on acceleration, then goes away after I drive a bit. I have a couple of questions:
1 How do I replace the seals?
2 What is a valve grind?
3 What's HG?
4 Would I do a seafoam before I change the seals?

Cy

[scys]

Just re-read the post, does your car randomly stumble hiway speeds. I have 215 000km which is the same milage.
Cy

[Macword]

Once I'm at highway speeds, the car runs fine. It stumbles, hesitates, bucks, jerks, and otherwise irritates me at slow acceleration and slow cruising.

I'm inclined to agree that the oil consumption is due to valve seals, given the high compression.

I wonder if the hesitation, etc is due either to a bad distributor pack, or dirty or faulty injectors.

[96paseo]

Originally Posted by scys

I found this doing a search. My 95 tercel does this, it smokes on acceleration, then goes away after I drive a bit. I have a couple of questions:
1 How do I replace the seals?
2 What is a valve grind?
3 What's HG?
4 Would I do a seafoam before I change the seals?

Cy

1. Remove the cams and pull the head. Disassemble the lifters and valves, then punch out the old guides. Put in new ones. May as well get a re-man head if your not into spending a lot of time on it.
2. Re-surfacing the valve seat and the head.
3. Head gasket.
4. Seafoaming will not provide any benefits before doing a rebuild. Seafoam simply helps break down sludge in the motor.

[96paseo]

Originally Posted by Macword

Once I'm at highway speeds, the car runs fine. It stumbles, hesitates, bucks, jerks, and otherwise irritates me at slow acceleration and slow cruising.

I'm inclined to agree that the oil consumption is due to valve seals, given the high compression.

I wonder if the hesitation, etc is due either to a bad distributor pack, or dirty or faulty injectors.

Try cleaning your EGR. It can cause the bucks and jerks at low rpms when it gets clogged. Probably why it smooths out when you get above 3000rpm.

[33 dodge]

My engine had the same oil consumption. A freind of mine also had the oil problem. He put a reman head on his engine and guess what, it still burned lots of oil !!!!! I found a forum saying that the oil return holes inside the oil scraper ring on the piston are plugged with carbon. As the scaper ring collects the excess oil it is suppossed to run through the holes back in the block, but the holes are plugged so as the ring moves up and down in its grove it acually pumps the oil into the top of the cylinder. Engines that used high detergent oils did not suffer this problem.The engine will not show any signs of smoke as the cat will burn it off untill it becomes plugged.

[4speedsleeper]

Originally Posted by MR2Jedi

Worn valve seals.
Oil, in very small amounts, leaking past valve seals into combustion chamber. Not enough to cause smoking, but enough to notice between oil changes. Doesn't sound serious right now, but they will continue to deteriorate.
I say let it go until it starts to smoke. Then remove the head and replace seals, do a valve grind and resurface and new HG . It'll be like new again.

^^^^This is the best answer to your problem.

[sam333]

You can have good compression and still burn oil because of stuck/ worn oil rings( compression rings still seal but oil rings dont.
Puffs of bluish smoke on start up and at high engine vacuum( decelerating) are classic bad valve stem seals.
Burning oil at freeway speed ,constant throttle, lower vacuum(bad rings).
But if both are bad the two overlap depending on your driving.
You can burn alot of oil just through bad valve stem seals though.
You can change them without pulling the head , but its a pain.
You have to remove the cam/cams and you need a way to keep the valves from falling into the head( compressed air or rope trick)

[kinako]

Coming from the bike tech world, and I vote against disassembling your engine just yet.

-- Run a shock dosage of Seafoam to your fuel (2oz/gal), and run through a full tank of fuel. This accomplishes many things: cleans the back of your valves, removes carbon buildup on the piston crown, ring grooves and rings, and cleans the fuel system to the injectors. Be sure to change oil after a shock dosage, as all that buildup will go into your oil. Improvement?

-- If not, check vacuum lines, this is why: I found familiar bucking and hesitation on my 5E-FE Paseo, and sealing and confirming the MAP sensor hose to the manifold on both ends, the fuel pressure VSV lines going from the rail to the unit on the passenger side strut tower, and the brake booster line, prevented air from leaning out mixture in #3 and #4 cylinders, which was causing high oil consumption (lean mixtures can't provide the cylinder pressures to get behind the rings and make them seal (esp on hi-mile engines), and the E-series oil control rings are already notorious for going bad in less than 100K miles). I noticed my car consumes easily less than half the oil it used to in a typical change interval, to the point where I don't carry a bottle of Mobil 1 in the car anymore. It also gave me back almost 3 mpg.

-- Clean your IACV valve, just outside your throttle plate in the TB. Carb cleaner works great, spray liberally in that hole. Reinstall the air hose and clamp down, then let sit a few minutes. Start at WOT; will not start unless you open the throttle completely.

If these steps don't improve the problem fully, then resort to the hard part recommendations, these guys are solid. I've solved many, many running problems on cruisers and sportbikes, with just a dose of Seafoam. It won't fix mechanical problems, but it's just buildup that's the problem, this'll fix it.

There are motorcycle products like Yamaha Ring-Free that you can get from bike shops that are even more effective, but as before, if it's a valve stem seal that's worn, then you'll need to wrench. Worn guides are unlikely on DOHC motors with bucket followers like the 5E, since the buckets take all the lateral stress from the cam lobes, not the guides, as in the SOHC rocker-arm 3E (rocker arm pad/adjuster moves through an arc, while buckets move straight up and down, in line with the valve).