'97 Corolla oil burn woes


#1

I have a 1997 corolla 1.6 with 215k miles on it. and put a new head gasket in about 500 miles ago. Along with the head gasket I replaced a cracked exhaust manifold, water pump, the (yes) original timing belt (what’s the record?) and put in new fuel injectors as well as replaced the valve seals. I also replaced the crank seal, water pump, and put in a new pcv valve, wilres and rotor.

The old head gasket was leaking oil, not coolant, and there were signs of heavy oil burn in two of the 4 cyls (1 and 3) with a lot of white deposits on the plugs and exhaust vales. I used a brass brush to clean off the valves, but did not lap them when I put them back in. The new valve seals seemed to go on fine and I applied a light coat of grease to make sure they were lubed at startup. I didn’t want to have the head shaved, and didn’t want to lap the valves because I didn’t want to change the compression so much that it would cause the rings to suffer when I got it back on the road.

I put the valves back together and coated everything with assembly oil before putting the valve cover on. Startup went fine and no C.E.L., no smoke.

400 miles later I checked the oil…1 quart low. I thought, ok…galleries in the engine are now full, and added a quart.

Next morning I notice a blue puff from the tailpipe on startup. Hmm…valve seals not worn in yet?

A hundred miles later, and a blue puff each am., I’m on my way to work and the oil light comes on. I stop. No oil. Put in two quarts and drive to a gas station, put in 1 more. It’s full. Drive to work ten miles, still full. Drive home from work, 15 miles, half-quart low and lots of blue smoke when accellerating post-decel, especially at the bottom of a hill when starting up. But no blue smoke at idle, even hot (when I got home). Idle two minutes and give it gas…blue smoke. Give it more gas…no smoke. No water in the oil, and no oil in the radiator…clear green fluid. No copious leaks on the ground, even after a few minutes of idling.

I have two, maybe three thoughts and I’m open to ideas.

  1. Valve now not sealing because I brushed away carbon deposit allowed compression to blow past the valve seat and pop off the seal, so now I have a valve with no seal? Possible. Could even happen to more than 1 valve.

  2. Oil return gallery plugging and oil is building up under the valve cover, causing it to drain down the valve guide. Could happen, I suppose.

  3. Crankcase vent system plugging? A quick check of the pcv hose showed it to be reasonably dry, but I could check the intake chamber (which did have a lot of carbon in it before the head gasket change.

I’ll pull the plugs and see if one or two cyls show oil combustion deposits, or if all do. Also considering a compression check, though I think the rings are ok based on the way the blue smoke is showing itself on cold start and when accelerating uphill.

And finally, still no C.E.L. The car starts and idles fine, though on the highway it does “surge” a bit (presumably this is when oil is hitting a cylinder?)

Thanks for your thoughts.


#2
  1. Coolant introduced into the cylinders by the bad head gasket damaged the cylinder walls and rings.

If I had pulled the head on an engine with 200K+ miles I would have first checked the cylinders for a wear ridge.
If the cylinders had wear I’d go looking for a used or rebuilt engine.

Otherwise take the head to a machine shop to get it refurbished:
Lightly mill the deck to remove any damage from the bum gasket and make sure it’s flat.
Clean up the valve seats and check valve guide clearance.

While the head is in the shop I’d also “freshen” the bottom end:
Drop the pan, remove the pistons, lightly hone the cylinders, replace the rod bearings, check the main bearings, replace the rings.
This engine might have updated pistons available from Toyota.


#3

Thanks.

The previous head gasket did not leak coolant, but there were signs of oil combustion in two cyls, with old valve stem seals leaking, The cylinder walls showed no signs of excessive ridge or wear. Still wondering why the massive occasional oil burn now. Newspaper under the car all day collected no oil drops. Dry underneath, and new head gasket and valve cover seal is dry all around. But it certainly seems that a wet/dry compression test is in order. If that shows an issue I’ll certainly do a complete tear-down.


#4

I believe this era of 4A-FE engines had a history of oil consumption. And I believe the problem is that the oil control rings get stuck


#5

Thanks, db. The research I’ve done shows that '98 - 2002 models had this issue, not that it couldn’t happen on this motor. But would that explain the intermittent oil burning? (It might certainly explain the mass consumption). Would a wet/dry compression test reveal this issue?


#6

The 98-02 had the 1.8L 1ZZFE engine that had the piston problem, the 97 I believe has the 4AFE as db said. The biggest issue with all the “A” series engines were the front crankshaft oil seal. It should have been replaced when the timing belt was replaced. But at 200k, if you pull the heads, you need to redo the bottom end as well, they will burn oil afterwards if you don’t.


#7

keith

I’m not sure why you keep bringing up the front crank seals on the A series engines

My family and I have had several cars with A series engines over the years. And the seals were not a problem. We replaced them at every timing belt job. And they were not a factor as far as oil loss/consumption goes.

I seem to recall you had some source that listed the crank seal as being problematic . . .


#8

@Studeboy‌

If you spend some time googling, you will get many hits in regard to 7A-FE and 4A-FE oil consumption due to stuck oil control rings

There are a few websites where guys have torn their engines down, on the stand. They post very good pictures, which clearly show the stuck oil control rings. In addition to cleaning the pistons and grooves, honing the cylinders, removing the ridge and replacing the rings

Some of these guys have posted back months later, with positive news that the oil consumption was drastically reduced

I have also read, on numerous forums, that stuff like marvel mystery oil and sea foam does NOT work to free up the oil control rings

I don’t mean to sound all negative

I’m just reporting what I’ve found. The reason I’ve come across this stuff is that some of our most recent Toyotas were a Celica with the 7A-FE and a Corolla with the 7A-FE. Both of these cars were well taken care of, yet they consumed oil with a vengeance, from day 1


#9

As a reference point, my 92 Corolla, 4afe engine, w/200K hasn’t experienced any oil use problems. dB is experienced and knowledgeable on this topic so OP should consider dB’s advice.

It sounds like you took a calculated risk in adopting some short cuts when you did this job. No worries, I’d probably have done the same thing. whaat’s the worst that could happen, you’d just have to remove the head again. ffffft … you’ve done that job before already, no problem doing it again.

A wet/dry compression test and a leak down test would tell you straight away if the valves and rings are not sealing properly. I’d start with that. If that test doesn’t turn up anything, I’d adopt a positive attitude so my suspicion is the valve stem seals were not installed correctly. One test which would tend to confirm this is if there’s a big puff of blue-ish smoke when you first start the engine in the morning, then it goes or almost goes away after the engine has been running a few minutes.

It’s possible to replace the valve stem seals without removing the head, right? You just have to pump compressed air into the cylinder to hold the pistons valves up while you do it. If it’s not the valve stem seals then you’ll have to remove the head again and check the items mentioned above, esp the oil control rings.

Edit: hmm … if I didn’t want to remove the head but thought it was the oil control rings, what would I do? I might try a dose of 100% synthetic oil and see if – after a while – that would clean things up enough to start to free them.


#10

George

For several years that I owned my previous oil consuming Corolla, I was using Castrol full synthetic.
In my case, it changed nothing


#11

Thanks to all above. Calculated risk is about the right description.

One poster mentioned the front seal, which I did replace when I took off the water pump.

I should know more by the end of the day today.

Much obliged.