My 1999 Chevy Prizm may be an oily lemon

I bought a new-to-me '99 Chevy Prizm auto (Corolla twin) with 120K on it 29 days ago. (Which means, of course, that the far end of the warranty I got from the dealership expires tomorrow.)

Everything seemed fine for awhile. I got the car on a Wednesday, drove it to work Thursday (some brake sounds, and a PO420 check engine trouble code that I had diagnosed at an auto parts store, but it put itself out 70 miles later – and yes, I know that’s the cat), brought it to my mechanic Friday. They checked it out, changed the brake and power steering fluids, asked if I wanted them to machine the rotors and drums so they’d fit together better (and not make noise), but I said no, those were under warranty and I’d take it back to the dealer. Everything else seemed fine.

Took it back to the dealer the following Monday or Tuesday for the brakes. They said they never machine parts, only get new ones, and these were already new. They’re a pop-and-son place with maybe 35 cars from auction or trades at a time. So they adjusted the e-brake, cleaned the non-working cigarette lighter (for GPS), and sent me away.

Two weeks later, I’m at work with a client in the car and the oil pressure light blinks, once, while I’m stopped on an incline. I’ve owned an old Volvo and listened to Car Talk, so I pulled over and there’s no oil on the dipstick…two quarts later, it barely reaches past the min level.

(I know, I know! How could I have owned the car two weeks and never questioned the dipstick? But I’d just had it checked out three times by two different places, and my old Geo Prizm was always so beautifully dry and reliable…)

NEVER any smoke, and NEVER any drips – though now the PO420 codes that have been flicking on and off make a bit of horrifying sense. I drive immediately back to my mechanic. He puts it on the lift, hoping for a giant oil leak – nothing but internal old leaks – and puts some dye in it, tops it off, tells me to drive it a bit and keep checking it and we’ll see where we are in the a.m.

I drove about 100 miles, lost some but not much oil, so the mechanic gave me the go-ahead to take it on a trip I’ve been planning, about 1000 miles round-trip, but to keep my eye on it, obviously. Over the course of the trip, the car requires 3 quarts of oil.

Back to the mechanic, who replaces the gunked-up PCV valve. (But do those ever get gunked unless there’s something bigger wrong?) Back again today, two days later, for the regularly scheduled oil change, because despite pouring 5 quarts down the hole I know the sludge hasn’t come out yet. My mechanic put in an additive he’s hoping will help.

Meanwhile, I put in an email to the dealer that sold it hoping to get an honest reaction of “gee, we want to make this right” in the event the small fix-it solutions don’t work. We’ll see. In the meantime, I’m still driving it and hoping for the best.

But barring the best, we’re looking at likely valve stem seals or bad piston rings, right? And for those jobs, my mechanic says I might as well get a new engine. It also seems obvious to me that either of those issues would have been plaguing the car when the dealer sold it to me – which to me means I should get some kind of refund, right?

If the small fixes don’t work, and if the dealer won’t refund or compensate or whatever, how long might I have with this car, if I keep pouring oil down it? SHOULD I get a new engine? Or should I drive it into the ground and look for a new car along the way?

Are there alternatives?

Unfortunately, it is very common for the Prizm/Corolla twins of this era to drink a quart or so of oil every 200-300 miles. Even with reasonably good maintenance habits, these engines tend to sludge up. Your mechanic should pull the valve cover off and take a look. Often times, cleaning out the oil galleys in the cylinder head and installing new valve guide seals will slow the rate of consumption to a more reasonable rate. I certainly wouldn’t expect it to stop altogether, since the car has already been run out of oil an unknown number of times (not every time by you, but also by previous owners). If I owned one of these cars and it used less than a quart every thousand miles, I would be ecstatic.

Hmm…valve guide seals, you say? I’ll have my mechanic look into that. I’ve heard about the sludging problem, and heck if this turns out to be normal I guess I’ll just live with it if it will live with me.

I only let the oil go low that once (since I’ve only had it a month), but who knows what previous owners did. It was a lease the first three years.

As long as I own it, it’ll be drenched with oil.

Run a compression test. It may be that you need a new engine or a new car. Since your warranty is DOA tomorrow you may be up the creek on this one.

The P0420 code seems to plague Toyota’s and the Corolla in particular and it is often NOT the cat but the rear O2 sensor or a leak in the exhaust system.

I have not seen many complaints of sludge with this engine. That applied mostly to the V6 engines and some 4 cylinder engines in the Camry of this era.

If you have blue smoke coming out the exhaust for the first 5-15 seconds after startup, then you need new valve stem seals, otherwise, probably not. If the engine is leaking oil, it would be most likely the front crankshaft seal, front cam seals, valve covers and oil pressure sending unit in that order. Your mechanic would easily find any of these leaks.

If it is burning oil at this low mileage, then the engine has been very poorly maintained. If that badly maintained, and the clogged up PVC valve kind of indicates this, the engine may have a buildup of sludge under the valve covers, not because it is prone to it, but any engine can sludge up if the maintenance has been bad enough. Removing the valve covers and mechanically removing the sludge, insuring the drain back holes are clear and changing the oil could help. I would recommend that.

As for this model being a notorious user of oil, I disagree. The earlier Corolla/Prism models with the A series engines were. But even they didn’t become a problem until the got north of 150k miles and they usually leaked more than burned oil.

How did you buy a used car without having your mechanic check it out first? You say you listen to Car Talk, but Tom and Ray tell the same thing to every caller planning to buy a used car: “Get it inspected by your mechanic FIRST, as if your mechanic is considering buying the car himself.”

There are those who are willing to forgo this inspection for certified used cars (against Tom and Ray’s, and my advice), but you bought yours from “a pop-and-son place,” which, in my view, are less trustworthy than new car dealerships (if that’s even possible). Even certified used cars should be checked out beforehand.

This is a 12-year-old vehicle! Why would you assume it was in good shape without confirming it first?

My advice is to read your warranty and sales paperwork to find out what your rights are. If the car was sold to you “as-is,” you might have to chalk this up to one expensive lesson, and pay for the repairs yourself.

In my experience this engine is not prone to sludging. The V6 was, and I suspect that it simply wasn’t as tolerant of neglect as most engines are. I suspect most of the V6 sludge problems were induced by poor maintenance.

You bought a 12 year old Corolla with an annual average of 10,000 miles, indicating that much of its life was spent in stop and go driving. That’s much more wear inducing than highway mileage. You have to expect that it might be tired and use some oil. I’d start by doing a compression test on the engine. It’s entirely possible that the engine is just plain tired. The cylinders are probably worn, the oil rings have probably lost most of their spring tension, and the valve guide seals are probably shot. If the compression test yields poor results, I’d just carry a case of oil with me and keep driving it. If the test yields good results, I’d consider running some oil desludging additive through it and them cleaning out the return and perhaps changing the valve guide seals. That won’t affect the cylinder wear, and you’ll still use some oil, but it might help reduce the amount. Anything more than this would head you down the road of a rebuild, and unless the car is in outstanding condition that would not IMHO be a good investment.

@Whitey – So your argument is that if my mechanic had looked at the car a day before he did (since I brought it down to the mechanic less than 48 hours after putting down the cash), he would have wanted to run a compression test? Despite there being no indication of leaks and no smoke (ever) coming out the back? Because although I agree that having a car checked out before buying it is definitely the way to go, and I know an independent mechanic is the way to go when it’s being inspected, I’m not sure any of that would have helped me.

What I DID do, before driving it the 75 miles to my mechanic to have it inspected as soon as I could, is go through the list of safety checks with the on-site mechanic, test drive the car, check out the Carfax (which I know doesn’t include most stuff), look over all the warranty info, which included a warranty on the engine and trans, go through the usual list of stuff to look out for, called my mechanic for advice, and immediately got in contact with my mechanic and the dealer at the first sign of (brake) trouble as well as scheduling it for the earliest possible inspection.

I’m really not sure how the two days would have made any difference in this case. If I’d thought the answer to my question was “you were just stupid,” I wouldn’t have asked it.

Now if you’d pointed out (as I already did) that I really should have been checking the dipstick and not just for leaks or spots on the ground or smoke from the exhaust, on a daily basis when I first got the car, I’d be singing your tune, there. That WAS just stupid, and I see that now.

And if your point really IS that my mechanic, or any mechanic, should do a compression test on any car as a part of an initial inspection, then that’s helpful advice that I’ll apply to my next car purchase. Heck, I may require it anyway, because clearly my budget doesn’t allow for a car built in this millennium and anything built before might have these same issues.

@the same mountainbike – Yeah. It was driven about 60K during its 3-year lease initially, but the average mileage over the last nine years has been just under 7,000, according to the Carfax report I got on it. My mother used to drive her cars very little, and she ended up with a pretty tired Ford Taurus pretty early in its mileage, so that situation is familiar to me…

I did have a choice between this car and the same model with 165K on it, which looked just as good as this one in all the apparent ways (test drive, kicking the tires type stuff), and I called my mechanic to see which car I should choose. He advised me to buy the lower mileage car, since we had no more info on either car’s maintenance history, and when I brought it in two days after I bought it, the guys at the shop said it looked good for its mileage. This obviously gave me what might turn out to be a false sense of security.

Honestly, in my area, the only choices during the window I had to buy a new car (before rental fees for going to work began eating severely into my already stretched and limited budget) seemed to be cars with well over 150K, sometimes with over 200 or 250K. This seemed like a better choice than those, though I realize any used car is a risk (certainly in my budget range). I’d been hoping that a dealership warranty would protect me better than buying something off a lawn, and I’d also put a lot of faith in Corolla engines – my old Geo Prizm drove 20K a year like a champ until the tranny blew, and that was 20 years old.

But any engine can be ruined by poor maintenance.

My mechanic also says with this car, doing serious work on the valve stem seals or, heaven forbid, piston rings, I’d probably be better off getting a used/rebuilt engine. I’m not sure how I feel about that, since obviously the car ISN’T in excellent condition – but on the other hand, if I got a “new” engine, I could make sure all the parts were inspected/certified/well-maintained going forward. It’s as close to a new car as I can get on a shoestring budget, right? Or are there things I don’t know about the shady world of rebuilt engines? Ways to hide horrible problems that wouldn’t show up until after the warranty?

Oh – and I smiled when I read you guys pointing out to me that I own an (elderly) 12-year-old vehicle. I thought I was moving up in the world getting a car that young!

My last two cars I got at 17 years old each: one was a money pit, and one was a peach. : )

Sometimes we make the best decision we possibly can and it doesn’t turn out perfect. We all do it. That’s part of the human experience. God knows I’ve made bigger mistakes.

If the compression does prove the engine to be worn down, and the rest of the car is in excellent shape, a rebuilt long block (with head) would be the most-guaranteed way to go, but remember when deciding that you’d be putting a new engine in an older vehicle. A good low-mileage boneyard motor is often the best option for an older car.

But you have a way to go before facing that bridge. First have the engine checked out and if there’s a PCV valve (my '91 Camry didn’t have one) change it. A stuck PCV valve can allow pressure to build in the crankcase and force seepage out the main seals, which at this point are probably pretty tired themselves. This is especially true in an older engine where the blowby is going to be greater.

Another test you could do is to have a friend follow you on the highway and tell you when smoke comes out. If it comes out on deceleration and the compression isn;t too bad consider doing the valve seals. During deceleration, the cylinders are still trying to pull in the same amout of air but the throttle plate now acts as an obstruction. That causes vacuum in the cylinders to spike, and that’s when they’ll pull oil past the valve stem seals. This isn’t always definitive in modern cars because the converter can trap much of the oil, but you have nothing to lose by trying it.

If in the end you search for a rebuilt engine, be aware of the difference between “rebuilt” and “remanufactured”. A “rebuilt” engine is made good running again, a “remanufactured” engine has all the wear items replaced and is brought back to original specs. The latter is generally more expensive, but the engine will be better. Whether it’s worth it is a personal decision.

@keith – I figured the P0420 was from the catalytic converter only after it seemed like the car might be burning a lot of oil…because where would it be going if there’s NO smoke and no leaks? (I had someone driving behind me for three hours at one point, and she never saw smoke either.) The car doesn’t run rough at all like I would have thought it would if I had a hole in the exhaust (or make any weird noises), but I honestly know next to nothing about diagnosing the exhaust system.

I suspect at this point that whoever sold it to the dealer (because they didn’t do the cat, or at least it’s not on the service record, nor warranteed like the brakes they put on were, and the dealer today said they hadn’t replaced it) put on a new catalytic converter possibly to mask this very issue. I admit I’m baffled by that level of oil consumption, but my mechanic agrees that if it’s going anywhere, it’s probably being eaten by the cat right now…until the cat fails down the road, at which point I may start seeing the colored smokes of a bad engine.

What I can’t understand about that scenario is why the check engine light would ever go off again. Can the cat really handle that much oil burning through it (for now), except occasionally when it signals an error code?

It’ll continue collecting the soot until the soot’s coating prevents it from effectively contacting the NOx molecules.

Don’t yet rule out the oil being pushed past the main seals. That only happens when the engine is running, only when the blowby is pressurizing the crankcase, so it can be mysterious to prove.

Until you get the compression checked and check the PCV valve (if there is one) you’re sort of “shooting in the dark”.

Although “reading” the sparkplug is easy and might also be revealing.

@the same mountainbike – Thanks, mountainbike! That’s very helpful, to hear the distinctions between rebuilt and remanufactured, and what my options would be. I’m going to save that against the possible day when I need it.

My mechanic did change the PCV valve (for free! What a guy), and the next day there had been some oil loss, though I didn’t drive it 1000 miles to really test it out. He was hoping it was pressurizing the oil improperly, too, and that the change would fix it. Yesterday I got an oil change, and I almost didn’t recognize the color! Sweet honey brown, eh? I’d been looking at blackened gross stuff the whole past week.

I’ve driven it probably 70 miles or so to work and back since last afternoon, and so far it seems to be holding the level, though the oil’s a tiny bit darker on the bottom of the stick than it was yesterday. But if the oil in there was sludgy, that could be extra leftover. Or maybe it will all blacken over the next thousand miles…I guess only a thousand miles will tell, with that one.

I’ve heard about “reading” the sparkplug, but I’ve never actually looked at one personally. Everything I know about cars right now has either come from the crash course I’ve been giving myself thanks to my current car issues, or has been taught to me by the idiosyncrasies of my old Volvo. (Has anyone else ever needed to find an 18mm heli coil to rethread their old oil pan? Honestly, that car!)

Maybe I’ll look up a diagram and see if I can figure out how to check 'em, or if it’s possible/a good idea with no tools and no experience. Otherwise, my mechanic said to bring her back after 1,000 miles or so to see how she’s going. The next step after this, if she’s still eating oil, is a compression test.

I’m thinking no matter what, I should probably be getting the oil changed on this car at less than 3,000 miles, to be on the safe side. Especially if it’s burning up to black – that can’t be good for the engine.

Also, I did call the dealer today. He said they couldn’t fix the cars of everyone who complained that they had had problems beginning within the warranty period, because their profit margins couldn’t handle it. Um, really? Wow.

I’m pretty sure that’s the closest I’ll ever come to hearing a dealer admit that they sell junky cars.

I’m also not sure why he thought appealing to my sympathies over their profit margins was a good call; obviously I don’t care as much about the dealership as I do about my own ability to get to work and back.

He did say to keep them updated, which I plan on doing – mainly for documentation purposes – and that if I ended up needing a new engine, he was “sure we could do it for less than your mechanic.” I never told him who my mechanic was, so I’m not sure why he thought that was definitely true. I’d never go back to that dealership for anything more complicated than another cigarette lighter cleaning at this point, anyway, so it’s moot. (And after their mechanic cleaned it, it stopped working the next day and I had to take it apart myself with a friend, anyway. Works fine now.)

But honestly that was kind of the response I was expecting. And reviewing the facts in how I purchased this car, and the good reviews it got all around from my own observations, Carfax, and my mechanics, I feel I probably would have bought the car off someone’s lawn for maybe $700 less…which means I’m only (emotionally) in the hole for $700 – and most of that was taxes and registration anyway. Though with a private seller, I would have known more maintenance history, and that would have been very helpful.

Lawns vs. Lots seems to be an age-old question in cheap, cheap used car buying. Maybe I should focus on making friends with some old ladies for next time.

To “read” your plugs, simply remove them, and compare them to this chart.

It can tell you if you’ve got excess oil flowing into one of the cylinders, too much fuel (which would eventually lead to rough running due to at last one cylinder not firing properly), overheating, etc, etc… It’s probably the most simple thing to check, and by reflex, every mechanic I know will do it when he removes a plug.


Update: Well, I haven’t checked my spark plugs, but since I had the oil changed, I’ve driven the car over 400 miles and lost MAYBE a third of a quart of oil…maybe, but possibly less. I haven’t needed to add any. And the color is still pretty good – rather than the blackened stuff I was getting on the dipstick before, it looks pretty much like honey.

I’m beginning to wonder the following:

  1. I see from another question/thread (and had believed myself) that following the specifications of oil weight given by the car manufacturer is the way to go – my oil cap specifies 5w30, which is what I was feeding the car on the 1000 mile trip where it burned through 3 quarts, not any great synthetic but just what I could get at the Target when the dipstick first went dry – but after the oil-burning, my mechanic put heavier weight with an additive in, which is what is currently holding strong…so should I continue the life of the car with heavier weight (in summer, at least) and more frequent oil changes?

  2. Could it really have been the PCV valve? Seriously? It seems like that’s the thing everyone tries first because it’s cheap, but I’ve never heard of it actually being the main problem, only a symptom.

  3. Could it have been the conditions under which I was driving the 1000 miles – all in 2 days, all around 65 mph – that caused the car to burn oil like crazy? If that’s the case, I think I’ll be renting cars for trips that long in the future, because that couldn’t possibly be good for the car, eh? My usual driving for work is probably half highway, half city, and very rarely do I take short trips where the car doesn’t warm up (less than 10 minutes).

I know 400 miles isn’t really enough data to go on, but I’m feeling much more optimistic than I was 2 weeks ago.

  1. Excellent question. Heavier base weight oil can reduce excess oil consumption a bit, but that does not mean that you were using too light a weight in the first place, oly that the engine is worn. I’d be reluctant to go beyond 10W base. Others might suggest 20W, but I’d be concerned that I was reducing oil use by the bottom end at the expense of proper lubrication at the top end (the valvetrain).

  2. yes, it could have been the PCV valve. The crankcase has a tendency to devellop pressure due to some of the combustion gasses blowing past the piston rings (a normal thing). This pressure if unrelieved can cause oil to seep past tired, worn main seals. Main seals are the seals at the crankshaft ends that keep the oil in the crankcase as the engine runs. They’re just rubber, and they can get worn, shrink, and shrivel. The pressure is relieved up through the oil return passages in the block and head and through the Positive Crankcase Ventilation (PCV) valve, wherein it then goes back into the engine bringing any crankcase fumes with it. If the PCV valve is plugged, pressure can build in the crankcase and force oil past the main seals.

  3. That could have been a contributor. If your engine is past its prime, the increased pressures induced by the constant higher RPMs can push oil past the main seals at a faster rate if the PCV valve is clogged. It’ll also allow more oil to be retained on the cylinder walls if the engine is burniing some oil anyway, and you’ll burn more.

Honestly, I think the engine is getting tired and you’re seeing normal signs of that exascerbated by a plugged PCV valve. Just watch your oil level, keep it above the fill line, keep the cars maintenance up, and you’ll probably get many, many more miles out of it.

And you owe you mechanic a case of his favorite hops. Far too many shops would have tried to talk you into a new engine (or a rebuild) rather than help you out like he has. The truth is that a tired engine will run many, many miles as long as it’s kept up and the oil level is kept above the fill line.

Thanks, @mountainbike!

You’ve affirmed the suspicions I had about the PCV valve – that it’s necessary and helpful to keep it gunk-free and working properly, but that it probably fails in conjunction with other things (like worn out seals). And I’m definitely ready to keep this car in regular maintenance.

They know me by name and sight at the garage, but it wasn’t until these issues and me actually doing research to understand what they were telling me (and what you guys have been telling me, and other people) that I’ve felt like I was participating in taking care of my car – so I agree, mountainbike, that I’m glad my mechanic didn’t try to immediately “sell” me a new engine or a rebuild (which he knows I couldn’t afford).

When I went in for the oil change, I brought everybody iced tea…Not quite on par with favorite beer, but then they WERE on the job! (And my mechanic is diabetic, so baked goods are a nonstarter.)

Since I saw the dry dipstick in that Target parking lot, I’ve known I was in for some trouble, but it’s nice to think that with some better care than it probably had been getting, this car will still probably last me awhile. I’d always been planning on driving it into the ground, but at least now I don’t feel like I’m falling flat on my face into said ground at a speed my budget can’t handle…I think from now on I’ll start budgeting for car expenses instead of drawing from my general living budget, to make sure I’ll be able to be in a good position next time I have to rent for a trip or eventually get a new car. This forum certainly has taught me a lot about the unexpected expenses of owning a new-to-you used car.

You guys are so helpful!

PS – I really was wondering, before, whether a compression test is something I should ask to have done on any used car I might be considering…What needs to be included in a pre-buy checkup that my garage may not have included? Are there certain things I should ask for, other than the general “pretend you’re about to buy this car and check it as if it were going to be your own”? (After all, my mechanic may have a hard time imagining himself having only $3000 to spend on a car!)