Can I do valve seals myself on '99 Avalon?



My Toyota Avalon smokes on startup - very intermittently and unpredictably - but it can look absolutely hideous when it chooses to do it (usually on the least desirable occasions). I got it used, but it wasn’t smoking until about 2 years after I got it. I’m pretty sure it needs valve seals and perhaps a sludge clean-out.

My local garage won’t do the job - they say they don’t have the tools. There’s no procedure for this in the Hanes manual.

I’m “funds limited” at the moment, in that I’ve got kids in college and kids in preschool and other obligations to carry.

Here’s my skill level: I can easily do brakes, water pumps, starters, alternators, etc. I have most ordinary tools. I have enough funds for parts and special tools, if necessary. I can read and follow instructions correctly (and you know that’s really, really rare!).

I’ve been putting this off for over a year, but I really want to get it done.

Is this a job I can do myself? If so, where do I find the instructions?




A professional mechanic told you that they CAN’T do the job and you admit that you’re skill level is not that good and you’re asking if you have the skills to do the job??? Am I missing something??

Before you tackle the valve seals…try to clean out the sludge. You want to do this slowly. I suggest you change your oil every 2k miles for the next 3-4 oil changes. Replace one quart of oil with one quart of Rislone when you do the oil change.


I’ve already done that. I’ve been through 3 oil changes at short intervals. The Rislone helps some, but the problem is still there.

When a professional mechanic says they don’t have the tools, does that really mean they don’t have the skills?


Listen to Mike. This is a complicated job, requiring major skills and specialized tools. If you’ve never rebuilt an engine (completely) then you don’t have the skills. I have, but they were older, simpler engines. I wouldn’t try it myself on a dual overhead cam v6 engine.

Instead, you might try one of the high miles oils, they have additive that might slightly swell the seals and (maybe) reduce the leakage. I’d do two things - start saving some money, and find a mechanic who can do this. Or live with it.


Live with the smoke until you can afford something better.


If your engine is badly sludged this may take many oil changes. It’s the ONLY way you can safely removed the sludge short of a complete tear-down. I have used this method and it works. Back in the 70’s when unleaded gas came out…it caused many engines to sludge due to the much higher engine temps. Many oils back there (Quaker State for one) could not handle the higher temps very well and sludged very easily. After switching to a better oil (Castrol for one) with one quart of Rislone cleaned the engine nicely.

The mechanic may have the tools and skills but still doesn’t want to tackle this job. Pretty sure on this engine you’ll have to remove the heads. It’s also transversly mounted which means it’s a pain in the *ss to work on. Have you ever done a timing belt on this engine??? You have to remove the belt in order to remove the heads…Along with the intake-manifold, fuel lines, exhaust manifolds. On a engine that’s EASY to work on it’ll take an experienced mechanic a couple of days to do this…For a novice…give it a full week.


You would have to decide if removal of the camshafts and valve springs is something you want to get into. As to specialized tools you would need a small spring compressor and a pair of specialty pliers to remove the seals. (my pliers are homemade from a pair of needlenose).
You would also need an air compressor to keep the valves in place while the spring is removed, or if a compressor is lacking a short length of small diameter rope can be used to wedge into the cylinder to accomplish the same thing.

As to instructions, use a Haynes manual up to the point where the cams are off and you’re ready to begin the seal process. From this point it’s probably a net search or post for advice here.
It’s a bit complicated but doable. Maybe this little blurb will help you decide if you want to wade into it or not. It’s not something you can do in a few hours. A competent DIYer should be able to knock this out in a couple of days without killing themselves.

Something else for consideration. Sometimes if sludge exists in the valve train area oil may pool around the valve guide bosses (where the valve seals are) and not drain back quickly into the crankcase. This can give the appearance of valve seals being much worse than they really are. Cleaning the drain holes, if sludged, may cure the problem.

Hope some of that helps in your decision.