I've read that synthetic oils have a tendency to squeeze past gaps that conventional oil doesn't. I have an ongoing problem with worn valve seals that apparently allow oil into the combustion chambers when sitting after a trip. The result is a 10-second cloud of blue smoke when re-starting the engine cold. Not a serious engine problem, but it is a bit embarrassing when there are other people standing near by. Would the valve seal seepage be reduced by going back to a conventional oil and changing it and the filter more frequently, and what are the long-term ramifications, if any, if I do?

 

Have you performed a compression test or leak test lately? Your description is more indicative of worn or broken piston rings.

Exhaust smoke on deceleration would indicate worn valve seals or valve guides.

How many kilometres/miles are on the engine?

 

Synthetic oil is just fine in the car however; if you are using 5w30 you need to change it to 10w30 and see if the problem is cleared. Give that a try first before you start pulling things apart.

 

Yes, valve seals will cause smoke at cold start. Exhaust smoke after deceleration is a symptom of worn rings.

 

I believe you have it backwards.

 

The stories of synthetics causing leaks are by and large exaggerated. Since there is no requirement by Jag to use these oils and no real-world benefits (flame suit on ) I'd switch back to conventional oil of the correct viscosity and see if this helps with the problem.

 

Thanks to all that responded. The ONLY time the car smokes is starting up cold, and usually only after a trip at highway speeds. I've tried backing it down in gear and then accelerating and there's no smoke at all, and the car runs perfectly in every other respect except that it uses a quart of oil every 500 miles. Obviously connected to the smoking problem. I've already switched to 10w-30, and it doesn't seem to help. The car only has 60,000 miles on it; way too little for the valve seals to normally be worn out (unless there was something in its past I'm not aware of). The problem is more annoying than anything else. But then again, you can buy one heck of a lot of oil for what it would cost to replace the seals.

 

I wonder if valve seals go hard and lose their suppleness through age rather than mileage?

 

FWIW I have had valve seals cause smoke on start up and hard acceleration on a prior car (Porsche). I was told they failed primarily from heat and age, not so much a function of mileage.

 

1980s Ford CVH engines were well-known for this. I had an Escort that started smoking on startup after 8 years but with only 20K miles on the clock.

 

While the OP root cause is unknown he should get the compression check done to eliminate or find out what's what. While you can continue to add 1 qt of oil / month it doesn't just evaporate, it's getting burned in combustion (probably) which isn't good for the motor or cats. I understand a engine job is big $ and wouldn't want to have to pay for one myself but knowing what's wrong is some peace of mind over not knowing, the fix can come later.

 

Thanks for the suggestion. I totally understand what you are saying about getting a compression test, and I don't have my head in the sand regarding the condition of the engine. If the car didn't run like a gazelle in Sport Mode, had blue smoke, oily film on the rear bumper and/or other symptoms that would indicate a possible imminent rebuild, I would probably spring for the compression and leak-down cylinder tests. Being somewhat of a fatalist, however, I'll just continue driving it until there is a compelling reason to tear it down (or I run out of money for oil). In the interim, if I discover anything regarding its high oil consumption, I'll be sure to post it.

 

You could try a can of Restore and see what takes place. Restore works well with cylinder wash but not sure with valve seals.

Gus
www.jagrepair.com

 

The 'HIGH MILEAGE' engine oils are 'supposed' to help soften engine seals.
You might try it.

bob gauff

 

Do these high-mileage oils actually soften engine seals, or is it just another marketing gimmick?

 

Is it magic, is it a scam, or is it true? You decide.

 

After watching the video, all I want to know is when did Bob and Doug MacKenzie move from the Great White North to the Aloha State??

 

And NO, I don't have any association with or intent to promote this particular product. I have no idea at all if it works or not, I merely meant to bring up the option of additives that claim to stop oil burning, since I had not seen that mentioned before.

Here, you can go right to the horse's mouth and ask them in the comments section. Click on the "Watch on You Tube" at the bottom right of the video.



Derek Abbring 4 months ago
It's now the end of December, 2014 (almost 11 months) and the car still doesn't smoke. I also haven't had to add any extra oil to the motor either.
Reply · 1

Derek Abbring 2 months ago (edited)
A lot of people have been asking how it works to stop the smoke. REHAB4’s amine salt of a dialkyl dithiophosphoric acid forms a long-lasting coating that fills in grooves in the cylinders to reduce gap clearance and it eliminated the oil blow-by this sebring was experiencing. It's now Feb 2015, car still doesn't smoke & its going up for sale.
Reply · 2

ijosef 3 weeks ago
My bruised and battered '98 Prizm (rebadged Corolla) has gradually started using more and more oil now that it's got almost 300k miles. The whole drive train is original and has never had any work other than routine maintenance (plugs, wires, valve cover gasket, PCV, etc), so I'm thinking the motor is just tired and worn. Would any of these products help me get a little more life out of the old gal before she sees the junkyard?

 

This thread is really interesting, and the claims and counter-claims are likely to go on forever; the YouTube videos notwithstanding. A couple of things bother me:

1. The large oil companies spend millions of dollars testing and developing additives that will help them market their product. They have access to more information and resources than any of us will ever have. So now I'm to believe that a (very) small company, with nowhere near these resources, has found a proprietary chemical formula that has somehow eluded the big guys (either that, or the oil companies want people to keep on putting oil in their worn out cars).

2. Now suppose one of these companies did find the Holy Grail of oil additives, and started to market it under their own name. How long do you think it would take before they were gobbled up by one of the major players, and the product re-packaged under that company's name?

But we all continue to live in hope.

 

What I suspect is the case is that the quality oil that the major manufacturers produce is perfectly fine for an engine that is in good shape. I think that as an engine ages and starts to suffer from a good deal of wear (don't we all?) that there are some additives that cost more to produce than regular oil does that can help out an engine in some situations. No additive is going to repair a burned valve or a cracked ring, or some other actual damage, but they just might help out a problem due to wear.

FWIW, here is what is purportedly an objective test of Restore. Decide for yourself.