I've posted a few times regarding what appears to be worn valve seals on my engine, which results in a fairly brief (but very noticeable) cloud of blue smoke when starting cold after a long trip the day before. I've tried the measures suggested to me (heavier weight oil, add a can of Restore), but neither suggestion has diminished the problem. I found it interesting that no one else wrote in saying they had the same isssue, leading me to believe that I may have the only 2000 XK8 on the planet with this unique problem.


A second possibility recently occured to me. When I purchased the car, the engine was pretty sludged up (only 58,000 miles). After flushing it several times, it now appears to be very clean, but I'm wondering if the oil return galleries in the head may still be somewhat clogged, leading to the valve guides being overloaded with oil that is draining too slowly (okay, I'm clutching at straws). Because I drive less than 5,000 miles/year, my car is exempt from emissions testing in PA, so this is not something that prevents me from driving it except embarrasment. Given an estimated price in excess of $ 2,000 to replace the valve seals, a more economical solution is what I need. With the exception of this one problem, the runs great.


Any thoughts?

 

Whether it's the valve guides or the seals, the problem isn't going away and there is no cure other than replacement.

Replacing the seals can be done without removing the heads, I think, but it's still a lot of work. Some one wrote a while back that you can push rope into the spark plug holes and use the piston to hold the valves closed while removing the keepers. Not a fun project.

 

I agree that there probably isn't a real alternative to the problem other than replacement. You can replace the seals without removing the head, but it's a tedious process. I used to work on Jaguars back in the late 70's, and still have a tool that you hit with a hammer which pulls out the valve keepers gives you access to the seals. Then you put the keepers into an attachment on the tool, and use a hammer to put them back in place. It only works if you can hold the valve rigidly in place. We used to pressurize the cylinder with air to keep the valves closed. The process works, but I'd be loathe to take on that project with 32 valves to deal with!

 

Just a stab in the dark but have you considered a bad PCV valve. Engine pressure builds up and you say it is after an extended drive the day before. Maybe your engine isn't venting properly, plugged part load breather, plugged fulled load breather.

It will probably throw a code but try just pulling the dip stick up about an inch and see what happens with the smoke.

I really think unless the engine was overheated the seals wouldn't just fail.

 

This is why a used car should always be checked out prior to purchase by a trusted/skilled technician

However, what you describe does sound like valve seals. There is no magic oil and/or cleaner that would possibly restore those seals. There is no way to replace the valve seals without removing all the camshafts though. $2K+ sounds about right though. Since you are embarrassed about driving your car in it's current state, I'd suggest that you should ask yourself these questions.... Do you love this car enough to shell out $2200 and if so, would you drive it more often if you weren't embarrassed by it? If you answered yes to either of these, I'd just go ahead and have it repaired. If you said no, then sell the car to someone who would take care of it.

I don't mean any disrespect, I'm just trying to help you make a smart decision.

 

No offense taken. As I mentioned previously, this is about the only problem I've ever had with this car. Yes, I do love this it, and the smoke doesn't keep me from driving it. More of an annoyance than anything else. I'd probably feel a bit better if I knew that this is a known trouble spot on these engines. So far, no one has posted about the same/similar problem.

 

What oil range were you using and what did you change it to and how long with the new oil?

Gus
www.jagrepair.com

 

Max......We are both old dogs, when it comes to this type of stuff. This problem could be related to valve seals, but with the rubber compounds out today, I have seen very few failures, unless your XK8 is really a Chrysler Sebring in disguise. What does the smoke smell like.....fuel....coolant? Do you leave a small cloud of oil smoke, when leaving a stop light? Does the oil smoke appear, when you down shift, and accel rapidly? If the answers to these questions are no, chances are the problem is elsewhere. Check where there is venting to the throttle body, and intake. If all this causes you to lose sleep, we could probably have a party in your garage, for a week, and I would undercut the other guy by a couple 2, 3 hundred dollars. Don't get too wild, but I am leaning towards a system, that retains pressure after the engine is shut down, and leaking into the intake side somehow........Stand back, and see what theories you can come up with, without me taking your money, and sleeping on your sofa.......I live for this kind of stuff.......Be cool......Mike

 

I have a 98 XK8 with 77,000 miles and 05 XKR with 47,000 miles and both will do this, on occasion. There does not seem to be any reliable away to predict the little oil cloud, not length of time left, nor following a long or short trip, just every now and then on starting a small oil cloud is generated. I've used various weights of oil, dynasuar and synthetic, with no difference.
In the end is it a big deal? Lots of engines burn a little oil, some of the best engines ever built burned a little oil, ever watch a RR Merlin start for example?
If my engine burns a little oil like a Merlin, well it's in good company...
Regards,

 

Thanks to all. To answer some of the questions you raised:


Oils - I've used full synthetics, 5w-30 and 10w-40 with no noticeable difference in the extent of blue smoke on startup. Also added a can of Restore to no affect. Current oil, Mobil1 10w-40 has been in for about 1,000 miles. Considering trying Valvoline MaxLife 10w-40 synthetic blend at the next oil change to see if using a part-dino oil has any affect. Oil use is approximately a quart every 500 miles, give or take.


Full and Part-Load Orifices - Cleaned both. Is there a PCV valve on this engine? Didn't see one.


Smoke - Blue, every time when starting cold after a long trip the day before. Short trips, where you re-start fairly soon after running the engine, produce little, if any, smoke. Also, no smoke starting off from a light, or letting it back down in gear, then accelerating. No noticeable leaks or drips.


This is not something I lose sleep over, just something that has me a bit puzzled. Once I've eliminated any other possibilities, and it only be valve seals, period, then I'm just going to suck it up and live with it (Mike; thanks for the offer of the garage party, and agreeing to relieve me of any excess money I have, but knowing how battered your body is. my couch would be a deal-breaker for you!).


Max

 

Just to let you know I occasionally get a small puff of smoke too at start up, maybe notice it about once a month. No smoke at any other time, 133,000 miles on the clock. This is way down at the bottom of my to do list.

 

Ok it sounds like you are trying the right things. I was going to suggest adding 10w30 synthetic and drive it for a few hundred miles and see what takes place. I personally would not go up to 10w40.

Edit. This is a good link about oil. bobistheoilguy.com

Gus
www.jagrepair.com

 

Using a quart per 500 miles seems like quite a lot to me. That would make me think about rings.

 

a little blue smoke isn't a concern but as above a QT / 500 miles means it's seeping into the cylinders and burning off.. perhaps a compression check, it's easy and could answer some questions. Of course qt of oil isn't expensive compared to service, but it's stressing the other components of the Fuel/Air system such as cats/o2s which modify intake parameters.

 

There's also the possibility of a valve cover leak; a common problem on our cars. It wouldn't necessarily be obvious when driving (and my sense of smell isn't that good), so something else to check. I've also considered the possibility of bad rings, but that's not something I'm willing to address at the moment. Committed to driving it until something blows up (I'm a fatalist), or until I go senile; whichever comes first. You can buy a lot of oil for what the alternative courses of action would cost. As previously mentioned, I'm going to go to a part-synthetic, high-mileage oil to see if that helps at all.
Many thanks to all that responded. Unless you own one of these cars, it's had to understand the degree of passion they inspire.