Synthetic oil and valve guides - The definitive answer?

[msmith]

Alright this started life as the timing 101 post but kinda led to more questions. What I'm looking for here is kind of a definitive answer to this question so hopefully the title to this post gets the attention of enough people that have had this issue.

I changed my oil the other day and put in Castrol syntec 10w-30. I've used castrol syntec for years in my other vehicles and trust it. My car has 79k miles on and I've never had any issues making the switch from dino to synthetic on any of my other cars. I made the switch on my 95 lumina at 81k and it has never burned a drop of oil in its 216k lifetime.

Anyway, on to my point. I recently purchased my 79k DX and promptly went to work getting everything tuned. One thing I noticed was after and extended warm up period I will get noticeable blue smoke after I get in and head down the road. It burns off after a minute and doesnt come back until I do the same thing. Warm it up for an extended period of time. Now it may be smoking on the startup but its kinda difficult when the temp is -5 cause theres a lot of water vapor masking it I'm sure. Also, isnt 79k a little early for valve guides to be worn? Thats also why I suspect that it just may be the castrol syntec.

I know the history on this car and it was my mother-in-laws for the last 7 years of its life and I dont remember it ever smoking on startup. Would my switch to synthetic cause this? I suppose I could always switch back to dino oil and see what it does but I just flat out plan on running castrol syntec in it from here on out. If it is the synthetic causing it I guess I just plan on living with it and get used to it. One of the other things I have seen is a post saying that a catch-can ( Correct Name ? ) hooked up to the pcv or something like that will lessen this. If so what is that and how do you install it?

Sorry so long

Thanks
Mike

[redheddude222]

Full synthetic oil shouldn't smoke. If it's smoking on startup then goes away when you drive it's almost definitely the valve stem seals. The guides are probably fine. I got my old DX with 85k miles on it and it did the same thing. However, when I picked up my LX it had ~170k miles on it and didn't burn a drop. The B8 and the BP use the same seals, so it's probably just a case-by-case thing depending on the life of each car.

My DX came from a family that passed it on to their daughter in college, so that probably explains the smoking. I'm the 2nd official owner of my LX, and an old man drove it from day 1. When I got it with 170k on it it still had the stock clutch in it, and was driven mostly on the highway at steady speeds.

If your car was driven mainly in the city and not very far then the oil probably never fully warmed up. The thicker oil could possibly wear the seals out faster due to higher friction. Remember; just because the temp gauge shows that the coolant is warm, it doesn't mean the oil is warm too.

I'm taking an educated guess there. I may be wrong, and I'm sure more people on this board have more insight as well.

[msmith]

So whats the difference between the valve stem seals and the guides? I've never had the opportunity to tear into an engines valvetrain before.

[yunvmyegt]

the seals sit over the valve stem and the guide, the guide is just what the valve rides in

[ftjandra]

The guide is basically a cylinder, usually made of brass, that the valve rides in. You can't replace it yourself as it's pressed in. You would need to bring the head to a machine shop.

The seal on the other hand is made of rubber/viton and can be accessed by taking out the lifters/valve springs. As long as you keep the valves from dropping (compressed air, rope, etc.) you could replace those yourself.

--Ferdi

[msmith]

Are the seals a pain to replace? Any good writeups? I figure I'd need to get a spring compression tool anything other than that? Pretty adept mechanically but like I said, just never tore into a valvetrain before.

[msmith]

I guess Ishouldnt have been drinking when I responded. You kinda layed out what had to be done.

Thanks

[MD323]

castrol syntec has reported to cause smoking on otherwise good motors. I run mobil 1 with no smoking with higher miles.

[redheddude222]

When my car started smoking real bad before I replaced my blown turbo I ran Mobil 1 to stop the smoke. Worked great!

I'm 99% sure you have to take the head of to cpmpress the valve springs. If not I haven't figured out a way yet. Try putting a normal, non-synthetic oil like Rotella T in it and see if it still smokes as bad.

[MD323]

there are valve spring compressors that can be used on motors while assembled, but the BP springs are shrouded by the head, so i dont think you can make them work.

[redheddude222]

The ones that let you do it installed compress the spring upward, ours need to be compressed downward. That's the problem I ran into before I took the head off and made a spring compressor.

[msmith]

I think I'll just take the leap back to dino oil at the next oil change. Definitley seems to be the easiest of things to try. Cheapest too. I have a 77 vw bus that didnt mark its territory either until I started running synthetic in it. Just started picking up little leaks. Damn stuff will creep its way through the smallest openings.

Anyway, I'll keep you guys posted. Thanks for all the help!

Oh, one last thing. I'm really suprised that this didnt turn into a flame war about who's smarter because the use brand X oil. I was kinda worried about that. Most boards wouldve been at each others throats by the end of the first page.

[redheddude222]

I use synthetic in mine, and Rotella T 10w30 in the gf's Neon. The synthetic will tend to make leaks more pronounced also since it's so much thinner.