Sick of Smoky startup - can I change valve seals with heads ON THE CAR?

Ozz

Senior Member
Greetings,
My '03 300A MM just passed 105k miles and instead of smoking on start up a half dozen times a month, it smokes like it's on fire every time it sits for over an hour.
As the norm, it only smokes for a few seconds (and I think only on the left side) but it's kind of embarrassing and I'd like to see if there's anything I can do WITHOUT REMOVING THE HEADS.

My guess is that I can remove the cams, etc and, if it's anything like my 5.0, I can hold the valves closed with air pressure while I carefully remove the springs and faulty seals.

I'll do a compression and leak down test prior to attacking the seals but assuming they are both fine...

Anybody ever tried this or am I just dreaming about a cheap solution that doesn't exist?
 
I put a Metco Valve Breather on and it went away all together. Let me just say; I was a HEAVY smoker for over two years before. Now it's gone. It's been about a month and still good. $50 on Ebay, just make sure it's for a Marauder and not a Crown Vic.
 
I put a Metco Valve Breather on and it went away all together. Let me just say; I was a HEAVY smoker for over two years before. Now it's gone. It's been about a month and still good. $50 on Ebay, just make sure it's for a Marauder and not a Crown Vic.

I looked at it and I can see how it might help if you have excess blow by and smoke while driving but I don't see how this would help with oil that runs down the valve stem when the engine is shut off...?

Did your engine just smoke at start up or all the time?
 
Last edited:
If your PCV system is getting old and plugged up installing the breather above will help reduce pressures positive and negative to reduce oil being pushed were it should not be.
 
I changed my PCV a few thousand miles ago (part of my 100k service) so unless I have a lot of blow by, I don't think that's my problem.
I will check to see if I have oil in the line but assuming I do not, I think this is one of the typical 300A's with a bad left side head (seals &/or guides).

Thanks!
 
I put a Metco Valve Breather on and it went away all together. Let me just say; I was a HEAVY smoker for over two years before. Now it's gone. It's been about a month and still good. $50 on Ebay, just make sure it's for a Marauder and not a Crown Vic.

Really! I have to try this. I have the intermittent smoke cloud on startup after sitting a while (1hr+) post trilogy install. You could have made my exhaust into dry ice and put it into your drink before the install.

Putting that together with a comment about the PVC instruction being wrong on the trilogy instructions on another thread that may be my problem. Where do I connect the breather? In liu of the PVC or somewhere else?

Ozz perhaps your problem is not engine internals cause mine were spic and span before the install and the problem started day 2 with no performance problems associated.

Thanks!
 
Last edited:
I'm tempted to try an oil separator in the PCV line. It would make sense if there is some oil in the line that it drains into the intake while the car sits. A separator would help but I'd have to remember to empty it...

I'll check the line tonight and see if it's wet.

I'm not a fan of putting a breather in the valve cover because any air that passes in (or out) is unmetered and can throw off the A/F ratio as the actual amout of air in the intake is more (less) than the MAF has measured.
 
Even better check out this part's review

http://www.steeda.com/store/steeda-oil-separators-for-ford-mustang.html

"Does the job and looks great.

I installed a Steeda Oil Separator on my 2003 Mustang Cobra after installing a Whipple supercharger. When I took the stock supercharger the heat exchanger was coated in oil. It took 8 cans of brake parts cleaner to get it looking right again.

Seeing the oil that the Separator is collecting is great assurance that it is working. And the kit fits exactly and looks like it was installed at the factory. Having the collector clear (vs. Stainless Steel) allows you to see it is working and also lets you know when it needs emptied.

You won't find a better oil separator at this or any price point."

This exact setup sounds very familiar.
 
Yea, I'm just shaking down my Paxton 1220 SL install on my '91 GT and I picked up a cheapo oil separator from Harbor Freight. I have only done a few short pulls but so far no oil in the bowl.
The Paxton kit has you put a fuel filter in the line just above the nipple on the oil fill and then further down the line I put the oil separator for added insurance. The filter is positioned so that it will drain back into the oil filler but I'll have to manually drain the separator bowl.

If I have oil in my MM's pcv line I will certainly be spending a few $ on a separator to see if it helps get rid of the smoke.

Thanks.
 
I looked at it and I can see how it might help if you have excess blow by and smoke while driving but I don't see how this would help with oil that runs down the valve stem when the engine is shut off...?

Did your engine just smoke at start up or all the time?

Start up, and it was A LOT! I assume that once the excess oil in my intake burned out, the pressure relief from the breather stopped the oil from re-entering the system as blow-by.

That was my hope when I installed it, and I think that is EXACTLY what happened.

It smoked every startup very bad until I installed the breather. That is the only change I made.
 
The past 2 oil changes i have used valvoline max life synthetic blend with 3\4 a bottle of bardahl no smoke plus stop leak.

It has cut my startup smoking down by at least 75% to the point that it doesn't bother me at all, no more clouds, just a puff here and there. Oil consumption is also down to only a quart added between 5k mile changes. I don't add anymore no smoke between changes.

Flame suit on, i know people think the no smoke is 'snake oil that will eat my motor', not my experience, runs great.

:beer:
 
Sorry to be a dunce, but where would stick this breather? In the PVC hole? Do you replace a stock breather with it?

I always understood PVC to be a vacuum balancing mechanism. Makes sense to me that the greater the difference in airflow (like positive displacement) the more gunk could be swept up in that airflow. I don't mind the balance being resolved within the sealed system, just the gunk that goes with it. PVC oil separator could fix that.

What do you think?
 
My guess is that I can remove the cams, etc and, if it's anything like my 5.0, I can hold the valves closed with air pressure while I carefully remove the springs and faulty seals.

Anybody ever tried this or am I just dreaming about a cheap solution that doesn't exist?
IIRC the problem was with the guides, not the seals.
 
Sorry to be a dunce, but where would stick this breather? In the PVC hole? Do you replace a stock breather with it?

I always understood PVC to be a vacuum balancing mechanism. Makes sense to me that the greater the difference in airflow (like positive displacement) the more gunk could be swept up in that airflow. I don't mind the balance being resolved within the sealed system, just the gunk that goes with it. PVC oil separator could fix that.

What do you think?

Replace the stock oil cap with the breather.
 
I checked my PCV tube and there did seem to be some oil in there. I may try putting an oil seperator in line before I put on a breather (don't want to allow unmetered air into the system).

Thanks for all the replies.
 
Back
Top