Smokes when put in reverse.

[voyager92]

Hello:
I am running a 3.0 a670 in 92 Voyager 167,000 mi. It is stock n/a for now. It has a wierd smoking problem. It is fine most of the time. It smokes when I put it into reverse to back into my driveway or to turn around. Sometimes it is a large cloud and takes a little while to clear up. It has the usual leaky valve covers. The motor runs well and is tight otherwise. It sometimes does it after a quick goose of the throttle too. When it is very hot out sometimes it will start puffing some when in traffic. I expect it to be a little tired. It is so strange the way it smokes almost every time I back into my driveway. I had heard there was an issue with the valve covers holding oil and the pcv sucking it in. Is that on the 92 or different year? By the way my driveway is downhill but it does on the level also.

[shadow88]

The valve guides are a well known wear item on the 3L engine and likely require a machine shop to replace them. I really can't see how the gear selector has anything to do with the smoke.

[black86glhs]

The guides and the PCV system causes the same issues. The valve covers have baffles in the top and over time they get clogged up with sludge. It doesn't matter how well taken care of, it happens to most of them. I take the VCs off and drill a couple extra drain holes near the factory ones in the baffles. Then you need to clean out the sludge. You need to replace the VC gaskets anyway. I try this fix first when I get one that does this. It is much cheaper than pulling the heads and if it doesn't fix it, you not out much $$$$$.

[RoadWarrior222]

Check the PCV hoses, usually when it just suddenly starts while in traffic when the engine is hot, it's the PCV hose sucking flat, gets soft when warm.

---------- Post added at 03:57 PM ---------- Previous post was at 03:55 PM ----------

Oh btw, these motors really, really like Castrol and Pennzoil high mileage oil. 10W30. cuts smoking leaking and consumption, gas mileage might go up a tad.

[voyager92]

Yeah its really strange how it seems to happen when shifted into reverse. Thanks for the tip about the baffles. I was thinking of trying that. By the way, do the valve covers lift right off? It looks like there is not much room to get them past the intake runners. The manual just says remove the cover, sounds to easy. It always seems like what should be easy jobs end up PITA.

[RoadWarrior222]

I've got half a thought that due to fluid pressure being higher in reverse, the motor sucks harder, more vacuum... which again makes me think PCV hose sucking flat.


My baffles, I just backflushed with brake cleaner before an oil change... and avoiding use of any of the bandaids and workarounds 3.0ers use for oil consumption*, which all translate to top end sludge, they seem to stay clear now, with the use of High Mileage pennzoil or castrol (I've tried other brands, stick to those two)

(*Typically, use 20W50, or use cheap supermarket oil because it eats so much, or use gloop additives like lucas stabilizer or miracle in a can stop leak... don't do any of these)

[black86glhs]

Yes, they pretty much lift right off. Follow RW22's advice on the hoses, also. When they get gummy, they will pull closed easily.

[voyager92]

Thanks guys I'll change the gaskets, oil, and pcv lines this weekend after payday.

[c2xejk]

If the PCV fixes don't work, likely the guides. You can either throw a pair of newer junkyard heads on or have somebody like me replace the guides and port the heads...

Ed Kelly - www.kmperformance.com

[RoadWarrior222]

92 and up shouldn't theoretically be dropping the guides, but valve stems seals are likely...

[c2xejk]

92 and up shouldn't theoretically be dropping the guides, but valve stems seals are likely...

Agreed, I did wonder if the heads had been replaced before or if it was an early vehicle...

[TurboV6Van]

I bandaged my old 3.0 smoking issue with 20-50 Mobil 1 synthetic oil... synthetic doesn't seem to smoke like conventional oil does. Most likely the guides are bad

[RoadWarrior222]

IMO with 20W50 and other thick gloops (Lucas, bardahls etc) they reduce top end lube, due to being harder to shove up there, resulting in the thin layers of stuff that does get up there burning on the heads. Starting is hard in cold weather and lifters don't pump up very quick. Also lose gas mileage.

[TurboV6Van]

IMO with 20W50 and other thick gloops (Lucas, bardahls etc) they reduce top end lube, due to being harder to shove up there, resulting in the thin layers of stuff that does get up there burning on the heads. Starting is hard in cold weather and lifters don't pump up very quick. Also lose gas mileage.

Could be a good theory... all I know is it stopped smoking. My uncle told me about synthetic oils not smoking after he used it in a Dodge Ram van with bad rings. It still consumed the oil, but didn't smoke. I've used thick conventional oil and it still smoked.

[Ondonti]

Could be a good theory... all I know is it stopped smoking. My uncle told me about synthetic oils not smoking after he used it in a Dodge Ram van with bad rings. It still consumed the oil, but didn't smoke. I've used thick conventional oil and it still smoked.

Found the same thing with synthetic. Buy cheap Walmart synthetic.

I think the top end and heavy oil burning is all opinion. My built motor had lucas and 20-50 in it constantly for 3 years to help prevent oil burning and plug fouling, and the top of the heads are he same as the day installed. The only burned oil is in one of the heads that was already like that and I did not get cleaned off. It burned a quart every 100 miles or less.

[voyager92]

I've been using 15w 40 and 20w 50 for awhile. It reduced oil usage. I changed the pcv line, so far no smoke. I going to change the gaskets this week. I'll get to check out the sludge situation then.

[RoadWarrior222]

Maybe regular RPM excursions help flush the top end better, all I know was it built up in mine over 5 years following the gloop plan and I thought I was gonna lose it to sludge. At that time it was doing mostly city and traffic duty.

[voyager92]

Its doing better with the new pcv line; but it smoked a little again today when I backed into the driveway. I tried to use 5w-30 in it when I first got the van and it used it incredibly fast. Of course the valve cover bolts were about ready to fall out. ;-) Even after I tightend them up it still seemed to last better with 20w-50. The lifters do tick some on cold starts in cold weather so I will try to go back to at least 10w-30 after I change gaskets and clean it out.

[shelbymonster]

my 3.0 spirit have bad valves seals , put some rottella 15w40 and never smoked again , even my pacifica have some bad valve seals and stopped with 15w40

[black86glhs]

The 15w40 is a good compromise. I would use that before going 10w30.