When I hammer on the throttle bore (or close to) I leave a trail of heavy white smoke behind me. Doesn't happen if I don't go full bore at all. I also have a slow leak from my front oil seal. Related? Maybe more oil comes out and hits the exhaust or is it worse and I have a major problem? Thanks for any advice you have.
White smoke under heavy acceleration
- Thread starter spinaldex
- Start date
- Location
- MilkyWay Galaxy
Heavy acceleration increases engine vacuum, and can suck in more oil into the combustion chamber is the valve stem oil seals are bad. The easy to inspect and easy to replace, just pull the valve cover off, and check the spark plugs to look for cylinders with bad valve seal, they will be black and oily.
- Location
- MilkyWay Galaxy
Check the CCV ventilation orifice for plugging, it can plug and cause the crank case to build up pressure pushing oil out the seal.
Is this a 2000 rig? Specs on the jeep please?
Is this a 2000 rig? Specs on the jeep please?
Yes, it's a 2000 XJ with the 4.0.
I'm ok at stuff like gears, lockers, etc but I have very little experience with motors. Most I've done is replace a water pump, rebuild a carb, and basic tune-up stuff on the various rigs I've had. I might ask my buddy to help check things ...
So, pull the valve cover off and then check my Haynes for what valve stem oil seals are? and then, also pull all the spark plugs and see if any have excessive residue on them which might indicate which cylinder has a bad seal? They are brand new plugs (month old) so that should be really easy to tell. Might do that tomorrow night first.
By CCV I'm assuming you mean crank case ventilation, so do you mean the two PCV valves sticking out of the top of the valve cover? I replaced the front one, but the rear one hasn't been replaced yet and both the seal, hose and valve itself look in bad shape. I was thinking about checking them out. Interestingly enough, this issue didn't exist when i bought the rig a few months ago. It started after I did a bunch of stuff to the rig, so its quite possible the new PCV valve could be bad and building up pressure now?
I'm ok at stuff like gears, lockers, etc but I have very little experience with motors. Most I've done is replace a water pump, rebuild a carb, and basic tune-up stuff on the various rigs I've had. I might ask my buddy to help check things ...
So, pull the valve cover off and then check my Haynes for what valve stem oil seals are? and then, also pull all the spark plugs and see if any have excessive residue on them which might indicate which cylinder has a bad seal? They are brand new plugs (month old) so that should be really easy to tell. Might do that tomorrow night first.
By CCV I'm assuming you mean crank case ventilation, so do you mean the two PCV valves sticking out of the top of the valve cover? I replaced the front one, but the rear one hasn't been replaced yet and both the seal, hose and valve itself look in bad shape. I was thinking about checking them out. Interestingly enough, this issue didn't exist when i bought the rig a few months ago. It started after I did a bunch of stuff to the rig, so its quite possible the new PCV valve could be bad and building up pressure now?
WB9YZU
NAXJA Forum User
- Location
- Madison, WI
White smoke is often water vapor.
A '00?
Check your oil for water.
A '00?
Check your oil for water.
One other possibility. I did a fluid change on the transmission. If, I say .. overfilled it .. and the smoke was only coming out when I was hammering on it, couldn't that also come frmo it?
Also, what's the best way to tell the difference between oil and oily water? The fluids were changed just a few weeks ago and I have less than 200 miles on an oil change, tranny fluid and radiator flush I did myself.
Thanks.
Also, what's the best way to tell the difference between oil and oily water? The fluids were changed just a few weeks ago and I have less than 200 miles on an oil change, tranny fluid and radiator flush I did myself.
Thanks.
The thing I find weird is it did not have this problem 2 months ago when I bought it. I've only driven 500 miles on it in that time. Isn't it possible something I did to the vehicle could have introduced the problem and not be a blown headgasket or cracked head? I've changed fluids, oil pan and transmission pan seals, new PCV valve, O2 sensors, spark plugs. GAH. I'm freaking out because doing a headgasket is a huge job.
Oil and water seperate. Drain it and inspect pan. As far as trans causing white smoke. Most older vehicles will but afaik there is not a vacuum modulator on the jeeps
joe_peters
NAXJA Forum User
- Location
- Grants Pass, OryGun
1. Black smoke--rich condition.
2. Blue smoke--rings and/or valve guides/seals.
3. White smoke--water/coolant.
At least those are the rules I was taught in the Fifties.
1. Take it out, hammer it, then pull the plugs and check their condition--any of them look like they have been steam cleaned?
2. Look under the oil fill cap--latte?
3. Check the dipstick--latte?
4. Run a compression test, and if a cylinder is low run a leak down test to determine where the problem is.
5. As you have one of the infamous years, take a look through the valve cover at the head between cylinders 3 and 4--any coolant there?
2. Blue smoke--rings and/or valve guides/seals.
3. White smoke--water/coolant.
At least those are the rules I was taught in the Fifties.
1. Take it out, hammer it, then pull the plugs and check their condition--any of them look like they have been steam cleaned?
2. Look under the oil fill cap--latte?
3. Check the dipstick--latte?
4. Run a compression test, and if a cylinder is low run a leak down test to determine where the problem is.
5. As you have one of the infamous years, take a look through the valve cover at the head between cylinders 3 and 4--any coolant there?
- Location
- MilkyWay Galaxy
I had a 76 Dodge charger that blew white smoke like yours (but mine was at heavy throttle on the freeway, doing about 80), that was leaking transmission fluid burning as it hit the exhaust pipe.
Since yours is a WOT only, during heavy vacuum, that is why I suggested intake valve seals.
I have seen white smoke from the transmission fluid burning (described above) and extreme rich diesel fuel smoke, beyond the black smoke level, way WAY rich when my SD22 lost the pneumatic diaphragm and went to a super rich fuel feed.
I think I recall seeing white smoke decades ago from heavy oil burners, 1970s, like a Chevy truck I had in 1974 that burned oil like crazy.
I could see a slug of oil at WOT killing the spark and then raw fuel partially burned in the exhaust causing white smoke, I think?
But water-coolant must also be ruled out, just not sure why water-coolant would only show up at WOT? Unless the high vacuum draws it in from somewhere?
Since yours is a WOT only, during heavy vacuum, that is why I suggested intake valve seals.
I have seen white smoke from the transmission fluid burning (described above) and extreme rich diesel fuel smoke, beyond the black smoke level, way WAY rich when my SD22 lost the pneumatic diaphragm and went to a super rich fuel feed.
I think I recall seeing white smoke decades ago from heavy oil burners, 1970s, like a Chevy truck I had in 1974 that burned oil like crazy.
I could see a slug of oil at WOT killing the spark and then raw fuel partially burned in the exhaust causing white smoke, I think?
But water-coolant must also be ruled out, just not sure why water-coolant would only show up at WOT? Unless the high vacuum draws it in from somewhere?
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I'm going to take a stab at some of this tonight when I get home. The issue only happens when I'm under full throttle. I've had it happen twice, once going up a hill, full bore, at 60mph, and another time on the freeway when i hit the fast lane and passed someone doing 75. It never happens other than that. If I hammer on the throttle in my driveway and keep it pegged at 5k for 2 minutes, no smoke whatsoever.
As far as color, I have a hard time telling. It's not black, but it could be white or white/blue. The reason I can't tell is that the window's are tinted a dark purple tint and if the smoke was blue, it would still show whitish through the shaded windows. And since I can't replicate it in my driveway, I have zero clue.
There's a ton of oil splattered down the engine on the driver's side so I'm still thinking it could be an issue where there's a clog or a leak from the CCV/PCV hoses and as pressure builds up maybe its dumping it on to the exhaust. A good indicator there is that the cab fills with the smoke too so its not just coming out of the exhaust. If it was only out of the exhaust I likely couldnt smell it at 75mph. It also doesn't smell sweet, it just smells like burning oil.
/shrug
I will just start with checking fluids, pulling plugs, tracing down the CCV/PCV hoses, and seeing what I come up with. I don't have a compression testing kit but can rent one next week when I get paid and go from there.
Thanks for all the help folks!
As far as color, I have a hard time telling. It's not black, but it could be white or white/blue. The reason I can't tell is that the window's are tinted a dark purple tint and if the smoke was blue, it would still show whitish through the shaded windows. And since I can't replicate it in my driveway, I have zero clue.
There's a ton of oil splattered down the engine on the driver's side so I'm still thinking it could be an issue where there's a clog or a leak from the CCV/PCV hoses and as pressure builds up maybe its dumping it on to the exhaust. A good indicator there is that the cab fills with the smoke too so its not just coming out of the exhaust. If it was only out of the exhaust I likely couldnt smell it at 75mph. It also doesn't smell sweet, it just smells like burning oil.
/shrug
I will just start with checking fluids, pulling plugs, tracing down the CCV/PCV hoses, and seeing what I come up with. I don't have a compression testing kit but can rent one next week when I get paid and go from there.
Thanks for all the help folks!
- Location
- MilkyWay Galaxy
There is no PCV valve on XJs, 4.0s. Just a complex network of CCV lines that depend heavily on the rear line and a tiny orifice in that rear line (not sure where it is on a 2000). If that orifice clogs up some or completely it can result in pressure build up in the crankcase that forces oil out the engine seals and even into the air filter. Start there!!!! Check the CCV layout against the sticker on the firewall!!!! See if something is not connected up right.
The front CCV(the one that goes to the airbox) was one of the elbows with the small hole in it. Same with the back one. I cleaned out the back one and then drilled a large hole through the front one making it a straight through. Then, i let the rig run for 30 minutes and then pegged it at 4500 RPMs for 2 minutes with no smoke. Then I drove it and hammered on it and no smoke again. I also checked the oil level and its over full but the color looks normal, so that could be compounding the issue it's building oil pressure too much. I noticed that when I hammer on it, the oil pressure gauge is at 3/4 and I think its suppose to be closer to the middle when that happens, so I think I need to drain some oil now.
notamos
NAXJA Forum User
- Location
- Fort Collins, CO
Was it "overfull" when you changed your oil? The overfull oil could actually be coolant mixed w/ oil. Look at your coolant, any oil in it? I'd drain the oil completely and let it sit - watching for separation. If it does = blown head gasket/cracked head. Very common on these years. 0331 head.
But, hope for the best.
But, hope for the best.
birchlakeXJ
NAXJA Forum User
- Location
- Melrose, MN
Keep a VERY close eye on your coolant reservoir. With the 00-01, checking it at least weekly should become a habit with the infamous 0331 cylinder head.
- Location
- MilkyWay Galaxy
Did the later years have a second orifice in the front tube, or did some one use a rear elbow with the orifice up front my mistake?
The drop tubes inside the valve covers of the older VCs had a bad habit of letting one suck oil from the top of the valve train right into the air filter and intake manifold. Two contributing factors were non-OEM CCV lines or clogged lines, and oil on the top side collecting and draining back to the sump too slow. Not sure if they are on the later year VCs?
Sounds like you fixed it, at least for now. Most of us cut the bottom inch of the tubes inside the valve covers, or drill vent holes up higher in the side of those tubes.
The drop tubes inside the valve covers of the older VCs had a bad habit of letting one suck oil from the top of the valve train right into the air filter and intake manifold. Two contributing factors were non-OEM CCV lines or clogged lines, and oil on the top side collecting and draining back to the sump too slow. Not sure if they are on the later year VCs?
Sounds like you fixed it, at least for now. Most of us cut the bottom inch of the tubes inside the valve covers, or drill vent holes up higher in the side of those tubes.
There are two on the valve cover, and both had the closed end with the pin hole which is wrong. Front needs to be straight through, back needs to be the pin hole. Since I fixed that, ZERO issues. Put a few hundred miles on it so far, all the way up and down the mountain a couple times. This was definitely not a seal issue, for now. Thanks guys.
- Location
- MilkyWay Galaxy
Then it is essentially the same as the CCV set up on the Renix and OBD-I years. So it might be safe to assume that a totally oil clogged air filter would do about the same thing. Interesting. Looks like it builds pressure in the crankcase, and throws oil into the intake via the valve cover port/tube assy inside the valve cover. Most of us that know of the issues have cut one inch off the bottom of the tubes and or added a by pass breather holein the upper side of the two tubes, it is a metal tube inside, under the valve cover. Also confirms my suspicions that many excessive engine seal leaks are there one minute, gone the next, from excess pressure in the crankcase!!!! But it requires a defective CCV system!!!
Thanks for confirming this, and glad to hear it was not the usual suspect, a blown head or head gasket.
Thanks for confirming this, and glad to hear it was not the usual suspect, a blown head or head gasket.
- Location
- MilkyWay Galaxy
This is one of the tubes under the valve cover that feeds the top side CCV lines!
http://www.cherokeeforum.com/attach...rong-w-my-xj-please-help-image-2192664585.jpg
The rear one is the one that is most likely to suck oil into the intake, the front one throws oil all over the brand new air intake filters
http://www.cherokeeforum.com/attach...rong-w-my-xj-please-help-image-2192664585.jpg
The rear one is the one that is most likely to suck oil into the intake, the front one throws oil all over the brand new air intake filters
Devilfrog
NAXJA Forum User
- Location
- Duncan, BC
Can't see the pic, but I just went through my VC, chopped an inch off both tubes, and found both splash plates under one tube so put them back properly (one stainless splash plate per tube. The down tubes already had a 1/2 hole drilled in the top portion of the tube.
My VC is a '93 vintage one. Just mentioning for the splash plates thing really, mine was pulled with the '93 head and when I did the head swap I did nothing to the VC.
But the '00 VC is an all stamped and welded assembly, so much harder to modify accordingly, but, I guess it's all moot anyway, even more so since the issue is solved.
My VC is a '93 vintage one. Just mentioning for the splash plates thing really, mine was pulled with the '93 head and when I did the head swap I did nothing to the VC.
But the '00 VC is an all stamped and welded assembly, so much harder to modify accordingly, but, I guess it's all moot anyway, even more so since the issue is solved.
