No, but with the ABS systems you can damage the actuator, which decides how much force to send to each brake. Always break the bleeder, but if you
are afraid you will break that, loosen the bolt that holds the hose to the caliper.
And I just learned that too Wes
Yosemite
The crank case ventilation system works basically via a tube connected to the valve cover(s) to allow fumes from the crankcase, which is open to the space under the valve cover(s) via the oil return passages, to be drawn into the engine’s intake and burned with the fuel mix. Most, but not all, will have a check valve (one way valve) in the tube called a PCV (Positive Crankcase Ventilation) valve that allows free flow of the fumes into the engine, but severely restricts flow in the other direction to prevent backfires from igniting the volatile fumes from the crankcase. Any passage through that system goes into the intake manifold(s) and into the cylinders where it gets burned. It will not allow crud into the crankcase.
What will allow crud into the crankcase is coked, gumped up oil that gets that way from a failing seal in a turbocharger, which cooks oil (oil is circulated through the turbo bearing to lubricate and cool it), or poor maintenance, which allows oil to turn to gump as it washes heat and contaminates from the cylinder walls.
Another possible cause is the use of dino oil in engines that require synthetic.
The screen being referred to is the screen at the end of the oil “pickup tube”. The oil is drawn up from the pool in the oil pan by the pump via a “pickup tube” with a screen on the end of it, like a straw allows the drinking of a soda. The pickup screen is typically about 1/4" to 3/8" from the bottom of the pan. If, by poor maintenance, the oil pan is allowed to develop a layer of thick, clumpy oil at the bottom, it can plug up enough of the screen to prevent the engine from being able to develop sufficient pressure at idle. The only way to find out for sure, and the only way to correct this, is to drop the pan, remove the pickup tube assembly, and clean everything out.
By the way, if you poked crud out of the PCV valve grommet, you may want to remove the valve cover and see how bad the gump is, as well as doing the suggested pan removal.
no pcv on my jeep, it uses ccv instead, atleast that s what my book says. one or the other. only see ccv anyway. thanks tho.
gonna change sending unit first, since pressure prob only presents when hot and only started 2 days ago after vacuum repairs. and truck is running better, not worse
will go from there
oil isn t very dirty
ill get to valve cover gasket eventually
The 1990 Cherokee had a crankcase vent to the air filter housing plus an orifice vent(positive crankcase vent) to the throttle body. The orifice is a small hard plastic tube in a grommet at the rear of the valve cover.
I have what my book calls a fresh airsupply tube from air filter housing to top front of valve cover and calls that tube to grommet in the rear top of valve cover to the throttle body the CCV and says the jeep has either ccv or pcv not both. the tube to grommet has vacuum as it says it should.
I m not saying I m right, just reporting what it says.
I have Cherokee Laredo if that matters…
maybe I m reading it wrong but it has a picture too that calls it ccv
this Haynes manual is not good so I may be totally wrong and I appreciate all input
my better half did over fill oil a couple weeks ago, but at least she checked it.
I m trying to teach her to atleast maintain fluids so in case I croak she ll stand a chance of keeping a vehicle running
well my fingers are starting to loosen up, better go back to the jeep now.
did I mention how much I appreciate ALL input?
its funny, I just received my junior grease monkey badge.
seems accurate, and yes, that is grease on my jeans…, and hands and elbows and…
A rose by any other name, as they say. The small tube orifice vent is connected to manifold vacuum and that means it is a positive vent due to its negative pressure I guess.
CCV = closed crankcase ventilation.
there are four different systems used for just the in line 6. they are all piped differently and some, like my son s have pcv , mine has ccv. I have the all the diagrams here. there are even two types of ccv system… mine the air out comes from back and goes to intake manifold. the other comes out from front and goes to throttle body.
the ones with pcv are more complicated
well I ve screwed everything up trying to get this hub assembly out to change the universal. I quit
Come on Wes…you got to get really greasy before you give up for the day.
When my buddie and I work at his shop, he always teases me. He could have a Timing belt job to do while I replace a dome light.
I’d somehow get a couple of smudges of grease on my pants, and he’d walk away with just a little grease under one fingernail.
I don’t think I purposely wipe my hands on my pants, but I must have a habit of doing it without thinking.
Yosemite
FUBAR
guys, I think I screwed up bad.
I drove the the rotor partially off the hub assembly instead of getting the whole assembly to come out of the steering knuckle bore.
I didn t want to get into the bearings I just wanted to take the assembly out so I could get to the universal
can I drive it back in with an impact gun and the the hub nut or will that push something out the back of rotor like a bearing?
or can I drive it back in with a hammer and large socket?
and if I can get it back in how can I get the hub assembly out of the knuckle bore? I tried to tap it out like it showed and got nowhere so I thought driving the rotor off must be it. wrong!
can I put the bolts back thru the knuckle and partially thread them into the hub assembly again and hit the bolt heads to start it out of the bore?
I am not doing very well on this project and its really getting to me
I haven’t read through all the posts on this, but if you’re reading the RPM right, 350 at idle is way low–I’m not surprised that your oil pressure reads low if you’re reading the tachometer correctly.
that’s in drive with foot on brake, after fixing vacuum probs, cleaning ccv, and other things.
read my last post, any thoughts? the oil pressure is not my main prob now
hey guys. thanks for all the input on my oil pressure. I m not too worried since it is fine mostly and that only happened after we d been driving for an hour and had just been stopped in traffic for awhile and was fine after cooling and re start. and the fact that its running better than ever.
I m gonna start a new thread with my current serious prob because I m in a jam and need help.
we have no safe vehicle til I fix it
thanks, wes
I agree with Oblivion. At 350rpm idle you’re not going to build any oil pressure. The whole thread has gotten too lengthy for me to go through, but that would be the reason for the lost oil pressure.
Oil pressure is developed by the pump trying to push more oil through the spaces between the wear surfaces than they’ll allow to readily pass. At 350rpm, your oil pump is not trying to push enough oil through the spaces to create pressure. The small amount of oil being flowed is simply passing by the bearings unpressurized.
The pressurized fluid actually suspends the wear surfaces on the crankshaft and the connecting rods from the bearings. Unpressurized fluid will provide some lubrication to some areas (it will fail to disperse properly, so there may be totally unlubricated areas), but it is not sufficient to prevent bearing wear and/or damage.
I recommend that you consider the lost oil pressure at idle to be serious enough to address. Look at those things that affect the idle speed. Again, I haven’t gone through the whole thread, so they may have already been discussed, but once you’re through with the rolling issues, you need to consider the idle speed.
Please understand that I’m not trying to scare you. I only wrote this post because I care.