Dipstick

[89Joe]

I dont know if this is a problem or anything but my dipstick keeps popping out. Not completely but just partially. I cant think of why it does this, and I havnt noticed any change in anything. The dipstick just kinda comes out, not sure from pressure or what. So just tell me if this means anything or if its just nothing, and not to worry about it.

-Joe

 

[Yellow 13]

Mine comes out all the way. no real problems if it does. You can get some silicone and put a bit on if your worried. just make sure non falls down into the oil pan.

 

[supramacist]

It comes out a bit in our 91. I don't dig on it either. I would also like to know why this happens.

 

[Allan_MA70]

check your PCV system, or maybe your rings are fryed?

 

[89Joe]

How would I know if my rings are fried? I have noticed sometimes a small puff of burnt oil will come out of the exhaust, but this isnt very often.

 

[1TuffSupra]

compression and leak down tests

 

[jetjock]

Mine comes out all the way. no real problems if it does. You can get some silicone and put a bit on if your worried. just make sure non falls down into the oil pan.

:biglaugh: Now *that's* funny. I couldn't make that kind of stuff up if I tried

 

[supramacist]

leak down tests????
Is this where I measure how much oil my engine is leaking. j/k

 

[Fuzz420]

my pops up just slightly, on the old motor it used to pop out real far, this time it around it stays in there pretty good

 

[Yellow 13]

:biglaugh: Now *that's* funny. I couldn't make that kind of stuff up if I tried

I meant I can pull it out, it doesnt pop out when im driving or anything lol.

 

[Bishop92t]

You can actually still purchase the dip stick from Toyota and it's surprisingly cheap. I got a new one for around $10.

 

[supramacist]

Please don't make me edit anymore of your posts! <IJ>

 

[jetjock]

If your dipstick is popping out you need to find out why. Sounds like your cranckcase isn't being ventilated. Put a condom or rubber glove over the dipstick tube and see if it inflates. If so forcing the dipstick to remain in will just blow out seals elsewhere. Check the PCV system first. If it's working you have excessive blowby that must be corrected. The dipstick must remain in for other reasons ie; an open dipstick tube is a source of pirate air. Your ecu doesn't like such vacuum leaks.

 

[supramacist]

my dipstick has only done this 2 times that I can remember. Could it have something to do with driving the car hard??? I check my oil almost daily bec ause I have a leak. I am taking the car to toyota on this coming monday to have diagnostics ran on it. Hopefully this will also tel me the compretion ratio. I am trying to do everything I can without restoring, the car. It's in good shape. Annyhow two times that I can think of this has happened. I have put just barely 3000 miles on it. Your'e the shit jetlock and I trust and value your opinion. I was wondering if someone here can break the term "blowby" down to mr. potato head style for I have herd the term but have no idea as to what it really means. thank you

 

[jetjock]

Blowby is just what it says: Leakage of combustion gases past the rings or valves. In the case of rings these gases go into the crankcase where, if they're not removed, they'll pressurize the crankcase and lead to seals blowing out. Usually the dipstick is the first thing to vent this pressure and is a sign something is amiss.

Look behind the alternator. See that big hose connecting the crankcase and left valve cover near the oil filler cap? That's where the gases in the crankcase are supposed to be let out. They're supposed to go into the valve cover and then from the valve cover into the throttle body. That's the Positive Crankcase Ventilation system. It's job is to scavenge blowby. And yes, the harder you run the engine the more blowby you'll have if your rings are leaking because the pressure in the cylinders goes up as the engine makes more power.

Does the engine burn oil? Blowby works both ways. If the combustion gases can get into the crankcase the oil in the cranckcase can get into the cylinders and be burned. That won't do your valves and cat conveter any good so yeah, you need to do a compression test to see if your rings are worn enough to let too much gas "blow by" them. And check to see if the PCV system is working. The hoses could be kinked or the hole in the throttle body gunked up. All that said, if your disptick is blowing out only when you get on the engine and it doesn't happen often it's simply a sign bad things are starting to happen. Your engine is talking to you. Listen.

As for pirate air, other than the small chamber in your N/A AFM used to adjust idle mixture, all the air entering the engine must be measured. Any air that enters the engine that isn't measured is air the ecu doesn't know about. That's bad. If the PCV system is sucking on the crankcase and the dipstick is removed air will flow into the disptick tube, up through that hose behind the alternator, through the valve covers and throttle body into the intake manifold.

That air is unmetered. It's "pirate" air that got into the engine without the ecu measuring it. Think of it as a vacuum leak because that's what it is. You already know vacuum leaks aren't good to have. The mixture will become leaner because of this extra air but since the ecu doesn't "know" about it, it can't correct for it.

Fix the oil leak and do a compression test. You don't have to restore the car but neither should you ignore any problems. They never get better you know, only worse. Good compression is the heart of any engine and without it you might as well use the car for a flower bed.

 

[89Joe]

Good info! But anyway, how do I go about doing a compression test? I've never done one, and have no idea about how I would go about it. As for the PCV system, what can I check to make sure that isnt that problem? Which hoses are part of the system, and what would be required to check it?

-Joe

 

[BosoMKII]

To do a compression test you need a compression tester. They are not too expensive. Its like a big tire pressure gauge that screws into your sparkplug hole in the cyl head. Pull the fuel pump fuse, take out all the spark plugs, open the throttle and and crank the starter until the gauge stops reading any higher. That is your compressoin, check it against the specs in the FSM.

Edit, PVC system: http://www.cygnusx1.net/supra/library/TSRM/ec/EC_05.html

Your engine is much happier with this system. The little filters for your valvecovers look cool but thats it. They don't hurt anything, but really the crankcase likes vacuum best. Just make sure the hoses are not clogged and you should be good to go.

 

[89Joe]

Would I be taking off the TB?

 

[BosoMKII]

Yeah, I don't think you can get to all the spark plugs with out taking the TB off. I have not tried though, and I still don't know the 7M that well. Maybe someone else has a trick to get it done.

 

[jetjock]

Hmmm....this is all basic stuff. I suggest you read the manual. If you don't have one get one. A real one, not some crappy Haynes or Chilton. The manual will also tell you about the PCV system. Anyway, for compression testing you can either do a direct compression test or a leak down test. Direct testing is the most common in the automotive world.

First, go buy either kind of compression tester. Direct testers are the most widely available. Warm the engine up and remove the spark plugs. Remove the EFI fuse to disable fuel and spark. Pulling the fuel pump fuse isn't enough because you'll still have spark and without the plugs connected you run the risk of damaging the ignition system. Make sure the battery is charged and in good condition. Warming the engine will charge the battery and will also expand the rings. You can do a cold compression test but hot is better and the right way.

Screw the tester into one cylinder at a time. Hold the throttle plate wide open and crank the engine until the tester needle peaks. Write the value down and go on to the next cylinder. Compare the values to the manual. If a cylinder is low pour a teaspoon or two of oil in the plug hole and repeat. If the pressure comes up the rings are bad. If not it's valve related. This is why I prefer leakdown testing to direct testing, it's easier to find out what's wrong. The downside is having to mess with the crank to set each cylinder to TDC.

If the pressures are above spec you likely have combustion deposits on the piston crown that'll need cleaning but that's an entirely different subject.

The PCV system on an N/A consists of (I think, I don't own one) the same setup as the turbo except for the boost hose back to the accordian. The crankcase is scavenged through the aforementioned hose behind the alternator on the left valve cover. The valve covers are then scavenged through by connecting them together and then to the throttle body. I'm sure some N/A owner will correct me if I'm wrong.

Btw, you might wish to go easy on that quote button. It just clutters up the forum when dealing with long posts like mine