burning some oil

88*mr2 · 07-12-2009, 07:26 PM

my 88 has 139k on it and i have to put some oil in it every 3 months or so when the pressure drops below 1/4 on the stock guage at idle speed...wat could i do to diagnose the problem??

any help?

dirocyn · 07-14-2009, 03:05 PM

YOu could just change your oil every 3 months, that will solve it. If you're less than a quart low after 3 months, you're not doing too bad.y. Stock oil pressure gauges are notoriously imprecise, you might consider getting a better quality guage that's calibrated so you can tell what psi it's running.

Burning oil and oil pressure are not directly related. Oil burns if it leaks into the cylinders, usually past the valve guides or the rings. Oil pressure will drop if the oil level drops, if the screen on the oil pump pickup gets gunked up, if the oil pump leaks, or if the main bearings get worn.

88*mr2 · 07-14-2009, 05:30 PM

well i know its not leaking i have checked so my guage is bad or its burining any guage good?

dirocyn · 07-15-2009, 12:29 PM

Quote:

Originally Posted by 88*mr2

well i know its not leaking i have checked so my guage is bad or its burining any guage good?

I'm not sure I understand your question. If you see bluish smoke coming from the tailpipe, it's burning oil. If you have zero leaks (park with the back half of the car on top of a refrigerator box, let it idle 20 mins and then sit over night to make sure) but you are still more than 1/2 quart low after 3 months, you're burning some oil. Burning oil means ineffective rings, leaky valve seats, or you're somehow sucking oil up through your pcv (I had a Ford Escort do this, badly). With burning oil, you change the PCV valve first, then compression test dry vs. wet to check the rings. If neither of those reveals the issue, go ahead and replace the valve seals.

Oil pressure going low is a completely separate issue, unless you burn so much oil that the oil pump pickup is sucking air (meaning you're 2-3 quarts low). My oil pressure gauge reads just over 1/2 when it's cold, right at 1/2 at 3,000 rpm and hot, and just under 1/4 at idle when it's hot. Which is a little on the low side, (to be expected with 225k miles) so I run 20w50 and check my oil every time I fill the gas tank.

Tjzsin4given · 07-15-2009, 02:10 PM

What should the compression test come out to be on a 3sgte???
i know the ratio should be 8.8:1 but ima noob so i know nothing about the test! :-(

dirocyn · 07-15-2009, 02:21 PM

Quote:

Originally Posted by Tjzsin4given

What should the compression test come out to be on a 3sgte???
i know the ratio should be 8.8:1 but ima noob so i know nothing about the test! :-(

Most folks on this thread have 4age or 4agze, there might be a better place to ask. I did a quick google search, the number I'm finding for the 3sgte is 178 psi. But what's important is the level of variation between the cylinders. If there's more than a few psi difference, that's a problem.

toyotaspeed90 · 07-15-2009, 09:47 PM

Quote:

Originally Posted by Tjzsin4given

What should the compression test come out to be on a 3sgte???
i know the ratio should be 8.8:1 but ima noob so i know nothing about the test! :-(

you'll get a lot of answers as to what it should be.... mainly because there are many ways to do it.

pull your efi fuse, pull your spark plugs, and when cranking count the number of revolutions and match per cylinder. As you crank it over, keep the TB at WOT.

you should probably be in the ballpark of 140-160psi, I would guess..... how high the numbers show isn't as important as the variance between cylinders... you should see no more than a 10% variance (which can be quite the variance.... if one reads 160psi and another 144.... something is wrong)

to the OP: 4age's tend to get a bit oil consumy (not really a word, but whatever).... the 3 culprits are: small leaks, piston rings, valve stem seals....

#1 is easy.... inspect the motor closely for leaks... if you don't see drips on the ground that doesn't mean you're not leaking oil

#2 can't really do much except maybe add ATF prior to an oil change and run it for 15 minutes.... rings will either unstick or continue to have blowby.... other option here is a rebuild

#3 unless you have the special tools required to do an in-car valve job, it's gonna be a PITA... the head design doesn't allow for useful valve tools

I would say just run 10w40 and check it monthly or so until you decide to do a swap.

Tjzsin4given · 07-16-2009, 01:42 PM

wow thanks you guys. This isn't even my thread but you gave me some usefl info!

07-12-2009, 07:26 PM	#1 (permalink)
88mr2 mk1 Join Date: Jul 2009 Location: iOWA Posts: 68 Thanks: 12 Thanked 1 Time in 1 Post iTrader Rating: (0/0%* )	burning some oil my 88 has 139k on it and i have to put some oil in it every 3 months or so when the pressure drops below 1/4 on the stock guage at idle speed...wat could i do to diagnose the problem?? any help? Last edited by 88mr2; 07-14-2009 at 12:37 AM.*

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07-14-2009, 03:05 PM	#2 (permalink)
dirocyn Cage Fighter Join Date: Mar 2009 Posts: 133 Thanks: 6 Thanked 12 Times in 12 Posts iTrader Rating: (0/0% )	YOu could just change your oil every 3 months, that will solve it. If you're less than a quart low after 3 months, you're not doing too bad.y. Stock oil pressure gauges are notoriously imprecise, you might consider getting a better quality guage that's calibrated so you can tell what psi it's running. Burning oil and oil pressure are not directly related. Oil burns if it leaks into the cylinders, usually past the valve guides or the rings. Oil pressure will drop if the oil level drops, if the screen on the oil pump pickup gets gunked up, if the oil pump leaks, or if the main bearings get worn.

07-14-2009, 05:30 PM	#3 (permalink)
88mr2 mk1 Join Date: Jul 2009 Location: iOWA Posts: 68 Thanks: 12 Thanked 1 Time in 1 Post iTrader Rating: (0/0%* )	well i know its not leaking i have checked so my guage is bad or its burining any guage good?

07-15-2009, 02:10 PM	#5 (permalink)
Tjzsin4given Found an MR2 Join Date: Apr 2009 Location: Brooklyn, NY Posts: 129 Thanks: 21 Thanked 0 Times in 0 Posts iTrader Rating: (0/0% )	What should the compression test come out to be on a 3sgte??? i know the ratio should be 8.8:1 but ima noob so i know nothing about the test! :-(

07-16-2009, 01:42 PM	#8 (permalink)
Tjzsin4given Found an MR2 Join Date: Apr 2009 Location: Brooklyn, NY Posts: 129 Thanks: 21 Thanked 0 Times in 0 Posts iTrader Rating: (0/0% )	wow thanks you guys. This isn't even my thread but you gave me some usefl info!