Baja Uber Alles |
Sun Aug 24, 2008 7:53 pm |
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My '86 westy has 125K original miles (engine has never been rebuilt), and the oil light/buzzer just started to intermittently come on around 2000 RPM - never at idle, never at higer RPMs.
I can make the light/buzzer go away by blipping the throttle, or giving it more RPM for a sustained period of time, or letting off the gas. Sometimes the light/buzzer comes back on after doing this, sometimes it doesn't. No apparent ryme or reason.
I've read the oil pressure threads in the sticky, so it looks like I'll need to get an oil pressure gauge and run some tests, but based on my symptoms, is this a bad sign that the rod bearings are starting to let go? |
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glutamodo |
Tue Aug 26, 2008 2:18 am |
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There's going to be some wear, of course, but I'm going to guess that your lower end is still in not too bad of shape. However I have read that one article about how the rods themselves like to distort on 2.1 liter engines over time... ( http://www.bostonengine.com/articles/low-oil-pressure.htm )
What weight of oil do you have in the engine right now?
I'd look carefully at what the oil looks like when you change it next.
Do the oil pressure test - if it's decent it could just be a weak oil switch, or it's just at that RPM it's a hair off on pressure... but fine otherwise, which may be the case as you describe it. You could always put an oil-switch #2 from a disel engine in there, which has a higher threshold before it kicks the buzzer on.
-Andy |
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tencentlife |
Tue Aug 26, 2008 8:20 am |
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You mean a lower threshhold, I think.
You should do the OP tests, as it's always wise to assume first that a warning function is doing its job and warning you of an actual problem brewing. Make sure the engine is plenty hot when you do the tests, and it's best if possible to look at OP out on the road under load instead of revving in the driveway. Always try to simulate real conditions when testing. If you have a friend who can drive while you ride in the back to watch the gauge you can see what happens for real.
But I would think the bottom end isn't too bad off at that mileage, and the behavior sounds like a switch that's getting a little too sensitive in a particular OP range, where it closes again when OP varies. But do the tests, and if they're OK then put in a fresh high-OP switch, the one on the rear of the block under the water pump pulley. The switches can't be expected to work forever, after all. I would just do them both since you'll have the low switch out for the test anyway. |
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Baja Uber Alles |
Tue Aug 26, 2008 8:35 am |
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glutamodo wrote:
What weight of oil do you have in the engine right now?
I'd look carefully at what the oil looks like when you change it next.
I have always run castrol 20W50. When the problem first arose, I changed the oil, it was black, but no visible metallic particles. (I checked my records, it was only 1500 miles since the last oil change, but 10 months had elapsed! :oops: )
I changed the oil (4.5qts castrol 20W50 and a new Mann filter) and took it for a spin. Absolutely fine for about 10 minutes, but then the light/buzzer came back on with a vengeance (probably about the time the oil reached its operating temperature) This time, the light/buzzer would not go out if I revved it. :( I didn't have much time to mess with it last night, but I checked the wire going to the hi speed switch, and it looks good.
I will definitely do the oil pressure test. I need to buy a gauge, can anyone recommend one (preferably that has metric threads on the adapter)? Anyone know off hand what size thread the hole is for the oil pressure switch? |
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tencentlife |
Tue Aug 26, 2008 9:11 am |
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It's M10x1.0 thread. It happens that a 1/8"MPT plumbing fitting is a near-perfect match to the M10 thread, so you can make your own gauge from common plumbing fittings. The MPT thread is tapered, unlike the metric, so it will run in and seal by the thread taper. Just don't overtorque it. Despite what some nervous nellies will say, it will not screw up the threads in the case so long as you're moderate with the torque.
A 0-60psi water pressure gauge from a home supply can be used. It will probably be off by 1 or 2 pounds, but the error tends to be pretty consistent throughout the range. You don't need such fine resolution for this test anyway, within 5psi will tell you what you need to know. Some of the FLAPS carry a ready-made gauge with various fittings. They will have very short hoses, so you might be better off making your own as you could attach a hose long enough to have it above the engine and be able to watch it while a friend drives.
With oil hot, you should see at least 10psi per 1000rpm, maxing out at about 4k, and allowing that it will be lower than that rule at idle. Hot is 180F plus, but 220-230 is a more realistic OT for the engine when it's hot, and that extra 40-50deg. is what makes the difference between 40psi at 4000rpm and 25psi. It takes a solid 15 minutes of running to get oil to 180F even in warm weather, so don't rush your test. Once again, try to simulate the conditions under which you typically get the warning, as in length of time running, load, water temp indication, etc. |
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Baja Uber Alles |
Tue Aug 26, 2008 9:34 am |
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tencentlife wrote: It's M10x1.0 thread. ...
Great info, thanks! |
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otiswesty |
Tue Aug 26, 2008 12:16 pm |
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The question then becomes, if the oil pressure sender is fine and the oil presure is running low, what is there that can be done?
I recently had this problem on the road at the beginning of a family vacation. 2000 RPM, going up a grade, oil light and buzzer comes on first time ever. 179K miles. Freaked me out. Oil level OK, still running pretty well too. I was at altitude ranging from 4000 to 8400 ft on oversized tires. The wirning reoccurred a couple of times at that idle, and went away with downshifting. It was hot at the end of the trip >100 F, AC running, and I limped home 2 weeks later with a slightly leaking pass side headgasket. My #3 had no compression, and the motor is getting rebuilt now. Could there have been an intervention that would have prolonged the engine life? I figured with close to 180K, I would drive it until it boxed as it most likely needed the bottom end gone through.
I'm also going back to close to stock tire size except for 4wheeling, for better gearing. |
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tencentlife |
Tue Aug 26, 2008 6:47 pm |
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otiswesty wrote: The question then becomes, if the oil pressure sender is fine and the oil presure is running low, what is there that can be done?
I guess that question is rhetorical.
Quote: Oil level OK, still running pretty well too.
Without a gauge or working warning system, the first sign of too low OP is the rod knock followed shortly thereafter by engine seizure. They run just perfectly right up until the instant they grenade.
Good thing you're getting it rebuilt. Hope they do the rods right. |
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bucko |
Wed Aug 27, 2008 4:24 am |
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"Without a gauge or working warning system, the first sign of too low OP is the rod knock followed shortly thereafter by engine seizure. They run just perfectly right up until the instant they grenade. "
I may print this and place it on the garage wall! That quote made me chuckle. How true though. |
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Alan Brase |
Wed Aug 27, 2008 8:52 am |
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bucko wrote: "Without a gauge or working warning system, the first sign of too low OP is the rod knock followed shortly thereafter by engine seizure. They run just perfectly right up until the instant they grenade. "
I may print this and place it on the garage wall! That quote made me chuckle. How true though.
Print it into a label and sell them on theSamba classifieds! Put on upper left corner of windshield.
Al |
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Alan Brase |
Wed Aug 27, 2008 9:04 am |
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Is there a sticky on this? There should be!
1. Make sure you use a good German oil filter. Fram is not German and not good.
2. Never overfill the oil level. It will be much better 1/2 quart low. Less windage and lower oil temps.
3. There is thicker oil. Actually Mobil 1 and a few other genuine synthetics are quite good. Multi vis oil NEVER stays as thick as the high number. Genuine 40 straight weight Shell Rotella is what I have been using for the last 50k miles since my 91 started buzzing. Except for 3 or 4 months when it's cold.
4. It's not the sensor 90% of the time, your engine is getting a bit worn. Generally, the buzzer will come on at 2000, then go off at 2100 or some slightly higher speed.
5. It's not the sensor.
6. Sorry, it's not the sensor.
Last year, I bought an 87 Westy for $300 that had a really nice jumper wire to ground out the HP sensor. Unfortunately, the harness was nearly cut in half by the rod as it exited the case at high velocity.
Pretty poignant! I guess that sensor was okay after all.
Al |
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tencentlife |
Wed Aug 27, 2008 9:35 am |
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That's just classic, isn't it? |
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Baja Uber Alles |
Wed Aug 27, 2008 9:50 am |
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I found an oil pressure gauge at the FLATS (Friendly Local Automotive Tool Store) - (Daly City Tool Mart in Daly City, CA) that has a long hose, and several adapters, including M10x1.0, it was only $30, perfect! Now I just need to find some time to do the OP test... |
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bucko |
Wed Aug 27, 2008 10:52 am |
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Baja Uber Alles wrote: I found an oil pressure gauge at the FLATS (Friendly Local Automotive Tool Store) - (Daly City Tool Mart in Daly City, CA) that has a long hose, and several adapters, including M10x1.0, it was only $30, perfect! Now I just need to find some time to do the OP test...
DON"T USE ANY OIL PRESSURE GAUGE THAT USES A HOSE (oil fluid) TO PROVIDE OIL PRESSURE TO A GUAGE!!!!
The distance from the engine to the front (or even rear) is just asking for yet another oil leak to drain oil out.
Get an oil pressure guage that uses a gound type sensor to indicate oil pressure. One wire to the B+, the sensor is a varying ground, and a third wire to your parking lights. |
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Baja Uber Alles |
Wed Aug 27, 2008 11:24 am |
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bucko wrote:
DON"T USE ANY OIL PRESSURE GAUGE THAT USES A HOSE (oil fluid) TO PROVIDE OIL PRESSURE TO A GUAGE!!!!
This is just a diagnostic gauge that will be hooked up temporarily, not one that will be permanently mounted in the dash. |
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bucko |
Thu Aug 28, 2008 3:58 am |
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Baja Uber Alles wrote: bucko wrote:
DON"T USE ANY OIL PRESSURE GAUGE THAT USES A HOSE (oil fluid) TO PROVIDE OIL PRESSURE TO A GUAGE!!!!
This is just a diagnostic gauge that will be hooked up temporarily, not one that will be permanently mounted in the dash.
Why not just install an oil pressure guage permanantly? As TENCENTLIFE pointed out, it's your best reference to see your oil pressure at all engine RPM ranges. If you go through the effort of installing one for this diagnostic troubleshooting event, you might as well make it permanent, just don't use one with an oil tube to the front.
It is most likely the best gauge you can have in a Vanagon. The air cooled guys like the engine temp gauges too. Us water cooled guys don't need that one. |
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tencentlife |
Thu Aug 28, 2008 6:44 am |
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Yeah, install a gauge and then you can sweat over it every time you drive.
bucko, whattaya wanna, ruin his life? |
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Baja Uber Alles |
Sat Sep 06, 2008 3:12 pm |
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OK, hooked up the oil gauge, here are the results:
With the engine cold, I started it up; at idle (about 990 RPM) the OP was 60 PSI at first, then as the temperature rose to operating temperature, it gradually decreased to 10 PSI.
Then I drove it around for about a half hour, it was about 90 degrees outside, and the engine was well up to operating temperature (fan would come on at long stoplights) As I drove it around, the OP seemed to always be around 10 PSI at idle.
on level ground:
2000 RPM = 25 PSI
3000 RPM = 32-35 PSI
going up a steep hill (under load)
2000 RPM = 20 PSI
3000 RPM = 30 PSI
Didn't get a chance to take detailed readings from 3000-4000, but it seemed to increase to about 40 PSI around 4000 RPM.
I guess these numbers are about OK? I already got new replacement high and low switches, so I'm going to go ahead and install those.
Given my OP numbers, would it be a good idea to start running straight 40W oil instead of 20W50? (I'm in a temperate climate, SF bay area) |
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tencentlife |
Sat Sep 06, 2008 4:11 pm |
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Those numbers are pretty good for its age. Time for a new high switch. Just do them both, and see how it goes. Going to higher weight oils is a last resort, in my opinion, and straight 40 is pretty extreme. The Castrol GTX 20w50, if that's what you're using, ain't what it used to be and the VI improvers are known to break down very quickly, in about 1k miles. It's been a mainstay for many years, I've been using it for thirty, but I wouldn't use it anymore for general longterm service. For best operation of the hydro lifters and cold-start lubrication, I lean toward a lighter baseweight so long as it maintains good OP when hot. I've been running Rotella 5w40 synth for awhile now, with external oil cooling. 15w50 Mobil 1 holds up really well in these engines, but it's gone SM so no longer has the good anti-scuff protection our older engines require. Mobil1 makes a 20w50 Extended Protection that I believe still has an SL rating. Overall it seems like your OP is good enough that you don't need to bandaid it by raising the oil weight; just replace the high switch. |
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tschroeder0 |
Sat Sep 06, 2008 6:55 pm |
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Just a thought on something you briefly mentioned..."at long lights the fan would come on"
This makes me wonder about tenncent's comment about that extra few degrees making the difference.
After having gone over my whole cooling system; hoses, radiator, correct bleeding etc... my fan does not come on and my gauge at its hottest will max out just below 3/4. This is going up a mountain canyon at 8-9000+ft on a 90+ degree day and/or sitting at a stoplight on the same day.
Just wonder if you're running hot? Todd |
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