Date: Sat, 8 Aug 2009 21:05:29 -0700
Reply-To: Scott Daniel - Turbovans <scottdaniel@TURBOVANS.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Scott Daniel - Turbovans <scottdaniel@TURBOVANS.COM>
Subject: Re: temperature-oil pressure (rather long)
Content-Type: text/plain; format=flowed; charset="UTF-8"; reply-type=response
ok, some thoughts.
first, regardless of where the temp needle is on the guage, what really
matters is the actual temp of the engine and the coolant.
I would guess it's running about 195 F when it's very good and hot.
that is not a problem by itself, that's good actually .
I don't think you'll gain much by trying to improve very hot temperature
control by flushing.
If you think getting it to run at say 190 instead of 195 when it's hottern'
hell...........then replace the radiator, unless it's new.
oil pressure is a function of ...
rpm, temp of course, oil viscosity .....and most importantly bearing
clearance.
2.1's are known for having oil pressure issues after a while - usually with
many miles on the engine, and when running hot at high rpm.
We are always reading about the oil buzzer going off,
from the high pressure part of the oil warning circuit saying' I'm not happy
!'
stock, there are tw oil pressure switches, a low pressure one, and a high
pressure one, and they are tied into the tach ......so it's 'smart' ......
called the DOPS - dynamic oil pressure system .........it's very common for
the high rpm/high temp oil pruessure to be marginal - enough to make the
buzzer go off .....in high temp high rpm situations. I've read that the rod
bolts stretch ........and that's why 2.1's do this.
1.9's evidently don't. I do think they have a better, and less stressed
bottom end than 2.1's.
about changing a oil pump to get oil pressure that has 'gone away' or
deteriorated.
Sure ......oil pumps wear some ......but they run in oil.
I 'don't believe' in replacing oil pumps on used engines.
that is not to say that I disbeleive that people have fixed vanagon engines
that way for an oil pressure problem ......
it's just that it's a 'patch' aproach.
if .......the removed oil pump was installed sloppily ........good that that
was found.
The fact that it was chagned previously .......
if it was ......hello !
that would be a big red flag to me......since as far as I'm concerned, it's
never 'normal' to replace an oil pump on a waterboxer engine,
especially TWICE by 146,000 miles I think you said.
that makes me think this engine has had a history of exactly what you are
expereincing.
the real repair ? .....
most likely, restore crankshaft bearing oil cleaance to spec.
For most people, that means 'rebuilt engine' .....
though it is something that can be repaired, while saving the not-worn-out
parts of the engine.,
generally, a waterboxer engine is never bored out, as it has replacealbe
piston liners. You just put in a new set of matched pistons, wrist pins, and
cylinder barrels.
so stock bore size would be normal.
usually you don't bore out cylinder liners, unless it's to make a hot rod
special or something like that.
that's what I think - it's not the coolant temp, though that might be a tad
higher than optimum under stresfull conditions..
oil viscosity isn't gong to help much,
oh ........also ..........oil seems to 'go off' pretty quickly to me,
especially with high heat.
You put new oil......its seems 'thick' .................by 2,000 miles
.........it can be like dirty water, in some engines, in some conditions.
the more worn the engine btw, the more it contaminates its own oil just by
running.
and it's not the oil pump, although that you now have slowly rising cold oil
temp that is strange.
I had a 53 chevy with a factory mechanical oil press gague that did that
...........took a few minutes of running and driving ...for the needle to
come up.
what is normal.......
is that as soon as you fire it up , it should do what it used to do
.........max out cold rpm oil pressure at say 2,000 rpm pretty much right
away.
there is an oil pressure relief valve that limits upper cold oil pressue
I wonder if that was messed with.
a few things people may not understand .......
a cooler themostat doesn't make a car run cooler, once it's above that
t-stat's rated temp. If the van is running at 195 F in hot condtions...
it doesn't know if there is a 160 t-stat in there, or a 180 or etc.
same thing for oil pressure relief valves and the spring associated with it.
You can raise the upper limit of cold oil pressure, but it won't make oil
pressure where there isnt' any. If it's going to run at 10 psi at a hot
idle...........the oil pressure relief valve is completely out of the
picture.
Just in case anyone had a unusally ideas about these two.
I like and trust mechaical oil pressure gagues a bit more than electrical
ones. There is the disadvantage of an oil line that can break or crack, and
there is some delay in the reading on a long thin plastic or copper line. I
like electrical VDO oi press. guages though.
so ......what i'd say is
YES, you do have more of a preceptional problem than a real one.....
but you also have a bit of a real problem, related to bearing oil clearance.
15psi at 60 mph hot at say 3,500 rpm ............if that's what you are
seeing ..........that's on the low side for sure.
I'd like to see 20 there.
Seeing zero oil pressure at a hot idle...
I've seen engines do that and do it for years, though not a waterboxer
engine.
that's my vote ...........oil clearances on the crankshaft are on the loose
side of spec, and that's where the oil pressure is not getting generated
like you'd like to see.
the oil system parts........oil filter , oil pump, oir pressure relief, pick
up tube inside the engine .......
those all do come to mind, but it's very unusualy for there to be a real
problem with those......'mostly'
I have seen about 10,000 different failure modes in VW engines over the
years,
so I never say never.
oh .......here !~ do this !~
well worth in this case.
send a sample of the oil out to an oil analysis lab.
that report can tell you a lot (costs like 40 to 60 bucks ) and sometimes
you can even talk to an oil engineer about your engine .......
that combined with roughy 30 things they tell you about the oil.........can
tell you a LOT !
you see higher than normal tin in the oil...........or copper ...........you
think of bearings.
If the oil pump had already been replaced before you ........
if that was during isntall of a rebuilt engine IOK, .....but normally
..........I'd never expect to see that a waterboxer engine has its oil pump
replaced.
Like unless it's a fluke faulty oil pump .....
they are almost never suppossed to need an oil pump ......it's not a normal
wear item ....'usually.'
bearing oil clearances are on the loose side, that's my vote here.
it could have say .........
looser than spec cam bearing oil clearance.......and oil pressure is being
lost there.
but it it's not temp, or the oil, or the pump or things that control oil
pressure , .....is my hunch here, and that usually leaves you with oil
clearances being too large.
Dr. Shazam prescribes an oil analysis on your engine. Google it and pick
the lab you like.
Iv'e used Hergurth in Vallejo Ca if they still exist.
scott
www.turbovans.com
scott- aka Dr. Shazam.
----- Original Message -----
From: "Dave Mcneely" <mcneely4@COX.NET>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Saturday, August 08, 2009 7:33 PM
Subject: temperature-oil pressure (rather long)
> My '91 Vanagon GL Campmobile 2.1 VW engine shows evidence of oil
> pressure drop at running temperature -- but I'm not sure it is running
> at the right temperature, either.
>
> Everything seemed ok with regard to both for the first 3 months I had
> this beast (at least once I got the after market oil pressure gauge
> working by replacing the sensor and making sure the wires were tight at
> both ends). I had a tech check the oil pressure as part of a
> prepurchase exam, and he said it was fine, nothing to worry about. I
> didn't worry until I took it on it's first highway speed sustained trip.
> Ambient temperature was around 102 - 105 F, and I drove around
> sixty-five mph (3200 rpm) for several hours. The temperature gauge
> gradually rose so that it sat above the LED, with a slight space between
> the bulb and the needle. Oil pressure dropped to around 15 psi on the
> gauge.
>
> When I stopped the van, the oil pressure reading on the gauge dropped to
> near zero at idle.
>
> I was running Castrol 20W-50 oil, with a Mehle (sp?) filter as
> recommended by my mechanic, David Hesse of Norman, Oklahoma.
>
> I took the van to Mister Mechanic (Rocky Mountain Westy) in Fort
> Collins, Colorado. Mike Labate and other techs there were very desirous
> to help, and tried cheap fixes first. They cleaned up all oil pressure
> electrical leads first, and after checking the oil pressure, concluded
> that my gauge was off by about 5 psi, and that the vehicle should really
> be ok. In fact, they thought that the oil pressure was running around
> 30 psi at 2000 rpm, and higher at higher rpm (they checked it with their
> own gauge, of course).
>
> I was pleased, and resumed my drive, headed toward Spokane, Washington.
> But, as I got out to the highway, the oil pressure reading began
> dropping, and fell to around 10 psi. I went back, at which point the
> guys checked the pressure again, this time running the engine at high
> rpm until the cooling fan came on. Pressure dropped on their gauge,
> too. On noting that the air flow meter had recently been changed, the
> techs suggested the engine may have been running rich and contaminated
> the oil prior to the AFM change. I was eager for a cheap fix, and
> though I'd changed the oil after David Hesse had put the new AFM on, I
> went along with the oil change. New Castrol 20W-50 and new Bosche
> filter. Same situation. Mike recommended a new oil pump.
>
> I agreed to the new pump, which meant an overnight stay in Fort Collins.
> Camped along the Poudre River west of town overnight -- nice.
>
> Next day, new oil pump, and new water pump, found to be leaking when van
> was raised to put in the new oil pmp. I wasn't happy about the leaking
> water pump, as I had just replaced it, but it was clearly leaking.
> Mike showed me the old oil pump, and what he said was "some wear" on the
> gears. Also, the tech who actually put the pump in showed me on the old
> pump where he said sealant had been gunked on too thick, which he said
> might have allowed the pump not to engage the oil properly (slight
> reduction in the depth to which the gears penetrated into the oil).
> There was even some sealant on the pump gears themselves. At any rate,
> new pump -- expensive.
>
> Made no difference. Mike then said that the oil pressure was adequate,
> despite the readings on my after-market gauge, and I really should
> complete my trip without worrying. I explained that my immediate
> destination was Spokane, long drives, long climbs on grades to get
> there, then to Great Basin National Park in Nevada -- through hot
> country, long, steep climbs. He repeatedly said he thought the engine
> was oiling adequately, especially since it ran so well, never clattered
> or knocked -- in fact ran very smoothly. With few other options for the
> time, I continued toward Spokane, but planning to check further there,
> when I would have more time, and almost certainly not to complete the
> hotter, steeper legs of the trip beyond. On a test drive with a tech,
> the tech noted that the temp gauge was running above the level that he
> thought was "normal." The needle on mine holds above the LED (slight
> space), whereas he thought "normal" was for the needle to hide the bulb.
>
> First overnight revealed further deterioration in the oil pressure
> readings. Whereas before, the after market gauge showed readings around
> 40 psi when cold at idle, and 60 psi when cold at running speed, jumping
> up immediately upon start, now the gauge read zero at cold idle until
> the engine warmed, and it took a bit before the pressure would rise. It
> wavered about as it rose slowly. I let it rise before driving it.
> When it did rise, it would read around 40 psi until it reached operating
> temperature -- temp gauge needle above the LED slightly, then the
> pressure would drop to around 15-20 psi on the gauge. By this time I
> was several hundred miles from Fort Collins toward Spokane. I elected
> to continue the trip, but not to drive the van in the mornings until the
> pressure rose. At operating temp, again, the gauge read around 15-20
> psi, and near zero at hot idle.
>
> Upon reaching Spokane, I called a called a vanagon mechanic who was too
> busy to help me, but who referred me to another shop whom he said also
> had expertise in vanagons, Barry's Downtown Automotive Specialists.
> That was on Friday, and Barry said he could look at the van on Monday.
> When I got there Monday morning I noticed several old VWs, including a
> couple of Vanagons, in the lot.
>
> Barry suggested the best thing to do for the immediate term was to
> change the oil to 50W Valvoline, and to baby the vehicle home. I
> agreed, we changed the oil and filter, and the vehicle has been running
> good oil pressure at running speed and hot idle, but still has to be
> warmed up to get the pressure up from a cold start. Still wavers, still
> climbs in fits, up to around 40 psi on the gauge, holding at around 10
> psi at hot idle, 30 psi when at 60 mph, 3200 rpm, temp gauge slightly
> above the LED.
>
> But, at high ambient temperatures, long drives, climbs, the pressure
> still drops some, lower on my gauge than I'd like. I talked with a
> couple of other mechanics, one including my brother, all of whom
> suggested I had more of a perceptual problem than a real one, and that I
> should go ahead with my trip, and as some said, drive it until something
> breaks, which likely won't happen for many thousands of miles. The
> vehicle is oiling well if smooth running with no noise is evidence.
>
> I did complete the trip, driving down through southern Washington,
> across Oregon and Nevada, to Great Basin National Park (8% grade for 12
> miles, that one) through 100+ FA temps at times in Washington and Oregon
> desert country. The van never showed any sign of poor oiling -- no
> rattles, clatters, knocks. Used no oil. But, on the climbs, I had to
> rest the vehicle. Temp gauge neared to next higher line, and touched it
> on a couple of occasions. Twice, the coolant warning light flashed.
> When I rested the vehicle, it cooled incredibly fast, and so I was able
> to complete a climb even if the gauge needle rose. But, I must rest the
> vehicle, and the oil pressure reading is clearly inverse to the
> temperature, even with the 50W oil.
>
> I made it home with no problems, including steep country in northern
> Utah and Colorado, but once I got back into hot country (eastern
> Colorado, Oklahoma) the van generally ran with more space between the
> temp needle and the temp LED. Oil pressure was ok, and I never
> experienced a mechanical problem. I finally tried the air conditioner
> on the final leg home, as the outside temperature was well above 100 F.
> Temp needle rose to slightly above the middle of the space between the
> LED and the next line. Of course, the owner's manual defines this as
> within the "normal" temperature reading range.
>
> Through all this, oil showed full on the stick, and coolant level was
> never low. Both low and high speed fan operation was fine. Boy, the
> high speed one really roars! On downhills, the temp needle drops so
> that it touches the top of the LED.
>
> This Westy shows 140K on the odometer. I got a receipt from the seller
> showing an engine replacement (rebuilt, but not bored to a higher
> displacement) at 110K.
>
> On the trip home, I stopped back by Rocky Mountain Westy and talked with
> Mike again. He offered to check the oil pressure cold -- would need the
> van overnight to be confident it was cold. I had to get home. Also
> offered to check actual operating temperature to be sure gauge was
> correct, but realistically, the behavior shows coolant operating
> properly -- fans kick on as expected, everything heats up as expected,
> engine cools rapidly when resting and on downhills. Oh, the van has a
> new thermostat.
>
> Mike discouraged me from thinking that flushing the cooling system was a
> helpful approach -- suggesting that he'd essentially already done that
> when he drained the coolant when changing the water pump, and that due
> to the radiator configuration, flushing doesn't clean it any better than
> simple draining. Hmmmmm. He did suggest changing the fan switches to
> cooler ones -- cheap, might help. He couldn't get the switches early
> enough since I had to continue home (and I was confident at this point
> that I'd make it home).
>
> So, I drove the thing over 4,900 miles, mostly at highway speeds, made
> some long, steep climbs. It did get hot but didn't overheat --
> certainly not seriously, but ran continuously hotter that some folks
> said was "normal." I would rather be able to use 20W-50 oil than 50
> weight. I also don't like having to warm the vehicle up to get the oil
> pressure up -- one isn't supposed to do that with any engine built since
> the sixties -- though VW does say drive gently until it is warm. This
> one had good oil pressure when cold until the new oil pump was
> installed.
>
> Fixes I've considered include trying the flush despite Mike's dissuasion
> to see if that helps with the temperature, and therefore indirectly with
> the oil pressure. But it won't help the cold oil pressure, that's
> certain. Then if the flush doesn't help, move to trying to change out
> cooling system components in order of expense -- cheapest first, moving
> up to the radiator. I can't believe that the water pump is weak again
> -- I put a new one on it when I first got the vehicle, then it leaked
> and I put the second one on. New thermostat -- guess I could try
> another, but it really seems to be working well -- coolant temperature
> rises steadily until it stabilizes just above the LED on the gauge.
>
> Any suggestions from anyone who has been patient enough to read this far
> would be much appreciated. I really am now convinced that the original
> oil pressure drop was due to high operating temperature, but -- the
> newly cropped up problem of low pressure until slightly warmed up -- the
> new oil pump is weak? It is supposed to be a "heavy duty" pump.
>
> David McNeely, Edmond, Oklahoma
>
> Thanks in advance, David McNeely, Edmond, Oklahoma
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