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Date:         Wed, 15 Sep 2004 21:12:24 -0400
Reply-To:     Dennis Haynes <dhaynes@OPTONLINE.NET>
Sender:       Vanagon Mailing List <>
From:         Dennis Haynes <dhaynes@OPTONLINE.NET>
Subject:      Re: Disappearing Coolant - Head Leak?-Engine Oil Viscosity!
Comments: To: Vince S <gipsyflies@COMCAST.NET>
In-Reply-To:  <002401c49b84$063dfa90$c200a8c0@vsovaio>
Content-type: text/plain; charset=US-ASCII

5w-30 in a Vanagon is not appropriate or even safe for use in the Water boxer for extended high speed operation. It may work for a while, but eventually you will have oil pressure problems and you will eventually get to do that rod bearing replacement.

Here are the major reasons: The oil pump is of an outdated, 2 gear design. As the engine warms, the housing expands increasing the clearance between the housing and the gears. This reduces the pumps efficiency (internal slip or leakage) and the pump can not maintain pressure as the oil viscosity also goes down with heat.

In addition, as the engine warms up, the bearing to crank clearances also increase allowing more leakage which requires more flow from the pup to maintain adequate oil pressure. The aluminum engine case adds to this as you will also get leakage outside the bearings as the engine ages. This is why proper rebuilds need to have the case align-bored.

The Vanagon engine operates at higher speeds for longer periods than most engines. Find another vehicle that needs 4,000 rpm to do 70 mph! Due to the shallow sump and parts turning/churning in the oil, oil temps can sky rocket and get out of control. It is not unusual for a stock 2.1 to get the oil over 260F. The stock lube system will not maintain 10 psi/1,000 rpms with 5w-30 under these conditions.

Oil viscosity should be selected for the maximum that will allow the engine to start and get lubrication at the coldest temperature expected. With multi-weight oil the lower # represents the viscosity at 40C, the higher number at 100C. You also need to look at pour points to see how low a temp. Oil can be used. It is at the extremes where most synthetic oils shine. The Mobil 1 15w-50 is rated to flow at -35F. I find it is OK in the Vanagon to ~10F. There is now a 0w-40 designed for the European cars. Even the newer VWs have engine problems using the 5w-30s. I have been using this in my Fox and the wife's Audi with great success.

Honda and Ford are now recommending 5w-20 for some of their engines. These engines are specifically built to use these oils in the hope of improved fuel economy. It may wrk there, but do not try it in the water-boxer.


-----Original Message----- From: Vanagon Mailing List [] On Behalf Of Vince S Sent: Wednesday, September 15, 2004 8:28 PM To: vanagon@GERRY.VANAGON.COM Subject: Re: Disappearing Coolant - Head Leak?

It is amazing how little useful information about motor oil is out there. I google it and the same "more than you ever want to know motor oil" I read years ago is still most informative article. There are others from oil manufacturers but most have so much marketing fluff that make me very skeptical.

I admit that using 5W30 on Vanagon may be a bit extreme. I probably should have stick with the 10W30 I have use until now.

Just because what is stated in the VW owner's manual doesn't mean it must be accurate and correct. Using very high viscosity oil is old-school thinking. The chart does not distinguish between petroleum and synthetic so I interpreted it have to tailor to the former as it is more prevalent. (I am surprised it mentions synthetic oil can be used)

Many studies have shown that majority of engine wear occur within the first few minutes of starting the engine while very little when the engine is hot. Many of which are attributable to revving the engine before the oil have a chance to form a film between the two wearing surfaces or using oil with too high viscosity.

When I first bought my Miata I was very uncomfortable with the specified low viscosity 5W30 oil (applicable to petroleum base oil as well). Now 12 years later (BTW it is 1992 not 93) the engine is still as tight.

Please refer to the very good viscosity index as well as the flash point of the Mobil 1 vs other oil.

Mobil does not make synthetic in very high viscosity must be for good reasons. When Mobil 1 was first introduced it was only available in 5W30.

Please note that the SAE viscosity designation method is a very crude notation. You cannot rely on these numbers alone to compare two diversely different quality oil. Many synthetic manufacturers will tell you that with synethic you do not need to change the viscosity for different seasons as you should with petroleum based. Synthetic oil superior resistance to thinning and molecular chain breakdown is the reason you can run significant lower viscosity grade for a given temperature and benefit from the lower frictional loss.

I would like to take some measurement of the oil pressure just to see for myself. Please see the paragraph about the oil pressure with jet boat on Amsoil's website:

Some Vanagon owners have experienced oil pressure problem with 5W30 but this could be due to 1) worn engine 2) petroleum 5W30 used in hot climate and driven hard 3) faulty pressure sensor.

I recognize Vanagon's flat engine does have some special consideration due to the lifter chatter if poor quality oil filter is used. I have never experience this problem since I switched to synthetic and use only good quality filter. My Vanagon sometimes sits not used for months in the winter.

In closing, I wonder if the oil viscosity chart in the waterboxer owner's manual is inherited from the air cool legacy which operates in a significantly much wider temperature span for a given ambient temperature as well as running much hotter.

- Vince 1989 Vanagon GL Camper 1993 Mazda Miata (for sale) 1996 Land Rover Discovery 2005 Mini Cooper S

-----Original Message----- From: Vanagon Mailing List [] On Behalf Of dave Sent: Tuesday, September 14, 2004 5:33 PM To: vanagon@GERRY.VANAGON.COM Subject: Re: Disappearing Coolant - Head Lean?

Read the manual for the Vanagon. Heavy weight oil is recommended. If you put in the thinner stuff (ok for some modern engines) you will drop oil pressure dangerously low, ecspecailly if hot weather, and high load is on engine.

I know from experience that the 5W-30 oil causes oil pressure problems.

i run Mobil 15-50 oil, I would prefer a 20-50, but mobil 1 does not make that (20-50 is recommended multi viscosity for hot (85F plus) weather)_

The problem with oil breaking down does not have to do with thicker oil breaking down sooner, the real problem is that multi viscosity oils tend to break down in viscosity much faster than straight oils.

VW even recommends straight 40 oil for hot weather operation, that is really what I'd like to use, but again, Mobil 1 does not make that product, so i stick with the 15-50.

As stated by other auuthor 5-30 oil is too thin unless you live in a freezing cold area. Also of improtance is stick with a genuine Mann, or Mahle oil filter, Fram filters have greater pressure drop, and do not have a good enough back flow valve. Fram will cause my lifters to clack like crazy after sitting several days, OEM filters solved that problem.

----- Original Message ----- From: "Vince S" <gipsyflies@COMCAST.NET> To: <vanagon@GERRY.VANAGON.COM> Sent: Sunday, September 12, 2004 10:32 AM Subject: Re: Disappearing Coolant - Head Lean?


I agree with you my coolant leak though does not appear to be the sensor and possibly the tank. I was suspectious of the tank as o-ring rarely fail unless you distrub it. I will not be surprised that it is the tank getting britle.

I will carefully unscrew the sensor and see.

I did put in 5W30 yesterday. I had in the past used 10W30 but never anything heavier. My reason is 1) Many high performance vehicles including my supercharged Mini uses 5W30 synthetic so I don't see why the Vanagon couldn't unless the bearing tolerances in it is wider. 2) I read from some good source that heavier weight motor oil is "thicken" by additives. Since synthetic have very long and strong polymer chain it is OK to run significantly lower viscosity when the spec calls for heavier petrolium based.

The Mini's official weight is 5W30 and am quite sure most BMW is the same too.

Why are people putting down Mobil 1? I have used it for years and it was one of the first synethic.

- Vince 1989 Vanagon GL Camper 1993 Mazda Miata (for sale) 1996 Land Rover Discovery 2005 Mini Cooper S

-----Original Message----- From: Vanagon Mailing List [] On Behalf Of Chuck Mathis Sent: Sunday, September 12, 2004 7:16 AM To: vanagon@GERRY.VANAGON.COM Subject: Re: Disappearing Coolant - Head Lean?


Sounds like you are definitely leaking from the sensor area. When I dealt with that problem the o-ring was intact and very subtle while the sensor was leaking. If you've got dry contacts it probably is the o-ring but it could also be a crack in the tank at the threads. I'll keep my fingers crossed for you.

Are you really running Mobil 1 5W-30 in a WBX or is that a typo? The WBX usually requires something in the range of a 40-50 weight. I ran Mobil 1 15w-50 for years but recently switched to Castrol Syntec 5W-50 cause all the FLAPS were out of the heavy Mobil 1.

Chuck '85 Wolfsburg Westy - 'Roland the Road Buffalo'

Vince wrote:

Date: Sat, 11 Sep 2004 15:16:32 -0700 From: Vince S <gipsyflies@COMCAST.NET> Subject: Disappearing Coolant - Head Lean?

I was performing my annual tune up / oil change on my 89 Westy today. I started off by checking the oil level but I notice the coolant filler/reservoir tank is totally empty. What happened? I filled it a couple of months back when it was just below the Min mark and now it is bone dry. My immediate thought of the dreaded inevitable water boxer head leak which I have been lucky so far.

I crawled under the engine to see if there is signs of the leak. Sure enough the left rear header pipe is wet and it is unmistakably coolant. Very carefully I visual inspected the head on the driver side and there is no sign of coolant residue. Suspecting the water pump I check that too and there is also no sign of coolant.

Time to look from above so I open the rear engine hatch. I can see much trace of coolant clinging to the outside of coolant expansion tank, especially what looks to be the seam of the top and bottom halves. The plastic expansion tank must developed a leak at the welded seam, I thought.

I more carefully inspected the tank with better lighting and I notice the pool of coolant in the dimple at the top of the tank where the coolant level sensor resides. Without the necessary part to repair it I didn't want to disrupt the area. I just wanted to see if the leak is from within the sensor, or leaking between the sensor and the tank. I unplugged the sensor connector and it is bone dry on the contacts so it appear the lead is between the sensor and the tank. According to the Bentley there is a o-ring. The o-ring must became harden over all this years and now does not seal under pressure. Since it is weekend I decided not to unscrew the sensor in case I need to use the vehicle during the weekend.

I was relief that it is not the dreaded head gasket leak.

I proceed to a complete tune up including changing the spark plugs, distributor rotor, distributor cap, air filter, oil filter and change the oil with Mobil 1 5W30 synthetic.

I also thoroughly wiped down the ignition wire with soap and water as well as every parts I can clean in the engine bay. If there is a cleanest Vanagon engine bay award I think I stand a good chance of winning it.

- Vince 1989 Vanagon GL Camper 1993 Mazda Miata 1996 Land Rover Discovery 2005 Mini Cooper S

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