Date: Tue, 10 Nov 2015 19:23:20 -0800
Reply-To: Stuart MacMillan <stuartmacm@GMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Stuart MacMillan <stuartmacm@GMAIL.COM>
Subject: Re: Oil pressure light and buzzer Checking engine grounding1
In-Reply-To: <BAY405-EAS290C7060CC70C13807A1A00A0130@phx.gbl>
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This is so important. I bought my first Vanagon, an '84 Westy, in 1986 with 30k miles on it. At 45k one of the heads leaked, and the dealer replaced both heads under a "partial" warranty--VW gave me one new head, the other for 50% off ($400) and a gasket kit, but the dealer charged $1000 for the labor to install them. This was in 1988, about $2800 today!
I also got 205,000 out of this engine before I replaced it with a rebuilt 2.1. It was running well, I just wanted more power.
I had a conversation about why this happened with the tech who did the job, and he thought the head corrosion problem he saw so much of was from bad/failed engine grounding. They also replaced the engine ground strap and he recommended that I run a 6 ga wire from each head to the case, and showed me where to attach it.
Makes sense when you think about it. The heads have a rubber gasket between them and the case, rubber hoses connect them to the intake plenum, and the cap nuts on the studs have sealant under the flange. This leaves the cylinders, exhaust system, and push rods to complete the ground connection to the case, which is completed to the chassis by the engine & transmission ground straps. This is a connection system that is ripe for high resistance over time and floating micro-voltages that can cause electrolysis.
Extra grounds can't hurt.
Stuart
-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of Dennis Haynes
Sent: Tuesday, November 10, 2015 6:23 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Re: Oil pressure light and buzzer Checking engine grounding1
You are onto something. I never mentioned it for this symptom as a bad ground on the engine can cause so many other problems. The alternator path includes the engine case and the grounding at the left head and transmission. If there is a higher resistance there than there should be you will get a voltage drop that will appear between the engine case and the chassis. This can interfere with the oil pressure warning system as that signal has to go to 0 to keep the light and buzzer off.
With the engine running and a lot of electrical consumers on measure the voltage between the engine case and the chassis. If you see a voltage approaching 1/2 volt or more that is a problem. After repairing the original grounds a separate on from the alternator to the chassis is a good idea. I have also found that excessive resistance in the power circuit from the ignition switch back can also cause havoc.
Dennis