Need advice on oil light 76 fuel injected bus

[Globedog12]

I have had the bus for only a couple weeks. Been on a couple small drives with no issues. Tonight we went out to grab a six pack and burritos then head back home. Stop and go traffic mid 80s temp. On the way home the oil light was flickering at stop lights. Revving would make it go away. Since this this is a new to me bus I don’t know what oil it currently has. It came from SanDiego and I’m in Atlanta. My first step will be to Change the oil to either 15w30 or 20w50 I also plan to install a VDO sender to monitor oil pressure. My question is what and where am I looking for to install the sender? I understand I can install a remote tee to use the stock warning light or I can attach both the light and the gauge to the sender. Idle seemed a little low but In thought oil change and pressure gauge would be good first steps?

[busdaddy]

DO NOT USE 20W50, it screws with the cooler bypass circuit and makes it run hotter. I know it's kind of like closing your eyes and falling backwards into the arms of someone who says "trust me", but the thinner the oil the better, 5W30 is even better.
An added pressure gauge isn't bad, but the stock sender is apparently doing it's job as is, and more gauges just cause a distraction and make you obsess over them when you should be watching the road. Your time would be better spent finding all the things possibly wrong with your engine and why it seems to be getting hot.
Post a whole bunch of pictures of your engine, as well as the rest of the bus, we'll spot the issues quick.

And to help you sleep better read the paragraph in the middle of this page from the 76 owners manual:

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[Globedog12]

Thanks for the reply. Haha! Yeah it’s a little scary. I thought the thinner oil would get even thinner in warmer weather and make it harder to build pressure. I will post a bunch of pictures tomorrow. I did remember reading that from the manual but didn’t think it would apply to this situation because I was at low speeds but I guess that is hard on an air cooled engine. It was pretty hot when I got home.

[busdaddy]

[skills@eurocarsplus]

[Globedog12]

[aeromech]

First, an oil light flickering at idle is bothersome but the low oil pressure isn’t hurting your engine because there’s no load on it. Basic rule of thumb is 10psi per 1000 rpm. Going 60 you want 30-40 psi. At idle a couple pounds is fine but makes the light come on.

Second, check your thermostatic flaps for correct operation. They are supposed to direct air to your oil cooler. Closed when cold for quicker warm up and then open when the engine needs the cooler.

Trust Busdaddy, he’s knows his stuff. Thicker oil won’t cool your engine.
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[Wildthings]

The operation of the flaps is not intuitive. The right one is open in the raised position, while the left on is open in the lowered position. Try looking down through the opening in the tin for the #4 spark plug and see is you can see the top of the oil cooler when the flaps are in the cold position (left flap raised). There may well be a mouse nest or other junk on top of the oil cooler. You can sometimes get away with using air or a garden hose from underneath the cooler to clean the top. A mouse nest can also block the cooling air from the cylinder head(s) and cylinders, if so removal of the tin is called for.

You also need to either replace the missing hoses to you heater booster fan or block off the holes in the tops of the heat exchangers AND seal off the holes where the hoses once passed through the tin.

The engine cooling system and cab heating system are intertwined so missing pieces or other problems in one can cause a problems in the other.

Because of the heat generated by an air cooled engine the use of either synthetic oil or straight weight oil is recommended as they handle high temperatures better than a dino multigrade.

This is a cylinder head from an 1800 in a bus that has ~200k miles on it since rebuild. It had mostly seen straight 30wt for the first 100k miles and synthetic for the second 100k. The entire engine was clean inside when torn down at 250K and had very little wear, with the cylinders having zero taper.

This is a cylinder head from an 1800 from a T4 car, it had like seen SD and SF multigrades with couldn't handle the heat, the cylinders had 0.015" of taper.

Get your idle speed set correctly.

Oil pressure and oil flow are two different things, you don't want to force your oil pressure up and end up lessening the oil flow to your bearings and other engine parts as a result.

.

[Globedog12]

Thanks for all the info. Think I’m getting somewhere. Found that the heater box opening is directly under the oil cooler. Definitely not helping my cause. I’ll find a way to block that off for now.

While I was trying to get a peek under the tim at the flap I noticed a wire that looks like it goes to a cylinder head temp sensor not hooked up to anything. Another cylinder head has a temp sensor that is hooked up. Any insight?

[busdaddy]

Trace the wire, but if the head sensor was disconnected it would barely run so something is working.

The tubes for those heat exchanger holes are sometimes in the classifieds so there's a way to do it like VW meant to if you desire, but for now capping them as well as the holes in the tin above them will definitely help with the percieved heat.
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[Globedog12]

I followed the disconnected wire to this

but the end that is disconnected is not close to anything that it would connect to
This

is the other sensor that is hooked up. It’s a mystery. I’m putting together an order to get all the proper connections to go from the heater boxes to the blower. Just got called into work I’ll do some more digging later

[busdaddy]

It's most likely plugged into that single beige colored cable leading across the motor to near #3 cylinder, the unplugged one is a spare for roadside switching without tools.

The condition of your fuel lines and the cheapo clamps on them are very disturbing, bus fires are a real issue and FI just fans the flames even faster when they do start.
You need 2-3 meters of fuel line that meets SAE J30-R9 (or the European equivalent), the size is 7.5mm although 8mm or 5/16" from the local FLAPS also fits. Belmetric.com or a Mercedes dealer for the metric stuff.
You also need a couple dozen ABA style fuel injection hose clamps.
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[Wildthings]

Your engine doesn't care which TSII sensor is in use, though the one next to the #2 cylinder is the easiest one to access, so is preferable to me. Maybe remove the sensor and put some anti-seize or dielectric grease on the threads as a good ground connection is important to its operation.

[Globedog12]

I’ll add that to the list. I’m still going to to do the oil change. Install heater parts when I get them to make sure that air isn’t blowing directly on my oil cooler when stopped. I’ll order fuel line and clamps and get to replacing. Thanks for the help. I’m sure I’ll have plenty more questions.

[busdaddy]

Oil change you say?, read all about the strainer nut first: https://www.thesamba.com/vw/forum/viewtopic.php?t=614959&highlight=strainer
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[Globedog12]

I’ve read about that one already! I’ve got my torque wrench ready

[Wildthings]

Note that if your bearing are loose, then going to a thicker oil is a viable solution. But you need to check that the oil pump is working perfectly and that the spring(s) and plunger(s) for the relief(s) are up to snuff and as I said get you idle speed up to spec. There is a fairly steep learning curve involved with all of this, and operation of the entire system is not particularly intuitive.

[busdaddy]

Indeed, there's so many things to discuss and check, like vacuum advance function and overall distributor health, engine vacuum leak situation (I see old hoses and clamps on things that shouldn't need them), fuel pressure and AFM fuckery, plug wires, plugs, tires, inflation pressures, etc....

Not the worst looking "new buy" I've seen, but there's either been a flipper, or a dumbshit PO involved, lots of things need checking to see if they cheaped out, or skipped fixing them.
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[Globedog12]

Well shit. I was hoping to get it in shape enough to drive the hour and a half to a shop. Considering contacting them next week and having it towed there to get everything checked out and get a short term/long term plan going. I’d rather bite the bullet now and get it taken care of than blow it up trying to piece it together myself.

[airkooledchris]