oil light didn't go out

[whc03grady]

After 15 minutes of highway driving, the car dies at the stop sign. It started right back up, but the oil light didn't go out. Since I was 30 yards from home, I just drove it. The light stayed on through 1st gear and into 2nd, going out right before I parked it. That is, it shone bright as anything right through ~3,000 rpms. The oil is exactly at the top line, nice and clean looking, no smell, Castrol 20W-50.

The engine seems to run hot even after shorter runs. By this I mean that if I drive it for half an hour it'll get hot enough that you can't keep your hand on the fan shrouding, or even the bumper. It takes probably a couple hours until it's cool enough to touch and several hours before it's cold. At shutdown you can smell heat--not burnt oil, heat--pouring out of the downwind air scoop. Outside temps have been in the 80s.

There is no thermostat installed currently, as I somehow destroyed the one good one (a Type I) I had. The flaps are therefore always in the 'hot' position (I have visually confirmed this).

[Amskeptic]

After 15 minutes of highway driving, the car dies at the stop sign. It started right back up, but the oil light didn't go out. Since I was 30 yards from home, I just drove it. The light stayed on through 1st gear and into 2nd, going out right before I parked it. That is, it shone bright as anything right through ~3,000 rpms. The oil is exactly at the top line, nice and clean looking, no smell, Castrol 20W-50.

The engine seems to run hot even after shorter runs. By this I mean that if I drive it for half an hour it'll get hot enough that you can't keep your hand on the fan shrouding, or even the bumper. It takes probably a couple hours until it's cool enough to touch and several hours before it's cold. At shutdown you can smell heat--not burnt oil, heat--pouring out of the downwind air scoop. Outside temps have been in the 80s.

There is no thermostat installed currently, as I somehow destroyed the one good one (a Type I) I had. The flaps are therefore always in the 'hot' position (I have visually confirmed this).

Did this "hot" symptom recently develop? Can you actively move the flaps and hear them clank in the open position? Can you feel a blast of hot air under the bumper when you rev the engine? Check your plugs for brownish insulator color. If they are white, the mixture is dangerously lean.


Have you checked the oil sender/wiring?
Will the idiot light go out properly when the engine is cold?

Did I ever tell you that you can blow up the engine within a second if you run the engine at operating speed with the oil lamp on?
Dead serious. Read this again:
Colin

[whc03grady]

Did this "hot" symptom recently develop?

This has been going on ever since the new engine was installed, though sometimes it doesn't seem as bad (i.e., as hot) as other times. I don't know what distinguishes the hot vs. the not-as-hot cases.

Have you checked the oil sender/wiring?

I've checked it in that I've determined that it's seated well at the sender end and the wire doesn't look melted or anything. The light comes on with the key, like normal. It also sometimes flickers at low rpms.

Will it go out properly when the engine is cold?

You mean, right at start-up after it's been sitting, does the light go out? Yes. Definitely first thing in the morning. Sometimes, when it dies at a stop sign (which happens more often than not after a highway drive), the light does seem to stay on for a tiny bit longer after the engine starts again.

Did I ever tell you that you can blow up the engine within a half a second if you run the engine at operating speed with the oil lamp on?

You never told me that, but I knew it anyway. I've done it before, myself (1973 Fastback, Summer 1991).

I'm so disappointed with this whole situation--in my ignorance I figured I'd pop my brand-new, expensive, professionally built engine in, put the just-rebuilt carbs on it, and after some tweaking, I'd ride off happily into the sunset for 100,000 relatively trouble-free miles.

Stupid me.

Maybe subconsciously I don't care if I destroy the brand-new, expensive, professionally built engine. At least it would definitively justify what is increasingly evident: we need to bite the bullet and get a normal, boring, modern, soulless car because I'm not the kind of person who is capable of keeping a 38 year-old vehicle and a 41 year-old vehicle in dependable driving condition.

[Amskeptic]

This has been going on ever since the new engine was installed,

Dual carb buses that stall coming up to a light need more air/fuel in the central idling circuit. Idle speed should be as close to 1,000+ rpm as possible without the centrifugal timing getting excited.
Check the plugs for white.
Colin

[whc03grady]

I changed the oil as part of a tune-up (or rather attempt at a tune-up; it still dies more often than not when you let off the gas, like at stop signs, and especially after a jaunt on the highway, but I digress) and put in exACTly 3.5 quarts (3.31 L) of Castrol 20W-50; 3 qts in the case, 0.5 qts in the new filter. This is 0.2 qts (0.19 L) short of how much the owner's manual says to put in, but it's welllll past the 'full' mark on the dipstick.

Anyway, coming off the freeway (about 8 miles at a steady, flat 63mph, outside temps in the low 80s) the thing stalled. I popped the clutch and it got a-running again, albeit with the oil light still on. Heeding warnings about 0.5 seconds to a blow-up event, I turned it off and rolled to the stop sign at the bottom of the ramp. I cranked it up again, and that light stayed on. Ignoring warnings about 0.5 seconds to a blow-up event, I blipped the pedal to no avail--light's still on. I turn it off again and mosey rearward for fun. No unusual hot smells, no oil pouring out, nothing. I fired it up again, the light went off, and I drove home. After it cooled down, the oil's nice and clean, and still too full according to the stick.

Why does this light keep crying wolf? Is it crying wolf? Is 0.2 quarts low (dipstick quite to the contrary) enough to trigger the light when the oil's nice and warm? Is 20W-50 the wrong weight?

[RSorak 71Westy]

Based on my recent experience yes 20-50 is too thick, unless your engine has bunch of miles on it and is very tired. But it will not cause the symptoms you experienced.

If it is really overfull, the oil can foam, and this can reduce the pressure.

[whc03grady]

Based on my recent experience yes 20-50 is too thick, unless your engine has bunch of miles on it and is very tired. But it will not cause the symptoms you experienced.

If it is really overfull, the oil can foam, and this can reduce the pressure.

The engine doesn't have 900 miles on it.

[RSorak 71Westy]

Then you dont need 20W50. If you have over 45 or so lbs of oil pressure in a VW engine at speed on the highway the oil will never go thru the oil cooler. You should be running 10W30 I bet. That's what my engine needs to have the right oil pressure at speed. When I ran 10W40 I had 60 lbs of oil pressure and HOT oil. With 10W30 I have just over 40 lbs at speed and much cooler oil.

[Gypsie]

Have you ever had bubbles on the dip stick?

Have you tested your running mix with an LM1 or ???. I am interested in how you adjust mix on a 71 Square.

The blipping light doesn't bother me as much as the dying engine (that could be a symptom of overheating)...
but the light could be telling you something about what is going on in there.

Of course the "professionally built" part intrigues me. Local Shop? Proper engine breakin' procedures followed? Swirlies in the oil?

Do you have the tools to get an oil pressure reading? Gauge?

Have you taken it to the shop that built the engine for some feedback and to establish a starting point for a complaint (should you find yourself wanting to make one). 900 miles is not much (as I am sure you know.)

I have some percolating thoughts about what kind of things may be happening but am a little hesitant to suggest improper engine building. (ie reground/or polished crank could have left polishing compound in an oil galley. When we we working on Hambone's engine we discovered gobs of the stuff in the crank galleys that required a wire with a wad of fabric pulled through to clear when we were washing it in the sink. I felt like that was a serious dodged bullet because the polishing compound had 'grit' that would have worn bearings very fast had it peen pushed out of the galley into the bearing raceway.)
Anyway, I don't want to plant seeds of doubt, just trying to do some figgerin' with you.

Oooh, I just saw Rsoraks post. I like it. Makes sense.

[satchmo]

Then you dont need 20W50. If you have over 45 or so lbs of oil pressure in a VW engine at speed on the highway the oil will never go thru the oil cooler. You should be running 10W30 I bet. That's what my engine needs to have the right oil pressure at speed. When I ran 10W40 I had 60 lbs of oil pressure and HOT oil. With 10W30 I have just over 40 lbs at speed and much cooler oil.

This makes no sense. If the pressure is so great from the 20W50 oil that it doesn't flow through the oil cooler, then it should certainly be enough to keep the oil pressure sender from triggering the light, no matter how hot it gets.

Or am I missing something?

Tim

[RSorak 71Westy]

This was not meant to address the oil light issue, that's still an unsolved problem. I was just providing info about oil viscosity based on my recent learning experience in this area.

VW engines are designed to bypass the oil cooler when oil pressure is over 45 lbs, the assumption being if the oil pressure is this high it must be cold and thick and not need cooling. If your engine runs more than 45 lbs at speed you need to run thinner oil, if you want it cooled.

[vdubyah73]

faulty sender? shorts internaly when hot? lifters get noisy with light on?

[Amskeptic]

I changed the oil as part of a tune-up (or rather attempt at a tune-up; it still dies more often than not when you let off the gas, like at stop signs, and especially after a jaunt on the highway, but I digress) and put in exACTly 3.5 quarts (3.31 L) of Castrol 20W-50; 3 qts in the case, 0.5 qts in the new filter.

The engine takes 3.75 quarts. So why are you under-filling it? That is bad for camshafts and cylinder wall lubrication and oil starvation at stop lights.

I have posts in the prior itineraries where the Road Warrior scared the hell out of me with a leering oil light, and it was the stupid oil level being down. Type 4 engines, I don't care what They Say, like a full oil level and if you accidentally go above the full mark, so much the better for your camshaft.
Colin
( you WILL report back on oil light behavior after getting the upper dipstick mark covered with the 20-50! nectar of life Castrol GTX , yaah, my little budding Master Mechanic??? Heck, I'll ask the advanced question right now, please inform us if you have an oil control valve between the pushrods on the right side of the engine, check any photographs you have of your engine teardown)

[whc03grady]

The engine takes 3.75 quarts. So why are you under-filling it?

'Cause the Bentley told me to.

You WILL report back on oil light behavior after getting the upper dipstick mark covered with the 20-50!

But it's well above the upper mark now! In fact, it's a whole low-to-full-length's length above it! Thus:
Dipstick End-------------------Low--------Full--------Me------------------------------------------------------Handle

[Amskeptic]

The engine takes 3.75 quarts. So why are you under-filling it?

'Cause the Bentley told me to.

You WILL report back on oil light behavior after getting the upper dipstick mark covered with the 20-50!

But it's well above the upper mark now! In fact, it's a whole low-to-full-length's length above it! Thus:
Dipstick End-------------------Low--------Full--------Me------------------------------------------------------Handle

When you say it is above the mark now, does that mean your symptoms have been with this "above the mark" reading?
Are you saying that it is above the mark even at only 3.5 quarts? Is this a nice normal dipstick, or has it been filed?

A whole low-to-full mark length above the full mark is not OK. Drain it down. Let us know if the oil light behaves.
Colin