Mysterious noise at startup

[superdubbr]

My '72 SB daily driver (stock 1600DP) always starts like a champ and runs smooth and strong. I've driven it over 10k miles this year. However, there are a couple of things that concern me - here's the major one.

Whenever the car sits for more than 1/2 hour or so, when I first fire it up, the engine sounds loud, like there is no oil pressure. Sort of a "dragging" sound. The oil light does not come on and the sound stops after about 2-3 seconds. Not sure if it is dry cylinder walls, bearings, or something to be concerned about? Is this normal?

Also, after a long run on the highway on a hot day, the oil light will flicker at idle. Goes out instantly if I step on the gas. I run straight 30w Shell Rotella. I think the engine runs a bit hot in this weather as the dipstick is pretty uncomfortable to the touch.

Reason I ask is that I have the engine out right now to fix oil leaks. Anything I should be concerned about here? Should I be replacing the oil pump? Is it possible my engine bearings are nearing the end of their life? If I believe the PO, the engine now has about 50k on it. (Not the original engine.)
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Blue '72 Super Beetle - 1600 DP

[Cusser]

What do you mean "no oil pressure" ? Does the warning light stay on for a few seconds, or are you utilizing a gauge (if so: mechanical or electronic sending unit) ?

After a run at operating temperature, it is common for an oil light to flicker, don't worry about it.

By the way, a stock oil sender unit is quite inexpensive, and very easy to swap out, a five minute job which includes finding your 24mm wrench or socket.
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1970 VW (owned since 1972) and 1971 VW Convertible (owned since 1976), second owner of each. The '71 now has the 1835 engine, swapped from the '70. Second owner of each. 1988 Mazda B2200 truck, 1998 Frontier, 2014 Yukon, 2004 Frontier King Cab. All manual transmission except for the Yukon. http://www.thesamba.com/vw/forum/album_page.php?pic_id=335294 http://www.thesamba.com/vw/forum/album_page.php?pic_id=335297

[jlex]

Notice anything sparkly in the oil when you change it? Would indicate wear is occuring due to a lack of lubrication or some other problem. If nothing out of the ordinary, that's a good sign.

[superdubbr]

Forgot to mention, I am running a VDO twin output oil pres sending unit that I picked up last year. Right now, I am only using one terminal to run the stock oil pres warning lamp. When I bought the sender I was planning on adding an oil pres guage, but I haven't gotten around to it yet. (Read on here that aftermarket oil pres guages aren't so great so I put that one on the back burner.) I think the oil pres lamp is working ok. The oil light comes on when you turn the ignition on, then goes out immediately and stays out when you engage the starter and the engine fires.

By no oil pressure, I meant that it sounds the same way most engines do when you have just changed the oil and you first fire them up. (My wife's Acura Integra does this...I assume it is because it takes a second to get oil pressure when the filter is empty.) The oil pres light goes out as soon as you crank the engine. But the engine (bearings?) sound louder for a couple of seconds and then quiet out. It doesn't do this if you shut the engine off for just a few minutes and then restart.

It's done this for the last 10k, I just figured it was because there is no full-flow filter and it takes a second for the oil pump to prime and deliver pressure. Am I wrong?
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Blue '72 Super Beetle - 1600 DP

[superdubbr]

I haven't seen anything sparkly...not running a magnetic drain plug. Are they a good idea? I did find some black crud on the top of the heads around the valve drain (doubt that is related to this issue.) The first time I adjusted the valves (when I got the car) I cleaned this all out. I do find bits of it in the oil screen every time I do an oil change. Haven't seen anything else fishy though.
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Blue '72 Super Beetle - 1600 DP

[bjet767]

"But the engine (bearings?) sound louder for a couple of seconds and then quiet out. It doesn't do this if you shut the engine off for just a few minutes and then restart. "

Sounds to me more like lifters than bearings.

I have had failed bearings before and you will notice them and it will not go away as the engine warms up. Additionally your engine will run very hot if a bearing is failing.

I would check cold valve clearances.

[jlex]

Ditch the straight 30W and try 10W-30 on your next oil change. The 30W maybe is too thick at startup.
RE your wife's Acura: when you do an oil change, fill up the new filter w/ oil before installing it. Should help get oil to the engine sooner.
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jlex.
'70 std. "Elsie"
'88 Carrera

[Cusser]

It seems that the VDO twin sender idiot light part is set to turn the idiot light on at an oil pressure lower than the stock sender.
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1970 VW (owned since 1972) and 1971 VW Convertible (owned since 1976), second owner of each. The '71 now has the 1835 engine, swapped from the '70. Second owner of each. 1988 Mazda B2200 truck, 1998 Frontier, 2014 Yukon, 2004 Frontier King Cab. All manual transmission except for the Yukon. http://www.thesamba.com/vw/forum/album_page.php?pic_id=335294 http://www.thesamba.com/vw/forum/album_page.php?pic_id=335297

[Bruce Amacker]

PPS: Try an OEM (Honda) oil filter on your wife's car- many times it makes a big difference in startup noise, as the aftermarket filters may omit the drainback valve.

PPS: An oil analysis from Napa/Wix is a cheap way to see what's wearing out inside your motor. PN 4077, $14.

Good Luck!



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'66 Deluxe Bus
'65 Standard Bus
Build threads:
'66- http://www.leakoil.net/forum/viewtopic.php?f=23&t=2888&sid=54d8dedfb3822f99c7f2ea430cb4e856
'65- http://leakoil.net/forum/viewtopic.php?f=23&t=4263

[dirtkeeper]

i have had a similar experience when my carburetor was loose and another time when i had a loose cylinder head. as soon as the engine warmed a bit and expanded it sealed up. usually was loud for more than a few seconds...like a minute or more and it sounded more like an exhaust leak so may be different sound then yours.

[DrDarby]

I thought loose cylinder head but the oil light flickering made me think. Many years ago I picked up a 71 beetle that was a travelling salesman's car. It had 185,000 miles and the rebuilt engine had about 75,000 miles on it and I was told it siezed and was parked in the garage where it sat about 8 years. It was three blocks away so I had a friend push me home with his car where I noted the engine was not siezed. An hour or so later I had it running and it ran well. It always knocked badly on cold start and the oil light flickered at hot idle but I was young and figured I'd drive it until it graduated into something worse. After driving it daily for 18 months my Dad retired and took another job about 40 miles away and I gave him the bug and swapped the engine with a low mileage original from a wreck. I split the case on this engine and found one of the main bearings must hae siezed at one time and the dowel pin now fit in a groove so the bearing was actually floating somewhat. I'll never figure out how it never locked up on my in all the miles I drove it as I'm sure some of the time the oil passage must have been closed off.
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Midwest Autosavers, Inc. Crystal Lake, IL