Overheating - kind of urgent

May be totally normal. Buy some kind of turkey thermometer which will fit in the dipstick hole and measure what the oil temp *really* is. (Or get an electric temp gauge; I assume the one you have just makes an alarm contact.)

At 90F ambient, pushing a Bay Bus at 65, oil temp can _easily_ go to

230F. Remember that oil does not boil at 212F so there is nothing magical about that number!

Use a heavier weight oil.

Speedy Jim

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Doesn't sound at all like a put-down. Sounds suspiciously like good advice. Like good advice coming someone who knows these buses better than I.

Earlier, in another thread a week or so ago, I inquired about additional oil cooling (some thread about full-flow) and -- Jan? Olli? I forget -- said that if the bus is overheating then I have real problems.

Mr. Bushy Tail:

Cooler is better (to a point) so an additional external oil cooler and full-flow (with filter) is still a good thing. You live in a warm climate. Maybe you should consider it.

My favorite is the Setrab cooler. Choose the smaller. With electric fan. Very nice setup.

It was hot on Sunday. I was driving down 680 from Walnut Creek to Dublin and my oil temp rose to 260 degrees. Needless to say, I stopped for a bit in Santa Rosa and bought a soda and let it come down to 210 before continuing.

I learned an important lesson yesterday. When one adds goodies to increase the power of an already underpowered bug, external oil cooling is a must. I'm now convinced that VW engines are really oil cooled. Yeah, the fan cools the cylinder heads, but everything else like the block itself seems oil cooled.

-------------------------------------------------

The oil temp is the SYMPTOM, not the problem. You can add all the additional oil cooling capacity you want, if you don' deal with the basic problem you'll still end up trashing your engine.

Pushing a bus 65 along Hwy 78 (assuming it's not a parking lot) is silly when it's this hot. The Owner's Manual tells you to take your foot out of it when heavily laden or during hot wx.

Oil temp & oil pressure are a binary data element; you need both, properly measured, to know what's what. Measuring OT at the dip stick or sump plate will give you a fallacious reading. VW industrial engines (the only ones that came with a factory-installed oil temp gauge [all of the others are After-Market add-ons]) measured the oil temperature at the inlet to the oil pump. Engine management data isn't a popularity contest; the fact all the kiddies use dip stick guages doesn't mean the things are any good.

You can get 2,000 hrs of trouble-free service or more from a properly built VW engine... assuming it is operated within its design parameters. That can mean puttering along at 35mph during really hot weather.

The service life of your engine responds to one of those nasty inverse-cube equations. Operate outside the envelope, you'll reduce the service life by an order of magnitude. Which is exactly what some people want you to do.

Start thinking for yourself. The information is out there.

-R.S.Hoover

I have to disagree with the assertion that the ACVW is oil cooled. Look at the later model air/oil cooled BMW motorcycles which really are oil and air cooled. The oil cooling is accomplished by specific design - through the heads. The rest is largely air-cooled because if you cool the heads, then cylinders, the case and contents will follow.

Jake Raby built a 2165cc Type-1 engine with high compression that stays amazingly cool. The heads are 041s, the cylinders are aluminum, carved from billet and nickelsil plated (no iron). Cooling is T1 upright tin. Even without the oil cooler fan blowing, this engine stays cool and when it gets hot, it cools down very quickly again while still running. Yeah, even in 100 degree weather.

A possibly controversial addition to the engine is ceramic headers wrapped from the exhaust ports to the muffler. (Carbon impregnated wrap) and a very well sealed engine compartment. I personally don't know of any ACVW that's as well sealed as this one, nor wrapped as well. The engine compartment is _cool to the touch_ even after a hard run. You can put your hands on the headers within two minutes of shutdown. It's cool.

That's a lot of words, but I don't know how to make it clearer.

I love that statement. I'd like to pour concrete around it and have it signed "by Bob Hoover". Another for the ACVW monument yet to be built.

John, What IS the CR of your engine? Or is it classified info? Why would the header treatment be controversial? Isn't the idea to keep the header hot? (On the inside) (Gotta go back and study my heat transfer theory again!)-BH

David Gravereaux

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Ahh ha.. You got an oil cooler.

Yes, iron retains heat better than the ln engineering "nickies" cylinders.

10.2:1 which I understand isn't so high anymore with squishy pistons. Someone else would have to help there.

I was guessing on the controversial part. Header wraps raise arguments here, but not among the racers. As you mentioned, they keep the heat where it belongs, in the pipes for faster scavenging, and keep raidant heat away from the engine.

Of course, but an oil cooler alone won't make the Big Difference.

It does if that's the "item" becoming overheated. Let's say the iron cylinders transfer loads of heat to the block as compared to the nickies. What then cools the block? Oil.

The oil system isn't designed to cool the case. If it were, you could be damned sure it wouldn't have the current design of the path of the oil, the area of the path, and flow rate. With the oil cooler you are, hopefully, bringing the oil to a reasonable temperature so that you don't destroy the oil which in turn will let the engine destroy itself.

So keep the ACVW in proper tune, the tin in proper configuration, and the foot off the pedal in hot weather - or re-engineer it properly.

Symptom: engine overheating. Problem: Uneducated driver.

You're not just whistlin' Dixie, Bob. Going east it was pretty much a parking lot -- some accident near El Camino Real -- and I had a bit of a tailwind. But coming back to the coast, traffic was light. So I took 'er to cruising speed.

Anyone know where I can get a 71 Transporter Owner's Manual? Still looking. Got a bounty on it.

The good thing about the Berg dipstick is that, even as poor an instrument it may be, if I hadn't installed it, I would have had no idea that I was pushing the Wonderbus so close to its performance limits. In an earlier thread, "The Good Oil Filter," I wrote,

"But, here in SoCal, when the Santa Ana winds are blowing hot, dry air off the inland valleys in September, and temperatures are over 100F (38C), and the Wonderbus is hauling kids down the highway, I can't help but wonder if I should expand my oil considerations by adding more than just a good filter system, but also a temp sender, and additional cooling -- done right."

And Jan, who lives in Finland I think where 38C days may be fairly rare offered that,

" . . . the level of engine performance we are talking about here, does NOT warrant an external cooler. If the engine overheats, there is a problem. Either something went wrong, or the engine was built wrong. Mismatched parts, sizes, too much compression, too low octane gasoline... missing tin pieces, running lean.... An extra cooler will only hide those problems, not fix any of them."

The dipstick alerted me to the possibility that one of the problems he mentioned might need addressing. Others, more familiar with how a bus can be expected to perform in this weather, have chimed in now and provided an additional possible problem: me + heavy foot on gas pedal.

Frankly, I am relieved to learn that this high temp condition is to be expected, and not necessarily due to some boneheaded mistake I made when re-working the engine's cooling bits.

Which is what I will do. This plucky squirrel attempts to learn as he goes.

Nah, I don't think Jan is up to anything sinister.

And part of acquiring information is asking others who have a head-start in this area of knowledge which is new to me. At first we don't have enough depth of knowledge to separate the information from the mis-information, we read, we ask, we tinker, we make mistakes, we learn. As our knowledge deepens we start seeing how things work. Then we can offer advise to other tyros.

--------------------------------------------------------

The Owner's Manual for the bug, square-back and 411 sez exactly the same thing: Hot wx, heavy load, take your foot out.

The fuel-injected Mexican-built beetle went even farther -- the on-board computer reduces the injector on-time when the engine temps approach the design limits, eventually shutting the thing down if the driver doesn't shift down, slow down or what ever.

-Bob Hoover

As in, "Hmmm . . . sure is hot today. Yep, this is a hot one all right. There's the freeway on ramp . . . but wait! I better take the surface streets. Or find a cool, dark place to hang out in until the temp drops. Like a Hooters."

In this case, the on-board computer would be me.

10 BEGIN MAIN 20 IF HOT THEN 30 REDUCE LOAD 40 ELSE 50 BEGIN SUBPROCEDURE MELTDOWN 60 END MAIN

(apologies to guys that know how to write code)

while () { if (hot()) { $gaspedal--; } if (toohot()){ meltdown(); break; } }

(break is an actual instruction :)