High oil temp and forensic engine investigation

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satchmo
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Re: High oil temp and forensic engine investigation

Post by satchmo » Tue Jun 19, 2012 6:13 pm

Hippie wrote:
satchmo wrote:Image
That looks melted more than bashed.
Has anyone seen a bus with A/C installed? This bus had A/C at one time. I think maybe that bashed in heat tube is related to the removed A/C. Thoughts?

Tim
By three methods we may learn wisdom:
First, by reflection, which is noblest;
second, by immitation, which is easiest;
and third, by experience, which is bitterest. -Confucius

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satchmo
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Re: High oil temp and forensic engine investigation

Post by satchmo » Tue Jun 19, 2012 6:34 pm

SlowLane wrote:Tim, if you have the time and inclination, can I suggest an experiment?

Before you dig into the motor and replace the cooler and its gasket, do a quick oil change to 10W30 and see if the high temperature problem persists. Then do the oil cooler swap / gasket install and see how much of an improvement you get.
Too late. New oil cooler is already installed. I haven't put everything back together yet (gotta fab those little swinging doors at the bottom of the fan shroud, cut out some gaskets, paint some tin, find some brackets, etc, etc). Maybe I will do the experiment you suggest in reverse since I already did the oil cooler and gasket.

The old oil cooler wasn't too bad, but the seals were definitely leaking. The oil pressure valve looked okay. It moves in its bore without binding. Lots of gunk noted in the sump. Someone had been using RTV to seal the valve cover gaskets and there was a fair amount of it caught in the strainer. Note to everyone: Do Not Use RTV on the valve cover gasket. I hope to have the bus back on the road this weekend.

Can anyone tell me if VW switched from using those 'cheese head' slotted screws to using hex head bolts for all the tin at some point? This bus has bolts everywhere there was a screw on my 73 bus.

Tim
By three methods we may learn wisdom:
First, by reflection, which is noblest;
second, by immitation, which is easiest;
and third, by experience, which is bitterest. -Confucius

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SlowLane
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Re: High oil temp and forensic engine investigation

Post by SlowLane » Tue Jun 19, 2012 7:08 pm

This bus had A/C at one time. I think maybe that bashed in heat tube is related to the removed A/C. Thoughts?
I think you hit the nail on the head there. That area is pretty much the only place you could mount an A/C compressor.

My '81 engine has "cheese-head" screws in most places. I don't think VW ever used all hex-head bolts for the tin.
'81 Canadian Westfalia (2.0L, manual), now Californiated

"They say a little knowledge is a dangerous thing, but it is not one half so bad as a lot of ignorance."
- Terry Pratchett

reluctantartist
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Re: High oil temp and forensic engine investigation

Post by reluctantartist » Fri Jun 22, 2012 8:07 pm

It sounds like the oil cooler was plugged up. But fixing the air seal will be an added benifit. I do not agree with the lighter weight oil theory. The owner's manual states to use 20w50 in the summer. And if it is constantly warm above 85 to even use 40w.
82 Westy

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satchmo
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Re: High oil temp and forensic engine investigation

Post by satchmo » Fri Jun 22, 2012 9:15 pm

Got the new oil cooler installed after cleaning up the seal seats. Gasket at the tins replaced too. I filled it with 20W50 oil and will do some test drives this weekend. I hope the oil temp stays under 230 for extended highway trips.

Here are pics of the oil cooler mounting and the oil cooler. No wonder it was leaking.

Image

Image

New oil cooler in place.

Image

Image

Tim
By three methods we may learn wisdom:
First, by reflection, which is noblest;
second, by immitation, which is easiest;
and third, by experience, which is bitterest. -Confucius

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Amskeptic
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Re: High oil temp and forensic engine investigation

Post by Amskeptic » Sat Jun 23, 2012 9:52 am

satchmo wrote:Got the new oil cooler installed after cleaning up the seal seats. Gasket at the tins replaced too. I filled it with 20W50 oil and will do some test drives this weekend. I hope the oil temp stays under 230 for extended highway trips.
Tim, when I did those oil temperature tests with RandyInMaine's vdo oil temp gauges, it was about as hot as its been around here lately, 100's.
I had oil temps in the 230-240* range, spiking to 265* when the engine was shut off to gas up and there was no cooling at the crankcase fins. Once back on the road, the oil temps would drop back to the 230s. I would not worry about 230s oil temps when it is hot outside.
The same Type 4 engine and oil sensor also showed me oil temps that would not break 140-150* when temperatures dropped into the high 30s in Texas later in the itinerary.

I hope your new cooler solves the high oil temps at 70* ambients.

Yes, solid lifter engines had the #1 pushrod located oil control valve that no longer needed to dump high oil pressures with the introduction of hydraulic lifter engines.

I have seen those heat tubes squished with the big York compressors.
Colin
BobD - 78 Bus . . . 112,730 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles

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Hippie
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Re: High oil temp and forensic engine investigation

Post by Hippie » Sun Jun 24, 2012 5:27 pm

Most motor oil doesn't begin to break down and carbonize until at least 250º F. I wouldn't worry about 230 either, if it's hot out. You can easily run 210-220º oil even in a water cooled engine in the summer on the highway--Which is actually kind of good because it evaporates off unwanted moisture faster. 250F at 80 outside temp. like you had before is too hot
Just 2 cents worth from the lube geek.
Image

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satchmo
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Re: High oil temp and forensic engine investigation

Post by satchmo » Mon Jun 25, 2012 8:43 pm

Okay, back on the road. 20W50 oil in the crankcase filled to the top line. Slight uphill on the freeway toward Cajon pass, going about 60-65 mph or 3400 rpm, oil temps are 230* and pressure is 38-42 psi. CHTs are 350-410*. Ambient temp again is about 70.

This is better, but not quite where I want it. I have also discovered a very high idle condition when the engine is this warm - about 1600 rpm. I assume this is related to a vacuum leak someplace that worsens with heat, so today I spent my time testing every connection. I think I have it fixed, but now the AFM tune is fubar (mixture screw was only one half turn out from the bottom) and I need to start at square one to get the engine back in spec. I have yet to open the AFM on this bus so it will be interesting to see what is up. I know it is on the lean side since I took the plugs out when I did the oil cooler and they were quite white.

Thanks for your help/suggestions.

Tim
By three methods we may learn wisdom:
First, by reflection, which is noblest;
second, by immitation, which is easiest;
and third, by experience, which is bitterest. -Confucius

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Amskeptic
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Re: High oil temp and forensic engine investigation

Post by Amskeptic » Wed Jun 27, 2012 6:30 am

satchmo wrote:very high idle condition when the engine is this warm
I know it is on the lean side since plugs were quite white.
See for yourself how the CHTs respond quickly to the mixture at speed.

Your base point is full load at maximum torque (55 mph in 4th).
I have found that 11.8:1 on the LM-1 gives me the best cool CHTs and not too horrible fuel economy.
Wiper adjustment is the one for this, then spring is used to lean out the idle/slow speed.

I seriously have to rewrite the AFM adjustment write-up.
Colin
BobD - 78 Bus . . . 112,730 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles

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drober23
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Re: High oil temp and forensic engine investigation

Post by drober23 » Sun Jul 09, 2017 5:35 am

Hey Satchmo,

Dragging up an old post. Did you ever resolve this?

I'm getting this behavior on my bus after I put it back into service this year. Had the heads off, and installed a timesert. The big change was to swap out an extractor style exhaust with a stock muffler ('78 Type IV FI). CHTs seem to be behaving ok (down from the last post on my itinerary thread). But the oil temp climbs into the 230s within about 15 minutes of highway driving.

In the past, I would be 215 - 220 unless I was really pushing it and it was really hot outside. Now I get 230s when it is 70° F outside.

A couple extra notes:

I do have a rough cold idle (Raby Camper Special), and a higher idle when warm like you had as well.

When Colin was here, we blocked off the brake booster. I corrected a vacuum leak at the booster end and reconnected it. The booster works great, and when I pump the brakes at idle there is no change in engine behavior.
DJ

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(plus more busses than sense)

In a time of chimpanzees I was a monkey

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satchmo
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Re: High oil temp and forensic engine investigation

Post by satchmo » Sun Jul 09, 2017 6:41 am

My memory is foggy on this but I must have found the oil temps acceptable since I dove that bus quite a bit after replacing the oil cooler.

You should check that your thermostat and flaps are operating correctly if you haven't done so already. If there is any question about this, try a run with the thermostat disconnected and flaps open. See what happens (it should take longer to reach normal operating temp).

Satchmo
By three methods we may learn wisdom:
First, by reflection, which is noblest;
second, by immitation, which is easiest;
and third, by experience, which is bitterest. -Confucius

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drober23
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Re: High oil temp and forensic engine investigation

Post by drober23 » Sun Jul 09, 2017 10:08 am

Thanks for the reply!

I disconnected the t-stat cable and drove a bit last night. Took longer to warm up, but once it did I got the same behavior. That is what made me start searching. :-(
DJ

'75 Westfalia, '79 Deluxe
(plus more busses than sense)

In a time of chimpanzees I was a monkey

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SlowLane
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Re: High oil temp and forensic engine investigation

Post by SlowLane » Sun Jul 09, 2017 12:52 pm

Just a theory, but maybe the factory exhaust is not providing as free-flowing a path for the air coming out of the bottom of your oil cooler as the extractor did. Do you have a functional oil cooler gasket? (actually it's more of a short air guide than a gasket.)

It's funny, but my engine struggles to get the oil temp above 200, except on very hot days (like today, expected to hit 101). Could be that my sensor location in the oil drain hole has something to do with it, or maybe the black-painted pushrod tubes help.

We should also keep in mind that VDO gauges are hardly precision instruments, and comparing the results from one person's installation to results from another's without any sort of common calibration is pretty futile.
With that in mind, I should start thinking about how to plumb a RTD sensor into a locatio that would give the most reliable results...
'81 Canadian Westfalia (2.0L, manual), now Californiated

"They say a little knowledge is a dangerous thing, but it is not one half so bad as a lot of ignorance."
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drober23
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Re: High oil temp and forensic engine investigation

Post by drober23 » Sun Jul 09, 2017 1:24 pm

Slowlane, this is what I suspect but I want to check everything else before jumping to this conclusion. Oil cooler gasket was intact upon install and seems in place.

The oil temp sender is: SEN-04-3 - Oil Temperature Sender from Dakota Digital, tied to one of their Odyssey gauges. The temp is taken at the bottom of the taco plate. I know DD CHT gauges are considered better, but not sure about the oil temp senders. The CHT is about the same after the swap, but the oil temp is higher.
DJ

'75 Westfalia, '79 Deluxe
(plus more busses than sense)

In a time of chimpanzees I was a monkey

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Amskeptic
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Re: High oil temp and forensic engine investigation

Post by Amskeptic » Mon Jul 10, 2017 6:51 am

drober23 wrote:
Sun Jul 09, 2017 1:24 pm
Slowlane, this is what I suspect but I want to check everything else before jumping to this conclusion. Oil cooler gasket was intact upon install and seems in place.

The oil temp sender is: SEN-04-3 - Oil Temperature Sender from Dakota Digital, tied to one of their Odyssey gauges. The temp is taken at the bottom of the taco plate. I know DD CHT gauges are considered better, but not sure about the oil temp senders. The CHT is about the same after the swap, but the oil temp is higher.


Try to get a laser thermometer reading as a comparison on the left rear diagonal corner of the case after everything is warmed up. 230* bothers me not in the slightest.
Colin
BobD - 78 Bus . . . 112,730 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles

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