2.1L Rod Bearing Failures
By Stuart MacMillan
Hello to all of you high mileage 2.1 owners, I hope to do the same
with my new engine, but I can't stress enough the need for an oil
These engines can, and probably will, run strong right up to the time of
disaster, giving you no warning of immanent catastrophic failure if you
don't know the status of your oil pressure! This engine works very hard to
push our nearly two ton rigs around, and
150,000 miles is still the recommended point to rebuild the engine. Once a rod
bearing starts to go, it goes fast (3000 miles!), and without warning (except oil pressure).
This failure is known as "spinning a bearing". I knew I was pushing it, and I pushed too far.
Ignorance is not bliss with these engines!
1990 used engine, 140,000 miles at failure, heads done at 90,000.
Compression: 132-136 psi.
High volume oil pump.
Acceptable oil consumption (1 qt./1500 miles.
Ran perfectly and was very strong, no smoke, no noises, not even valve lifters.
Cruised effortlessly for 3000 miles in six days on last trip, mostly at 75 mph in 85-98 degree temps
Cooling system perfect, 20w-50 Castrol, factory filters.
OIL PRESSURE: 8 psi at idle, 24 psi cruising when installed at 130,000
miles. Over the next 10,000 miles pressure steadily dropped to 4 psi
idle, 12-15 psi cruising. At the end of the 3000 mile trip idle
pressure was zero (red light came on), cruising 8 psi. Blew up at 65
mph just 65 miles from home, still running strong!
Note: Click on thumbnails for expanded images!
When I disassembled the poor 2.1 engine I destroyed in August 2000, it
turned out that rod failure due to a spun rod bearing was the cause of the destruction. This is very
common on air-cooled VW engines, and also on the 2.1 wasserboxer. It is much less common on the 1.9 engine.
As discussed in detail below, the heat generated by a spun bearing causes the bolt to expand, soften and
either break or lose the nut.
In my case the nut loosened and came off, dropping the bolt which
was thrust up through the top of the case by the crank counterweights
where it was embedded.
After that #4 got hit by some shrapnel from the broken
rod, and the cylinder fractured, taking out half the cam along with it and
knocking two more holes in the top of the case and flooding the case with coolant. The resulting
oil/coolant emulsion was then sprayed all over the engine compartment and the freeway behind me.
It took me all day just to clean things up in preparation for a
I took what was left of my 2.1 to my rebuilder, Jerry at Northwest
Connecting Rod, and after close examination we determined that I had
"spun a bearing". This means that the rod bearing shell literally wore
away, leaving steel on steel, not a good thing. According to Jerry, at
high speeds this will generate tremendous heat, even to the point of the
metal becoming red hot with sparks flying off. The heat then will
either cause the bolts to stretch, nuts to loosen or the rod or bolt to
break, leading to catastrophic breakdown, which ever comes first. And,
indeed, the parts of the rod big end I recovered were "blued" from extreme heat!
These rods are worked hard, and the big end tends to go oval as they get up in miles.
This leads to the viscious cycle of increased rod bearing wear causing lower oil pressure -
which leads to increased bearing wear - ad infinitum. This means scrupulous
attention to maintenance coupled with careful oil pressure monitoring is
the key to longevity for this engine, just as it is for any other.
So, I cannot stress this enough: For those of you that have a
2.1 with more than 100,000 miles on it (the consensus is these engines
are good for between 125,000 and 150,000 miles) I strongly recommend
that you do two things:
1: Install an oil pressure gauge!!! This will tell you more than
anything else about the condition of the bearings in your engine, and
can help you avoid catastrophic failure. If your engine is between 100,000
and 150,000 miles, install the gauge to make an assessment of the
bearing condition, and then monitor pressure trends if things are within
limits. If you are over 150,000 miles, you can do the same, and watch for the
tell-tale signs of pressure dropping on long hill climbs (bearings are heating up)
and oil pressure below 4 psi at idle when hot.
2: Start a savings plan for that rebuild BEFORE 150,000 miles. When
you rebuild the engine, have the rods rebushed and the big ends resized to get them
round again, and make sure that the "stretch to torque" rod bolts are not used in
the rebuild, substitute the conventional 1.9 engine rod bolts as they are simply more reliable.
Rebuildable 2.1 cores are getting scarce for this reason. If you
destroy yours it not only will be difficult to find another engine, but
it will cost you the core charge as well, at least another $500 to over $1000.
My new 2.1 engine with high volume Mahle oil pump runs 12 psi idle, 40-45 psi
cruising at 65 mph, depending on temp. I have also installed the
Trasko oil filter system, although I will continue to change the oil every 5000
miles. Having worked in the micro filtration business (Millipore Corp)
their system of combining a large depth-type filter and a mircon
filtration screen makes sense to me. I'll keep
you posted on this, I am installing them on all my cars.
Update on the Trasko filter.
I am impressed with this unit. I tested it out on my daughterís í82 Audi. This poor car has
170,000 hard miles on its 1.6 l engine, and not such good maintenance. After 1000 miles I
removed the cartridge and was amazed at the amount of fine, copper filings were trapped between
the layers of the roll of filter paper. Not to mention the large amount of carbon and crude
caught in the screen. Her previous filter may well have been clogged and bypassed this engine
was so dirty. I donít think any other type of filter could have worked in this application.
We unloaded this car very quickly afterward!
After 5000 miles in the Vanagon the oil was still quite clear and light colored, and the filter
element black with the minute carbon particles it filtered out. I will go with Red Line synthetic
20w-50 oil now for 10,000 miles between changes as Trasko recommends. Iíll test the oil at 5000
miles to be sure it is up to snuff.
Please stop back soon!