Volvo Maintenance Hints for 7xx/9xx - Bill Garland's Nuclear ...

just pulled the small hose from the manifold and left it disconnected: reconnect when done.
● Take a jar (normal size mayo or spaghetti sauce jar) filled with water (this would be just under 3 cups)
● One hand holding throttle open so engine remains in the 3 to 4 thousand rpm range.
● Dipping hose in water over and over approximately once a second for about 1/2 (0.5) second or less,
less often if engine slows significantly, engine will run rough so use throttle to maintain engine speed until
all the water is gone which will take only a couple of minutes more or less.
● Repeat with the 16 oz can of Seafoam Carbon Cleaner or GM Top End Cleaner. NOT recommended:
carburetor cleaner or Berryman's Chemtool.
● Let the engine stall before you run out of cleaner and let it sit for 15 minutes. Then restart and finish with
the Seafoam.
● Remain alert and focused and just don’t let the hose stay in the water/fluid for much more than half a
second at a time and you should be safe. You know you are feeding in too much fluid if the engine speed
drops significantly even though you are trying to maintain it with the throttle.
● Take the car out for a vigorous run at high rpms.
His technique was to dip the hose (with no orifice) in the liquid (only when the engine is running at a mid rev
range) only for a second at the most, but over and over again not letting the engine slow significantly, using up
all the fluid. Next using exact same method with an injector cleaner, Sea Foam Carbon Cleaner (SF16, UPC#:
1881200001) (or GM Top End Cleaner), this time producing plenty of smoke, both black and blue. She survived
I thought to my self. Did not expect any difference in the car but I was wrong. This made a car that felt great feel
much better, pulls stronger, revs smoother, louder exhaust.
Other Ideas. See the Notes in the Engine:Performance Section for more ideas and tips.
Burnt Valves in 740GLE Head with Hydraulic Lifters. [Problem Diagnosis by James Rothe] At about 90k
miles, my 740 GLE started a recurring burnt valve problem. Three times (!) did I have valve(s) replaced before
we found out what the problem was. I should add that throughout my ownership of the car it has burned oil --
slowly, so that you could not see blue smoke -- but as much as one quart per 1000 miles. The previous owner
reports the same. The dealer said that was "within normal limits."
What we finally found out was that early B234 engines, with their "hydraulic valve lifters", had an infrequent
manufacturing defect in which the holes for the valve guides were made ever-so-slightly oval. The problem, as
it was reported to me, is that the hole in the head itself, into which the guides are pressed, was oval. It's an
infrequent defect that reportedly occurs in both 740 and 850 heads with hydraulic lifters. That's a very different
situation from having defective valve guides or seals.This is not exactly a perfect fit for a circular valve guide, so
it allowed a small amount of oil to seep onto the valve. The speculation is that this burned onto the valve,
caking up the valve with carbon deposits, and prevented the valve from properly seating. Without proper
contact with the cylinder head, the valve could not transfer its heat to the head and it burned.
My mechanic, a family friend who works as a mechanic at a Volvo dealership very nearby Volvo's North
American headquarters in Rockleigh NJ, found out that Volvo is aware of this problem in the 89 740 GLE and in
other Volvo engines with hydraulic lifters, like the 850 series, but that "the problem is not statistically significant
enough to justify a [costly] recall campaign." Or so says Volvo Customer Relations.
We didn't find out about this manufacturing defect until after two top-end rebuilds, by which time the car had
over 120,000 miles on it. Needless to say, Volvo declined my request for "goodwill" service. Part of their
argument was that "this problem usually shows up within the first 10,000 miles." My response was "perhaps,
but if it's been going through oil for all of it's life, and that condition stops after the valve guide hole is corrected,
doesn't it make sense that this oil control problem at the valve guide would adversely affect the valve, just like
your 'statistically insignificant' manufacturing defect is known to do?" I also added that I was the first owner to
do extensive hi-speed highway mileage with the car. The previous owner may have never got the head as hot
as I do every day. "It didn't matter."