jlw@ariel.UUCP (02/11/84)
We have a Volvo Turbo and Volvo also recommends an oil change interval
of half that of the non-turbo cars. The real reason to change the oil
so often in a turbo car is that the turbo is lubricated with engine oil.
The turbo is a super precision machine. It cannot stand the amount
of dirt and engine blow-by that the engine itself can. All factory turbo
engines that I know about come with an engine oil cooler.
Some tips from the Volvo service manual:
"IMPORTANT!
Satisfactory lubrication is essential for the durability of the turbo-
compressor. It is lubricated by engine oil pressure. There are two important
rules to observe when driving a turbo-compressor equipped engine:
- Let engine idle after start.
This will provide initial lubrication. Do not race engine immediately
after start.
- Let engine return or drop to idle speed before shut-off.
If the engine is shut off while running at high rpm, the turbo-compressor
will run for a long time. This will harm the turbo-compressor as
the engine does not provide continued lubrication after stopping.
Idling before shut-off will also reduce turbine temperatures."
We purchased the complete set of manuals for our car for $66 and they
are certainly worth the price. Here are some other turbo tips from
the book. Some are obvious when you think of them.
- Change oil >and< filter at twice the interval of the non-turbo cars.
3750miles for us. Use oil meeting Volvo specs. (sf-cc)
- Never use sealing compound when repairing engine.
It can get into engine lubricating system and clog oil
passages in turbo-compressor.
- Quick check of turbo-compressor. Switch off engine and at the
same time listen to t-c. With engine at idle, t-c will normally
coast down in 15-20 secs. If engine RPM is high, oil temp. high-
and consequently viscosity and internal friction low-t-c might rotate
1-2 min. after engine has stopped.
if not:
Disconnect inlet hose at compressor housing.
Check that:
- Compressor wheel rotates freely.
- Axial and radial clearances feel normal.
- Compressor wheel does not scrape against compressor housing
when wheel is pushed radially or pulled axially.
(not recommended for the faint of heart. Wear gloves; that sucker is
hot. In fact don't disconnect anything if you don't know
what you're doing; go to a good repair shop. )
- Exhaust extraction. This applies to cars attached to an exhaust
extractor in a shop. If very high exhaust extraction vacuum is used
there is the chance that oil will be drawn into the exhaust system past
the turbo-charger gaskets. This would cause the sound deadening
material in the exhaust system to be soaked in oil, and cause blue
exhaust smoke to be emitted from the exhaust for a long time.
Such a condition could be misinterpreted as turbo inner oil
leakage and could result in unnecessary repairs. Very powerful
exhaust gas extraction systems can also lead to incorrect results
when checking/adjusting the CO level.
TO AVOID THESE POTENTIAL SITUATIONS USE AN EXTRACTOR HOSE WHICH DOES
NOT CREATE A SEALED SYSTEM.
- Turbo Engine Cooling. The heat generated by a turbo engine is higher than
that by a non-turbo engine. Good air flow through the radiator and oil
cooler is therefore essential to obtain effective cooling.
Auxiliary lamps mounted in or in front of the grille will restrict
the air flow and reduce the cooling ability.
Auxiliary lamps should therefore be mounted in or in front of the
spoiler (air dam) on either side of the air intake.
When radiator covers are used, it is important to keep a check on
the coolant temperature and take care not to drive long distances
at high coolant temperatures. (this last is for our faithful
readership in International Falls :-) )
Woooooooooooosh
Joseph L. Wood, III
AT&T Information Systems
Laboratories, Holmdel
(201) 834-3759
ariel!jlw