Frequently Asked Questions:
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Q: The "Service Engine" amber
lite is turned on my car. I checked the oil & coolant levels. What does this lite mean?
A: The amber light is refered to as "Service Engine", or "Check Engine",
or "MIL" lite. This one lite is probably the most understood item on the modern car! Because this lite is tied to
whether you pass your smog check ornot, it is also a very important lite. This lite is NOT tied to whether
or not you have oil or coolant in the engine. It's more about how much emissions the car is emitting. Anything that will
make the tailpipe emissions (smog) go up, is tied to little amber light. The "Check Engine " or "Service Engine
light" will come on when a sensor that the computer is monitoring is broken, disconnected, or out of range. The lite is also tied to other systems beside the engine; like the transmission
and the ABS/Traction control. Remember, this is a "REPAIR ME" type of lite not a reset lite.
Q: My Northstar engine is overheating.
It runs good, has good power, but overheats on the freeway or going up an incline. I've changed the water pump, the thermostat,
the radiator, but nothing seems to help.
A: The Northstar engine has been hailed as one
of the world's best engine. It's all aluminum engine block & heads provides many advantages over it's steel
block predecessors. Unfortunately, extreme heat is one of the Northstar's enemies. Overheating the engine can damage the
head bolt threads on the block. Once the head bolts loose tension, the head gasket allow combustion chamber gases into
the cooling system. Combustion chamber gases will form air pockets in the cooling system, causing thermostat malfunction
& overheating. The Northstar engine has a constant air purge system for the cooling system, but this is
overwhelmed when the head gaskets/head bolts fail. Under heavy power demands, the head gaskets will allow more gases into
the cooling system than under light power demands, that is why the engine may be O.K. while driving in flat streets, but overheat
very quickly while climbing a steep incline.
Q: My Northstar overheats. Why don't I see water in the oil?
A: The head bolt threads in the block
can fail in many different patterns. There are a total of 20 head bolts (10 per head; 5 in the upper head, 5 in the lower
head). If most of the lower headbolts loose their tension, coolant that surrounds the piston sleeve will leak in the
oil return & end up in the oil pan, where the coolant will mix with the oil. If the upper head bolts loose their tension,
no coolant will mix with the oil, but the engine will overheat, due to air pockets in the coolant system. We've found
that when there is water in the oil, the engine heads & engine block surfaced are warped.
Q: It's been determined that the head
bolts on my Northstar have pulled from the engine block. Does this mean I have to change the engine?
Changing a Northstar engine either used or new is quite an expense. Unless the lower part of the engine is damaged, the engine
block head bolt threads can be drilled out & special (timesert) inserts can be threaded in, making the new head bolt threads
stronger than the original ones! This repair is often more cost effective than replacing the whole engine. Up to now,
GM's insert repair was the only repair on the market. Unfortunately, GM's repair is NOT
always effective! Now, Juan Macias has developed a NEW insert that is many times stronger
than GM's insert repair!
have been installing this insert (NS-Perma-Insert) exclusively at Macias Cadillac with fantastic
Q: I did a complete tune-up on my 90
Cadillac, but it stills runs rough. It feels like it doesn't run on all cylinders. I sometimes see black smoke out of
the exhaust. The car may stall sometimes. A:
There are many items that can make a engine run rough, but one common problem with the 4.9L/4.5L multi-port engines are the
injectors. The factory injectors tend to short out and cause problems with the fuel delivery of the engine. Typically, the
computer drives the fuel system rich (adds more fuel than usual). We have a special fuel injector tester to quickly
and decisively test the injectors on the car. This tester can pinpoint if one injector or all 8 injectors are bad. We
can provide several choices in replacing injectors from new GM factory injectors, to quality remanufactured, to tested used
injectors. Call us for testing your car.
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