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Tech / General EngineIs your car making a strange sound or won't start? Thinking of adding power with a new combination? Need other technical information or engine specific advice? Don't see another board for your problem? Post it here!
I was trying to replace my fan temp switch (bw 6 and 8 cylinder) and part of it broke off inside the block. It's seems loose loose sitting above the threads but too large too fall through the hole. How the heck can I get it out?
Last edited by 89 formula TPI; May 16, 2015 at 01:58 PM.
Nothing is in there other that rust.
Just screw the knock sensor back in (with sealant) and get the sensor out of the head (passenger side head above the spark plugs between 6/8)
thats a great idea...will the knock sensor still work? there is enough of the treads left it looks like
I do not see any threads missing on the knock sensor!! If you are concerned about it, a new knock sensor is under $40.00. Just be sure to properly torque it.
It's just gunk in the bottom of the block, I doubt anything is broke off in there. That sensor looks fine to me, it's just dirty. Every once in a while it's good to take the radiator cap off, then remove the knock sensor and block plug (just opposite the knock sensor on the drivers side) and flush the block with the motor running and a hose in the radiator. I usually do it in the fall while winterizing. That gunk settles at the bottom, and sometimes even if you pull the block plug and sensor the coolant won't immediately drain. In fact, it usually won't unless it's been cleaned regularly. Take a probe or thin screw driver and carefully pull the crud out, or knock it around and it will drain. If you don't need to do a flush just screw the knock sensor back in and reconnect the connector. The fan switch is higher up between the 6 and 8 cylinders. If you have a bad fan switch, be careful of the connector too. They dry rot from being exposed to the heat from the manifold and can break and short out when you try to unplug them.
Guys thank you so much, I successfully just screwed it back in. I guess it was just gunk in there which I will clean out next time.
Any tips for getting that fan switch out? It's in such a tight spot.
Also that switch controls the auxiliary fan, not the primary,right?
Yes, the secondary fan switch is there between 6 & 8. Im assuming you have tpi? The primary fan is controlled by the ecm using the coolant temp sensor. That's usually screwed into the front of the intake beneath the TB. It has an electrical connector with two wires. Your secondary fan switch is "dumb", it doesn't communicate with the Ecm, just comes on when a certain temp is reached. Therefore, it usually has a single wire connector.
Last edited by TheExaminer; May 17, 2015 at 07:56 AM.
Ok Thank you. For sime reason now My auxiliary fan runs all the time, even with the aux fan relay unplugged, the fan switch unplugged, and the AC off! I have the wiring diagram and was trying to see if someone rigged it to run all the time but didn't see any signs of it.
What's strange is for the last 3 months I couldn't get it to run ever, even when the car was overheating. And yesterday it just decided to run constantly. Any idea what the cause could be?
So I was testing my primary fan...I grounded the grn/wht wire and it kicked on with the ign on but not running. I started the car and Now i have the same problem with the primary where it is running constantly as soon as car turns on. So now I have both fans spinning constantly from the moment the car is on. when I unplugged the primary relay the main fan turned off so I think something funky is up with it so I am going to change it out.
Unplugging the aux relay didn't stop the secondary from running
I also hooked up alligator clips to my coolant temp sensor and set my multi meter to continuity and ran the car but it never beeped so I am swapping the CTS as well
My secondary fan ran all the time too, but it turned out the connector was shorted. I replaced it and it doesn't run now. I shorted across at the relay and it kicked on, so I know it works if needed, it just doesn't run constantly now.
so my primary was acting funky bc of the coolant temp sensor (even though the one in there was almost new). i replaced it and now my primary kicks on at 235 and off at 220.
i found out for my secondary the reason it was always spinning was bc they crossed the black and red wire (power) and grounded it so it was always grounded. i undid it and my secondary stayed off. this explains why it was always running even though i unplugged the relay.
i may actually put it back though because the car runs around 225 now but wont overheat. i prefer it to run a little cooler, which was around 190 when the secondary was rigged to stay on.
the only issue is now that the secondary doesn't turn on when the AC is on. i suspect this is the temp fan switch which i have yet to replace.
That's what was making my secondary run too, only it was just plain worn out. Some of the insulation wore off, and it shorted across the connector at the switch itself.
Last edited by TheExaminer; May 17, 2015 at 02:44 PM.
Examiner did you leave it grounded? i feel like with the secondary always on it stays nice and cool around 190...instead of bouncing back and forth around 225-235 when the primary kicks on/off. GM only designed them to run that hot to help with the emissions but i can't imagine thats better for the engine.
No, I just replaced the connector which hopefully returned it to stock condition. IMO 190 is too cool, especially when these cars came from the factory with a 195 therm. If you never get above 190, the therm won't even open up unless you've put a 160 or 180 in it. Actually around 210-220 is pretty healthy from everything I know. Mine hovers around there when at full temp. A lot of people think the cooler the better, but that's not necessarily so. You have to have a certain amount of heat to burn the condensation out of the oil. Also, running too cool can hurt your gas mileage. And another problem with leaving the fan on all the time is it shortens the fan motor's life, and also makes it take longer for the heater to get warm in the winter. If you're consistently at 235-240 you're running a LITTLE warm, you might look into why. But if you're at 210-220, heck, I'd leave it alone your engine is very happy there!
thats an interesting take. my car definitely seems to drive better when it's cooler. it just is more responsive when it's running cooler, when it heats up the pick up is sluggish and there is a noticable delay from when i hit the gas and when my RPMs rise.
I actually suspect the O2 sensor to be at fault, when i put the car in diagnostic mode, the CEL is supposed to blink once a second in closed loop but it stays out indicating it's running lean.
seems i have more testing to do, thanks for your help regardless!
Hey, I don't know everything, you may be right. I've been thinking about changing my O2 also, just to help get better mileage. I was getting 15-16 or so, but since stage 2 performance chip along with cap, rotor, plug and wire change I'm closer to 20 or more.
wow 20 mpg is great. i would suggest swapping the 02, around me you can pick up a new for for $20 bux which aint bad at all. the problem will be getting it out. i am trying to get out there this before the weekend to do mine. hopefully not to difficult.
No, I just replaced the connector which hopefully returned it to stock condition. IMO 190 is too cool, especially when these cars came from the factory with a 195 therm. If you never get above 190, the therm won't even open up unless you've put a 160 or 180 in it. Actually around 210-220 is pretty healthy from everything I know. Mine hovers around there when at full temp. A lot of people think the cooler the better, but that's not necessarily so. You have to have a certain amount of heat to burn the condensation out of the oil. Also, running too cool can hurt your gas mileage. And another problem with leaving the fan on all the time is it shortens the fan motor's life, and also makes it take longer for the heater to get warm in the winter. If you're consistently at 235-240 you're running a LITTLE warm, you might look into why. But if you're at 210-220, heck, I'd leave it alone your engine is very happy there!
I have never had a small block that liked those temperatures. Even the Vortec 350 in my Express van likes to be in the 180*F range. Any hotter than about 190*F and the PCM starts pulling timing and HP starts falling off.
The stock 195*F thermostat will keep the engine in the 195-200*F range regardless of airflow through the radiator.
I have never had a small block that liked those temperatures. Even the Vortec 350 in my Express van likes to be in the 180*F range. Any hotter than about 190*F and the PCM starts pulling timing and HP starts falling off.
The stock 195*F thermostat will keep the engine in the 195-200*F range regardless of airflow through the radiator.
Ok, thx. Just going on what I've heard before, which could be wrong. Truth be told, now that I think about it, mine is under 200 almost all the time, so this is actually good news.
