Permatex RTV and O2 sensors
10-20-2008, 08:20 PM
#1
Burning Brakes
Thread Starter
Join Date: Sep 2006
Location: Myrtle Beach, South Carolina
Posts: 1,203
Likes: 0
Received 0 Likes
on
0 Posts
Permatex RTV and O2 sensors
I have used Permatex High-Temp RTV Silicon gasket maker #26B on the gasket at the throttle body to intake manifold and I may have pulled the fuel pump fuse and cranked the engine over before it cured. I don't remember how close together these two things were done...
Nowhere on the label does it say "sensor safe"
Could this have exposed the O2 sensor to enough fumes to ruin it?
How about if I didn't turn the engine over, is using it in that location going to expose the O2 sensor to the point it could be ruined with the engine running normally?
Does the danger to sensors come only during curing or at anytime?
Nowhere on the label does it say "sensor safe"
Could this have exposed the O2 sensor to enough fumes to ruin it?
How about if I didn't turn the engine over, is using it in that location going to expose the O2 sensor to the point it could be ruined with the engine running normally?
Does the danger to sensors come only during curing or at anytime?
10-20-2008, 10:20 PM
#4
Captain Obvious
Super User
Super User
My interpretation is that the sealant (not the curing fumes) gets into the combustion chanber, the burnt fumes will coat/damage/poison the O2 sensor.
Edit: had a typo in there.
Last edited by Imo000; 10-20-2008 at 11:00 PM.
10-20-2008, 10:27 PM
#5
Administrator - "Tyson"
Lifetime Rennlist
Member
Lifetime Rennlist
Member
Another source of sensor contamination can come from silicone poisoning. If somebody used the wrong kind of silicon sealer to seal up a leaky rocker box cover or manifold gasket, silicone can find its way into the engine and foul the sensor. Silicates, which are used as corrosion inhibitors in antifreeze, can also cause the same kind of poisoning. Sources here might include a leaky head gasket or racks in the combustion chamber. Silicone deposits on the sensor tip will have a shiny white to grainy light gray appearance.
10-20-2008, 11:25 PM
#7
Drifting
Oxygen sensors are a lot more tolerant to nasty things than most people would lead you to believe. Testing on LSU 4.2 sensors showed they would function in leaded race gas exhaust for several thousand hours.
Trending Topics
10-21-2008, 09:51 AM
#8
Captain Obvious
Super User
Super User
well..... leaded gas destroys catalytics and not the O2. At least that's how I know.
10-21-2008, 11:08 AM
#9
Addict
Rennlist
Site Sponsor
Rennlist
Site Sponsor
Join Date: Jan 2003
Location: Green Bay Wisconsin
Posts: 951
Likes: 0
Received 0 Likes
on
0 Posts
From a Google search (this is one of many saying the same thing).
I was hoping to find something that referenced fully cured silicone but no luck.
What will damage my O2 sensor?
Home or professional auto repairs that have used silicone gasket
sealer that is not specifically labeled "Oxygen sensor safe",
"Sensor safe", or something similar, if used in an area that
is connected to the crankcase. This includes valve covers, oil
pan, or nearly any other gasket or seal that controls engine oil.
Leaded fuel will ruin the O2 sensor in a short time. If a car is
running rich over a long period, the sensor may become plugged up
or even destroyed. Just shorting out the sensor output wire will
not usually hurt the sensor. This simply grounds the output
voltage to zero. Once the wiring is repaired, the circuit
operates normally. Undercoating, antifreeze or oil on the
*outside* surface of the sensor can kill it.
This is from a 944 board and mentions the sensor getting the reference air through the signal wire.
This is not commonly known by many in the automotive world so those of you that soldered your signal wire might want to cut out the soldered part and use a crimp connector.
If you don't believe me, cut a section of signal wire off an o2 sensor and see you you can blow bubbles in your beer through it.
BOSCH "Universal Replacement" Part Numbers
BOSCH short P/N Description
Wires
Heated
BOSCH long P/N Replace
11027 Universal Replacement without connector
924 80-82, 924 Turbo 80-82, 928 80-82, 944 83-85.1 1 No
0 258 001 027 30,000 mi
13913 Universal Replacement without Connector (must be spliced to factory connectors)
924S, 944 85.5-89, 944S, 944S2, 944 Turbo, 968 3 Yes
0 258 003 913 60,000 mi
15726 Universal Replacement with Connector Kit (replaces stock connectors)
924S, 944 85.5-89, 944S, 944S2, 944 Turbo, 968 3 Yes
0 258 005 726 60,000 mi
Tools
Appropriate Size Open End Wrench (most take a 15/16" or 24mm)
Crimp Type Wire Connectors
Wire Connectors
General Installation Tips
If you are replacing the O2 Sensor with a universal replacement sensor, you'll have to splice the factory connector plug onto the new sensor. Or if you've order a sensor kit which comes with connectors, you'll have to install the connectors which come with the kit onto the new sensor wires. DO NOT solder the connectors onto the wires. They must be crimped on for the O2 sensor to work correctly. For the sensor to work correctly, it must draw clean air down to the sensor through the air gaps in the stranded wire. If you solder the wires, the solder will fill the air gaps in the wire and the sensor will not work correctly.
Do not use any silicon based chemicals that could become exposed to the O2 sensor. Silicon will contaminate the sensor and it will quit working. Many RTV sealants, gasoline additives, and anti-seize compounds contain silicon so, check the label before you use it.
I was hoping to find something that referenced fully cured silicone but no luck.
What will damage my O2 sensor?
Home or professional auto repairs that have used silicone gasket
sealer that is not specifically labeled "Oxygen sensor safe",
"Sensor safe", or something similar, if used in an area that
is connected to the crankcase. This includes valve covers, oil
pan, or nearly any other gasket or seal that controls engine oil.
Leaded fuel will ruin the O2 sensor in a short time. If a car is
running rich over a long period, the sensor may become plugged up
or even destroyed. Just shorting out the sensor output wire will
not usually hurt the sensor. This simply grounds the output
voltage to zero. Once the wiring is repaired, the circuit
operates normally. Undercoating, antifreeze or oil on the
*outside* surface of the sensor can kill it.
This is from a 944 board and mentions the sensor getting the reference air through the signal wire.
This is not commonly known by many in the automotive world so those of you that soldered your signal wire might want to cut out the soldered part and use a crimp connector.
If you don't believe me, cut a section of signal wire off an o2 sensor and see you you can blow bubbles in your beer through it.
BOSCH "Universal Replacement" Part Numbers
BOSCH short P/N Description
Wires
Heated
BOSCH long P/N Replace
11027 Universal Replacement without connector
924 80-82, 924 Turbo 80-82, 928 80-82, 944 83-85.1 1 No
0 258 001 027 30,000 mi
13913 Universal Replacement without Connector (must be spliced to factory connectors)
924S, 944 85.5-89, 944S, 944S2, 944 Turbo, 968 3 Yes
0 258 003 913 60,000 mi
15726 Universal Replacement with Connector Kit (replaces stock connectors)
924S, 944 85.5-89, 944S, 944S2, 944 Turbo, 968 3 Yes
0 258 005 726 60,000 mi
Tools
Appropriate Size Open End Wrench (most take a 15/16" or 24mm)
Crimp Type Wire Connectors
Wire Connectors
General Installation Tips
If you are replacing the O2 Sensor with a universal replacement sensor, you'll have to splice the factory connector plug onto the new sensor. Or if you've order a sensor kit which comes with connectors, you'll have to install the connectors which come with the kit onto the new sensor wires. DO NOT solder the connectors onto the wires. They must be crimped on for the O2 sensor to work correctly. For the sensor to work correctly, it must draw clean air down to the sensor through the air gaps in the stranded wire. If you solder the wires, the solder will fill the air gaps in the wire and the sensor will not work correctly.
Do not use any silicon based chemicals that could become exposed to the O2 sensor. Silicon will contaminate the sensor and it will quit working. Many RTV sealants, gasoline additives, and anti-seize compounds contain silicon so, check the label before you use it.
