Is there a coolant temp sensor on the back of the block (b17a)? I got my block back from golden eagle and I'm putting it back together and am left with a big threaded hole that looks to be coolant related. I have no sensors or plugs that would go there. I'm guessing it was orignally plugged and they took it out when sleeving the block and didn't put it back. Any thoughts?

 

thermostat housing???? yeah there is a coolant sensor there, it wasnt plugged ask for your sensor back.

 

No, it is on the block directly. Looking at the block from behind, it is just to the left of the oil filter and oil pressure switch.

 

my bad - ohhh he meant that one....

 

it might go to the tb heater!!??

 

The thing is it's threaded, and I have no sensors (or wiring harnesses going to a sensor) or anything else that is threaded to go in there. I think if it was a plug I wouldn't have taken it off when I sent the block to golden eagle, and they might have taken it off and forgot to put it back on. Right now the sensors on the back side of the block are oi pressure, oil temp, and knock. This hole is right next to the oil pressure and oil temp sensors, and seems to enter a coolant channel.

 

Any other ideas?

 

I don't know jack about b motors but I know the d blocks have a sensor in the exact location you describe that is used to turn the cooling fan on and off. They're connected by a single wire that pushes onto the end of the sensor.

 

on the 91 and older b16 and ls blocks there is a green plug with two nipples.... i believe it's the fan switch, might be wrong... your coolant temperature sensor is on the head by the coolant line....

 

Oops, yep, that fan sensor on the back has 2 wires, its the oil sensor next to it that only has one.

 

i'm thinking it could be the thermoswitch.. look for two wires running from the main under-hood fuse/relay box to that general area.. at least on my 99 Si, that's how it's wired up. The thermoswitch just has two leads and they activate a relay in that box.

-Xerxes

 

its the oil temperature sensor. its a sensor that will turn on the fan when a certain oil temperature is reached.

 

Huh? Uh, no such animal.

 

Well, I'm not versed on B17 blocks too well, but...

If you have a thermo switch in your thermostat housing (uses a round 2 pin connector), then the hole in the back of the block had a threaded plug in it. If you do not have the switch in the thermostat housing, then the switch should have been located in that hole. That switch connects via two leads with bullet connectors. Make sense?

 

Thank you DSF, that's what I needed to hear. I do have a temp sensor in the thermostat housing. That confirms Golden Eagle most likely took the plug out and forgot to put it back. Any idea what size that plug might have been? Or more importantly, what kind of thread pattern it is? I've got a water temp sensor for a new gauge that I would like to put there, but the sensor threads into a 1/8" NPT hole, and this is much bigger.

 

ttt

 

I'm actually in the same boat. The plug on the back of my B18B is missing. I'm hoping that one of the plugs off of one of my spare SOHC engines fits. But sorry, I don't know the thread pitch.

FYI: I taped my Autometer water temp. sending unit into the upper radiator neck going into the head. I figured the ecu reads post radiator coolant temps. so I will too

 

If you find out what size it is can you let me know? Or even a general idea of the size - my block is back in the car so it is getting harder for me to check it.

 

It is definately the oil temp switch. Older integras used it to control when the radiator fans came on.

When we swapped jeremy's B18A out for a '97 B18B, there was no place to plug the sensor into, so we left it disconnected. Now his radiator fans come on at random times for no reason =P Hehe.

Dustin

 

I do have any oil temp switch, the hole I'm having a problem with is right next to it. It is defintately a coolant channel that my hole is at.

 

On the second gen integra blocks have both an oil temp switch and oil pressure switch on the back near the oil filter.

 

 

Yeah, I think on the older integras the water temp switch that would normally be in the thermostat housing is on the back of the block. We had to add wire and extend the plug so that we could use the sender on the housing...

 

I do have it on the thermostat housing as well, although my 92 service manual shows it being on the back of the block. I don't have any wiring harness connectors left over so I'm 99% sure that it was just a plug there before. Now I just need to figure out what size it is so that I can plug it up or adapt it to use my 1/8" NPT water temp gauge sensor.