cmartin2112

Hey guys,
Gotta a quick question... I am rebuilding my motor and am trying to figure out what some of these random holes in the block go belong to... I am pretty sure this one on the right is correct and it belongs to the coolent temp sender unit because it opens up right next to the cooling ports next to the cylinder walls.
The one on the left I am still unsure about. These holes are tapped and they are located right under the intake and exhaust manifolds.

car5car

Left one is coolant drain plug.

cmartin2112

Now for the next one... I am pretty sure something screwy happened here. I cant find the hole for the oil pressure sending unit.
I can however find a hole that was filled by a galley plug (that my machine shop installed). Its located right above the oil filter adapter (see pic below). Also if this is the hole for the oil pressure sending unit is the joint that I have installed in the left hole on the pic above belong to the pressure sending unit. The reason I ask is because the oil sending unit threads perfectly into that joint.

cmartin2112

Also forgot to mention this is an 89 renix I6 4.0.

cmartin2112

Well the right hole has the thermo sensor installed in it. My head doesnt have a spot for a temp sensor (atleast I dont think). And my thermostat housing just has the water inlet hole and outlet hole no tapped hole for the sensor.

1991Jeep_Man

You're good there. Renix 4.0's didn't have the CTS in the thermostat housing like '91- up models did. They had it in the block where yours is, and the temperature sending unit is near the back of the head.

1991Jeep_Man

Did some research for ya.

Found this pic. If the sending unit threads fine into the hole, then it's likely the spot it belongs in. See the diagram below:



Also, I don't know if it matters, but your CTS and block drain plug might have been switched up:

cmartin2112

Is that the brass post with the threads on it located in the back right corner?

cmartin2112

Great pics. I will pull that oil galley plug out and try to thread the elbow in there hopefully they didnt re-tapp the hole to fit a larger plug.
The issue with the other hole is that the sensor wouldnt thread in there so maybe its set up right but I just need to locate a freeze plug/oil galley plug for that spot.

cmartin2112

Ok wait!!! So I just found this pic by googling renix 4.0 and going in the images tab (I know I probably should have checked this before opening a new thread). So it looks like the temp sensor does go towards the front of the motor but I cant tell what the other hole is filled with... It kinda looks like a sensor. But who knows.....

thakmfb

the other hole is just a block drain and should just have a galley plug in it with some teflon tape or something of the sorts. The little adapter you have installed on the front of the block in first picture i believe goes to the port by your oil filter adapter. Most I have seen have a 90* fitting on them and then the oil pressure switch threads into the adapter. As far as which hole the sensor goes in. I am not sure. Look at your wiring harness and see if the plug for the sensor is towards the front or the back. And that should tell you. But judging from the picture out of the service manual someone posted it should be on the front of the block. Otherwise I dont think it should matter too much as long as its in the cooling jacket

cmartin2112

Ok great! I acctually pulled out the 90* fitting and set it aside for when I pull out the oil galley plug that the machine shop installed on top of the oil filter adapter. The coolent temp sensor does thread into the front location. Do you know where I could find one of those plugs? I tried looking around with no luck...

By the way I like your signature! I am looking to get my conceal carry hopefully by Septmeber.

thakmfb

Well if the 90* fitting fit in the block i would surmise that the plug the machine shop put in the oil galley should fit. Just put some teflon tape on it. I have always likes using a liquid thread sealant (liquid teflon tape) I feel it gets in the threads a little better. Good luck!

freegdr

swith the cts and drain because the drains gonna be a ***** to get at with the motor mount in thr front in the way, oil plug a different place to mount a oil pressure gauge.

cruiser54

CTS goes in the forward hole on the driver's side of the block. A plug goes into the rear hole on that side. The angled brass fitting goes in the passenger side of the block near the oil filter for the oil pressure sender. Gauge temp sending unit goes on the rear of the head driver's side.