temp sending unit location.....

[joe_peters]

That's indicative of everything cooling related, such as water pump, loose belt, crud in the coolant, etc

Absolutely true, but a loose belt also presents by being worse at higher RPMs, and the same with a bad pump, but you are correct that the full system needs to be inspected. :cheers:

 

[MarioWario]

I have a 89 with a coolant temp gauge in the cluster but it doesn't work...
So I got some sunpro gauges and I'm trying to figure out how I can get the temp gauge to work...
can anyone help???

 

[joe_peters]

Electrical or mechanical gauges?

Your temp sending unit is in the rear of the head, driver's side. It is a single wire sensor, so it grounds through the body of the sensor. Too much thread sealer will screw things up.

 

[MarioWario]

Mechanical. Yeah I had a feeling that was it but I wanted to be sure. The instructions say no thread sealer. So I'm guessing I just pull out that sensor n replace it with the bulb sensor and nut thing sunpro provided?

 

[joe_peters]

Mechanical. Yeah I had a feeling that was it but I wanted to be sure. The instructions say no thread sealer. So I'm guessing I just pull out that sensor n replace it with the bulb sensor and nut thing sunpro provided?

Yep, that should do it.

 

[MarioWario]

Hell ya thanks mang

 

[Wolfe]

is there a way to use the sensor on the thermostat to measure the temp. Then -perhaps manual operate the electric fan? I swapped a motor from a tj into my xj and it doesn't have the rear temp hole. So apart from changing heads I dont know a way to have both sensor working. Any ideas?

 

[MrShaft696]

I did the gauge swap as people have mentioned, and you have to swap the sensor that is on the head, right above the spark plugs on the driver side of the motor. Its a small one wire sensor, purple wire, I bought one and broke it installing it, so I pulled like 3 or 4 from the junk yard, because they are so easy to break.

Lucky for me the wiring to the clip over the sensor was bad so I changed the sensor like 5 times before I realized the wiring was bad, but yes thats the sensor to change. Ill take a pic of where it is if you really dont think you have it.

 

[joe_peters]

is there a way to use the sensor on the thermostat to measure the temp. Then -perhaps manual operate the electric fan? I swapped a motor from a tj into my xj and it doesn't have the rear temp hole. So apart from changing heads I dont know a way to have both sensor working. Any ideas?

Year/engine? BASICS are always helpful.

 

[Wolfe]

Year/engine? BASICS are always helpful.

Its a 95 RHDxj classic model but the engine is from a 97 tj Wrangler and doesn't have the hole in the rear of the block to put the sensor.

 

[joe_peters]

Its a 95 RHDxj classic model but the engine is from a 97 tj Wrangler and doesn't have the hole in the rear of the HEAD to put the sensor.

Fixed.

Ok, couple of options:

There is a flat space on the thermostat housing when looking at it from the front. Drill a hole, use a 3/8" NPT tap--DON'T GO TO DEEP--and put the gauge sender in there.

Purchase a heater hose sensor adapter from summitracing.com or jegs.com or Hesco, cut the heater hose and install it.

Pull the block drain plug and install it there. NOTE: some say the hole is already 3/8" NPT, others say it is 5/8"-18. If it is the later you will need an adapter, AutoMeter and other places to acquire it. Remember, when getting adapters they are usually described by what you want to change and what you want it to be. In other words, if the port in the block is 5/8"-18 and you want to put a 3/8" NPT in it, then you want a 5/8"-18 female to 3/8" NPT female adapter.

 

[Wolfe]

yep head sorry. I like the idea of putting it on the thermostat housing I've already purchased the drill and tap as I'd thought of drilling a hole in back of engine block in the stock position but decided against that.
Thanks for the reply i'll keep you posted as to how I get on.

 

[joe_peters]

Good. Just make sure you don't run the tap too deep, NPT is tapered and if you get to deep there won't be enough "bite" to hold the sensor.

Good luck.

 

[ehall]

There is a flat space on the thermostat housing when looking at it from the front. Drill a hole, use a 3/8" NPT tap--DON'T GO TO DEEP--and put the gauge sender in there.

The sender uses 1/8 NPT not 3/8 NPT

Pull the block drain plug and install it there.

That hole should already be 3/8 NPT so should only need 1/8 to 3/8 adapter bung

 

[joe_peters]

That hole should already be 3/8 NPT so should only need 1/8 to 3/8 adapter bung

Had a number of posts lately that swear theirs is 5/8"-18. You have any info on a change year for the block plugs?