garretthes

I'm trying to install a mechanical temp sensor on my 5.3 conversion into a 59 Chevy truck. I'm assuming the stock computer needs to see the coolant temp sensor on the drivers side front of the head. Are there any other places to install a sensor? There is a round plug on the pass. side on the back of the head. Not sure if it's an option.

veee8

iTrader: (40)

Yes, you can pull the plug and put it on the passenger side. BUT be prepared to either modify a stock sending unit, or use adapters to get it to work.
I used an Autometer mechanical temp last summer, and it was a pain in the *** and didn't work too well.
The Autometer gauge used a 1/2" probe, the LS1 head uses a 12mm metric thread, I needed 4" worth of adapters and fittings to get it to work, it left the probe way too far from the water jacket, resulting in a way different reading than the PCM. Just so you know.
Now if you use a stock GM style electric sending unit, you can lathe it down to the proper thread.

garretthes

I don't quite understand what you mean by using a stock sending unit? I bought a sunpro mechanical gauge. The best thing that could happen is to be able to use the 58 truck gauge. Is that possible?

bczee

iTrader: (12)

One of the problems is trying to fit a 1/2" threaded sender into the 12mm head is room or clearance of using a 1/2" in the head, Header flange comes very close as may well be the water jacket. Many have drilled and tap to 1/4" or 3/8".. or have used adapter to use a 1/4" sender. I drilled and tapped mine for 3/8" and used autometer electrical sender/gauge.

Some (as veee8) has tried using the 1/2" threaded sender by using adapters. like pipe extensions or other rigged up way, but they end up sticking way out away from the engine and coolant flow. Not a very good idea or as Veee8 said, it doesn't work well.

Some have taken there 1/2" sender and turned it down to 12mm to fit.

Does Sunpro make a electrical gauge/sender to match what you already have ?

Horsepwraddict

iTrader: (12)

you can run a 1/4" tap through the hole in the head without even drilling it. Several people, including myself have done it. Just put a little grease on the tap, go slow and it will be fine....no need for adapter.

jomomma

iTrader: (39)

another option is a fitting that summit sells.its made by flex-a-lite.p/n flx-32082 and 32084. its an inline hose adapter with a bung iin it for a sending unit. it comes with adapters. it rus inline with the radiator hose.

garretthes

I'm not sure I have enough clearance to tap.

1987earthquake

iTrader: (9)

How accurate would the reading be this way?

jomomma

iTrader: (39)

you should get the same reading as you would from the heads.

dsrour

If you have a first design pump this is a good location. This is using a stock (c2)vette sender. Drill hole, tap w/ 1/2 inch NPT.(same size as heater hose return if you're going to remove pressed in nipples)

drman929

iTrader: (4)

I just drilled and tapped my passenger head out to 3/8" NPT. Was stressful at first, but wound up going great. just use grease on the tip of your bit and tap to catch the shavings and you'll be fine.

SMAX

iTrader: (11)

lol I did the same thing and it was stressful.

bczee

iTrader: (12)

I just took a drill bit with a lot of grease, a shop vacuum and just took too it in about 3 steps to make sure that I got all of the shavings out with the shop vacuum.

grease bit, Drill, vacuum for shavings, clean bit of shaving and start over.. 2 or 3 times. Pretty sure I got all of the shavings. Then just tap and screw in the sender.

Horsepwraddict

iTrader: (12)

ya, I did mine when the engine was out of the truck so it wasn't a problem for me.

thunderstruck507

iTrader: (18)

why are there 2 temp sending units on these? one in the front driver head and one in rear pass head

just curious

dsrour

I only have one factory (3 wire) sender on my 98 ls1. Has anyone tried using the green wire on this circuit which I think is a thermistor.

SMAX

iTrader: (11)

there aren't two. There is only one and the other is plugged. It is just that the heads are not bank specific so they are all drilled and tapped the same.

garretthes

I was wondering if I could use an older single wire sensor and attach it to my factory gauge. Anyone do this?

ls1nova71

iTrader: (4)

It would work fine, but like others have said, you have to figure out what thread the old sender is, and drill and tap the head for the larger sender.

phatbudde

I did the same as dsrour. Easy access and a true reading at the thermostat