Coolant temp sensor comparison

[R.O.R-2.0]

ok, so i just swapped in a mk1 diesel in my mk2, and the only thing that isnt hooked up, is the temp gauge. i was wondering if the temp senders have the same resistance as each other, just with different style connectors?

or if the sensors are both physically, and internally different.. i dont have bentlys for either car, so i cant help myself, otherwise i would.

didnt figure the search function would turn anything up either..

and for the record, this is the LATE style mk2 coolant sensor.. the one that clips in the plastic neck. and im looking to see if they have the same resistance as the little pill sized sensors..

if i can, im going to make an adapter harness that goes from the old style sensor to the new style plug in. provided the sensors have the same resistance slopes..

what do you gentleman have to say about this?

i am NOT going to swap on a plastic water neck. it is not an option.

[8v-of-fury]

So you have the Metal neck with the one wire coolant sensor?

And your car has the two wire plastic plug?

Easy Peasy. The senders are the same, through mk1-3 as far as I have seen as they all work the same 70-110 temperature gauge. So here's what you do Lob that connector off, get rid of the ground wire and hook the other one up wit ha spade to the mk1 coolant neck. DONE.

The only reason the mk2 is a two wire is because the neck is plastic and it has to ground out elsewhere. The mk1 coolant temp system grounds through the metal coolant neck. I have an mk2 engine in my mk1 (opposite of you) and I have the 1 wire for the coolant going to the one wire of the two wire plug and the other ground to my valve cover stud.

[ORCoaster]

Do they both have the same resistance rating?  Seems that would be key for having the gauge show the needle in the right place.  Speaking of which does the 70-100 range you mention start on the first bar on the gauge?  If I give 5 degrees for each bar I pretty well align with the other gauge I have that tells me actual degrees C.  I run on 4 to 5 marks up all the time and that goes well with the 85 to 90 C on the gauge. 

The red would come in at 100 C which would be in the danger zone. 

Or is this just an accidental alignment of my equipment and not a standard others could use?

[R.O.R-2.0]

Do they both have the same resistance rating?  Seems that would be key for having the gauge show the needle in the right place.  Speaking of which does the 70-100 range you mention start on the first bar on the gauge?  If I give 5 degrees for each bar I pretty well align with the other gauge I have that tells me actual degrees C.  I run on 4 to 5 marks up all the time and that goes well with the 85 to 90 C on the gauge. 

The red would come in at 100 C which would be in the danger zone. 

Or is this just an accidental alignment of my equipment and not a standard others could use?

the mk1 temp sensor works fine with the mk2 gauge.. its got the same resistance slope, and just requires you cutting a plug off, and hiding a ground wire, then putting a female spade terminal on the signal wire. was a rediculously simple task. took maybe 5 mins to complete..

as for your gauges, i would imagine that its just co-incidence.. ive only seen a few VW gauge clusters that actually had the same reading  at the same temp..

[8v-of-fury]

I definitely seen the VW gauges being standard between 70-110c.

I do believe the mk1 and mk2 to be the same as I did not notice a difference on my mk1 cluster between the mk1 and mk2 sensors.

[slavik19]

hey guys im also doing a 1.6d swap. mk1 diesel into mk2 gli
my gli temp sensor is a 3 wire connection mk1 is 2 wire.
it think can someone show some pictures?
im not even sure which one is the temp sensor. there is a few sensors on coolant flangs..
thanks in advance

[8v-of-fury]

The temp sensor should not be a 3 wire in the mk2 gli.. What would the third wire be?? Slavik, any chance you are slavik and are from Slovakia? lol

[R.O.R-2.0]

temp sensor is 2 wire plug. yellow and brown wires going to the plug. it should be on the main underhood harness, not the one that the ECU is connected to..

again, temp sensor is not 3 wires..

[slavik19]

The temp sensor should not be a 3 wire in the mk2 gli.. What would the third wire be?? Slavik, any chance you are slavik and are from Slovakia? lol

ill check again. to many wires ill figure it out one day.

yes im a slavik and no im ukrainain, but lived in the states most of my life.

temp sensor is 2 wire plug. yellow and brown wires going to the plug. it should be on the main underhood harness, not the one that the ECU is connected to..

thanks ill check again.
again, temp sensor is not 3 wires..

[R.O.R-2.0]

do you still have the ECU, and ECU harness in the car? because if you do, pull it out and get rid of it. its not needed AT ALL..

all the connections you will need are on the small harness with the temp sender connector, and the 2 oil pressure switch connectors. along with the reverse switch connector..

everything you need besides fuel stop solenoid power is in that small harness..

[slavik19]

do you still have the ECU, and ECU harness in the car? because if you do, pull it out and get rid of it. its not needed AT ALL..

all the connections you will need are on the small harness with the temp sender connector, and the 2 oil pressure switch connectors. along with the reverse switch connector..

everything you need besides fuel stop solenoid power is in that small harness..

so its safe to remove everything! but that harness will do. i hate all the mess. what do the fans connect to? how do they work on a mk2? do i need to connect the wireing to the coolant temp on the engine itself? or it runs on its own, signal from the sensor on the raditor and other end to the battery and fan motor.

[R.O.R-2.0]

do you still have the ECU, and ECU harness in the car? because if you do, pull it out and get rid of it. its not needed AT ALL..

all the connections you will need are on the small harness with the temp sender connector, and the 2 oil pressure switch connectors. along with the reverse switch connector..

everything you need besides fuel stop solenoid power is in that small harness..

so its safe to remove everything! but that harness will do. i hate all the mess. what do the fans connect to? how do they work on a mk2? do i need to connect the wireing to the coolant temp on the engine itself? or it runs on its own, signal from the sensor on the raditor and other end to the battery and fan motor.

you can remove the ECU, and harness that connects to it.. mines in a box in the back of my shop, and my car runs.. like i said, everything you need is part of the vehicle harness, and will stay in the car as you remove the ECU/engine harness.. it really cleans everything up when you take all that crap out..

the fan is also part of the vehicle harness.. mines still working fine, surprisingly..

all i had to do, was tap into the digifant power wire for injection pump power.. and then rig up a glow plug relay, and switch. i used a momentary contact switch that returns to the off position when you let your finger off it, so the glow plugs can not accidentally be left on..

un plug everything, do not cut.. thats ghetto fab construction!

[slavik19]

do you still have the ECU, and ECU harness in the car? because if you do, pull it out and get rid of it. its not needed AT ALL..

all the connections you will need are on the small harness with the temp sender connector, and the 2 oil pressure switch connectors. along with the reverse switch connector..

everything you need besides fuel stop solenoid power is in that small harness..

so its safe to remove everything! but that harness will do. i hate all the mess. what do the fans connect to? how do they work on a mk2? do i need to connect the wireing to the coolant temp on the engine itself? or it runs on its own, signal from the sensor on the raditor and other end to the battery and fan motor.

you can remove the ECU, and harness that connects to it.. mines in a box in the back of my shop, and my car runs.. like i said, everything you need is part of the vehicle harness, and will stay in the car as you remove the ECU/engine harness.. it really cleans everything up when you take all that crap out..

the fan is also part of the vehicle harness.. mines still working fine, surprisingly..

all i had to do, was tap into the digifant power wire for injection pump power.. and then rig up a glow plug relay, and switch. i used a momentary contact switch that returns to the off position when you let your finger off it, so the glow plugs can not accidentally be left on..

un plug everything, do not cut.. thats ghetto fab construction!

ohh i will be removing everything.
after i fix my head its leaking oil. going take the valve cover off tommarrow to see if the bolts are lose.