# 1.8t coolant temp with 8v cluster



## Stroked1.8t (Jan 9, 2004)

just did a swap, 1.8t in an MKII, connected the coolant gauge to the sensor and it climbs to what would be overheating. I am assuming the 8v sensor and the 1.8t sensor work on different resistance and that is why my gauge climbs so high. 
Does anyone know what size resistor I can put inline to get it working properly?


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## Nihilator (Nov 6, 2004)

*Re: 1.8t coolant temp with 8v cluster (Stroked1.8t)*

The green-top temperature sensor for the 1.8t is not particularly expensive, maybe $8-$10, so isn't it probably worth the hassle just to buy the new temp sensor?
--Chris


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## Stroked1.8t (Jan 9, 2004)

I don't think you are understanding.
8v coolant temp and 8v cluster work fine together, they were designed to work together. 
now I have a 1.8t engine that uses a 1.8t coolant temp sensor, but I still have the 8v cluster, they weren't designed to work together. 
nothing is wrong with my current coolant temp sensor.


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## Veedubgti (Mar 5, 2001)

*Re: (Stroked1.8t)*

ABA coolant temp sensor for AEB swap in Mk2, trust me.


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## Stroked1.8t (Jan 9, 2004)

*Re: (Veedubgti)*

its not an AEB, is the connector different between the ABA collant sensor and the AWP?
also is there 4 pins on the ABA coolant temp?


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## Veedubgti (Mar 5, 2001)

*Re: (Stroked1.8t)*

Yes its 4 pin. 2 are for ECU, 2 are for gauge. The values for the ECU are the same but the values are different for the gauge. They are the correct values for an 8V cluster. The AEB/ABA sensors are square shaped and will not fit an AWP harness w/o changing the connector.


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## Stroked1.8t (Jan 9, 2004)

*Re: (Veedubgti)*

cool, great info. just need to source an ABA/AEB coolant temp sensor connector now.
you think you could send me some pictures of your boost piping and your intercooler. I get all piping, intercooler, t bolt clamps and silicome couplings from DHL tomorrow and plan on putting it in this weekend. Would like to see what you have done with yours.
[email protected]


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## sdezego (Apr 23, 2004)

*Re: (Veedubgti)*


_Quote, originally posted by *Veedubgti* »_Yes its 4 pin. 2 are for ECU, 2 are for gauge. The values for the ECU are the same but the values are different for the gauge. They are the correct values for an 8V cluster. The AEB/ABA sensors are square shaped and will not fit an AWP harness w/o changing the connector.

This is good to know because no one ever answered this for me in a couple of previous posts. It sounds like you have first hand experience and it did not work? I was planning on setting up a pot of water and calculating the resistance curves, but you saved me the trouble.
I ended up buying both the Green D shaped 4 pin Sensor for the AWP as well as the Square 4 Pin Blue Sensor for the AEB (Thinking at least one of them would be good to go for the gauge). ECU is less important for me because I am running MSnS and can program any ECU CTS curve.
Shawn


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## Veedubgti (Mar 5, 2001)

*Re: (sdezego)*

ABA sensor is compatable with both the Mk2 temp gauge and the 1.8t ECU. Its the ticket.
Running an AEB sensor on this setup makes the Mk2 temp gauge skyrocket.


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## sdezego (Apr 23, 2004)

*Re: (Veedubgti)*

Thanks http://****************.com/smile/emthup.gif


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## sdezego (Apr 23, 2004)

*Re: (sdezego)*

Is this the one you are referring to from the ABA? Yellow?


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## Veedubgti (Mar 5, 2001)

*Re: (sdezego)*

precisely


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## sdezego (Apr 23, 2004)

*Re: (Veedubgti)*

A little update to this thread.
Last night I took 4 sensors, a pot of Ice water to start, a Thermocouple along with a thermometer, an Ohm Meter and a few







s
I logged temp vs resistance (about every 5*F) from 32*F - ~212*F
I just got done plotting them (1 for ECU and 1 for Temp Gage) out and here is what I found:
There is no significant difference with ANY VW sensors between ECU sensors or between Gauge Sensors. This is contrary to information that has been posted a few times, but the data does not lie. My data also corresponds directly with the Blue Corrado CTS from the Bentley.
Here is what I tested (ECU pins and Gauge pins is applicable):
- Corrado Black (Gauge) sensor.
- AEB (Passat Blue) 4 pin sensor
- ABA (Yellow Ring) 4 pin sensor (pictured above)
- AWP (Late 20v Green) 4 pin Sensor
The only thing I can say is possibly that people using some of the 4 pin sensors that have reported issues must have mixed up the ECU and Gage pins on the sensors or were using roached sensors. or possibly using some oddball sensor that I did not test.
I will post everything in a separate thread a bit later,
Cheers,
Shawn




_Modified by sdezego at 2:49 PM 12-9-2006_


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## fast-forward (Nov 14, 2002)

*Re: (sdezego)*

I install TDIs into Vanagons. The ALH and BEW TDIs (1999 and later TDI) do exactly what you are describing to the Vanagon's temperature gauge. When you are at 93C operating temperature (measured with VAG-COM) the OE gauge feels the engine is too hot and the little LED will start to blink. If you place a 100 ohm resistor in line, the OE gauge goes very close to where it should be - this is the case at least for Vanagons and the MK-II Golf / Jetta.
Prost!


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## sdezego (Apr 23, 2004)

*Re: (fast-forward)*

I just installed the Blue AEB one just for giggles and tested it out. Sure enough, it did act a little strange as described. In looking at the range near operating temps, it is off from the Corrado Black one, but the ABA is off as well. 
It appears that the gauge is very sensitive around this area where small changes in resistance can affect the temp by say 15-20 degrees.
For example: at 172*F the resistance is:
PG - ABA - AWP - AEB
171 - 198 - 183 - 187 (ohms)

You can see that the AWP is the closest and the AEB is next, but based on the values that I see on the Gauge in the car (~ +15*F), I am agreeing that a 100ohm resistor might be perfect, but I can not explain why yet.








I am going to try the ABA *as was recommended* and might even try the resistor as well.

*NOTE:* I am not trying to re-invent the wheel here, just trying to find options for folks out there. The late AWP sensor is also about 1/2 the price of the ABA one. Still pretty cheap in relative terms though.
Shawn


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## sdezego (Apr 23, 2004)

*Re: (sdezego)*

ok, I didn't try the resistor on the Blue AEB and just tried the Late Green 20v AWP one that I had.
It was worse and the gauge went all the way up at operating temp and the light started blinking.
I then picked up a couple of various resistors, tried a few and settled on a 50-55ohm setup that works perfect in the Corrado to replace the Black sender.
I am still going to post all of the data for the various sensors, pin outs etc.
Also going to try the Yellow Ringed ABA one as suggested, but since the resistance if off from the Corrado, I am not sure how that one will work w/o resistors. I'll check it out http://****************.com/smile/emthup.gif
Shawn


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## sdezego (Apr 23, 2004)

*Re: (sdezego)*

Link to the Full Temp Sensor Data thread that i just created. 
http://forums.vwvortex.com/zerothread?id=2975062


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## bens_cab (Oct 30, 2005)

use 20vt temp sender fit an inline 470ohm resistor inline works a treat


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## sdezego (Apr 23, 2004)

*Re: (bens_cab)*


_Quote, originally posted by *bens_cab* »_use 20vt temp sender fit an inline 470ohm resistor inline works a treat 


470 or 47 ohm? I found that the 1.8t (Green one) works perfect with the Corrado Gauge using about a 55ohm.
S


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## Audi4u (Jun 29, 2002)

*Re: (sdezego)*

This may or may not be obvious, but if the the ecu side of the sensor is the same for all the cars, why not just run the one that goes with the cars cluster?
And if the car uses a seperate sensor, then you can get the aeb coolant water outlet pipe with the spot for two sensors or get the one from a 2000 2.0 that has an extra location in the junction pipe to the over flow.
sdezego did some great testing in the other thread. I think brand new sensors shhould have been used because of aging.
Adding resistors to a circuit that doesnt have a linear resitance is also not a good idea. If you watertemp gets to say 230 the gauge might only show 210, because the resistor is adding that much more resistance.
Andre


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## sdezego (Apr 23, 2004)

*Re: (Audi4u)*

ahhh, I hadn't seen the 2000 2.0 coolant hose with the spot for the Sensor but just looked it up. Definitely looks like an additional option.
As far as the AEB flange, from what I recall when looking at it, it will not work properly with a transverse engine, but I could be wrong.
Also, all new sensors were used with the exception of the Black Gauge Sender.


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## Audi4u (Jun 29, 2002)

No matter what, you were thorough with your testing. And if noone else on vortex appreciates it, I do!
Thank for your time invested, its good info to know.
http://****************.com/smile/emthup.gif


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## nexus-dk (Aug 16, 2005)

*Re: (sdezego)*

i use the 20vt AGU temp sensor to my Mk.3 cluster no problem at all


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## JCdubber (Sep 12, 2005)

*Re: (nexus-dk)*

Im having the same problem right now and need to find a sensor for the MKIII cluster using a MKIV ECM. If the AGU sensor works I will probably use that one. Can you measure the resistance at room temp for me?


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