Author Topic: Mk4 Golf Temp Sensor (AGN)  (Read 294 times)

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Offline dubdub

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Mk4 Golf Temp Sensor (AGN)
« on: November 21, 2017, 09:17:24 pm »
Hey all,

Have had unreliable temp readings for some time now, so figured it was time to buy a new sender unit. Have taken the one in it out a few times and given it a clean, which seems to help (may just be luck also), but the gauge has gone back to reading nil, or 3/4 of what it normally would. (normally points straight up at 90) This is a 1.8 non turbo 1998 AGN car. Any suggestions for a good place to order a replacement part, as I can fit it myself easily enough.

Also curious, I've been having stalling problems lately, even at speed i.e 80/90 km/h which isn't much fun, any way it could be related to this sender? The stalling is very intermittent, so figured I would work on the sensor first as it clearly has a problem and go from there. The engine light has never come on.

Cheers


Offline the phantom

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Re: Mk4 Golf Temp Sensor (AGN)
« Reply #1 on: November 21, 2017, 09:29:14 pm »
cleaning the throttle body might help the engine cutting out
Land Transport New Zealand, taking the fun out of driving since August 2008

Offline Worms

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Re: Mk4 Golf Temp Sensor (AGN)
« Reply #2 on: November 22, 2017, 06:41:03 am »
Is it really the gauge reading wrong, or is the thermostat poked and it's running cool a lot of the time???

it may move up and down, if the thermostat is stuck open. Stuck in traffic, it may creep up, and cruising at decent speed, it may move back down.

Offline dubdub

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Re: Mk4 Golf Temp Sensor (AGN)
« Reply #3 on: November 22, 2017, 01:10:42 pm »
Is it really the gauge reading wrong, or is the thermostat poked and it's running cool a lot of the time???

it may move up and down, if the thermostat is stuck open. Stuck in traffic, it may creep up, and cruising at decent speed, it may move back down.

It was stuck on 0 for quite a bit, more often than not and my taking it out and fiddling with it seems to have made it better albeit not perfect. Often its fine and stays bang on at 90. Seems to be a bit random from week to week. I assume when thermostats get stuck open they somewhat remain in that state?

Offline dubdub

  • Posts: 7
Re: Mk4 Golf Temp Sensor (AGN)
« Reply #4 on: November 22, 2017, 01:16:45 pm »
cleaning the throttle body might help the engine cutting out

Good call, actually the garage did that a few months back while I had them check for error codes (weren't any). For a little while it seemed to have helped, but the gremlins have crept back. Are throttle bodies a known problem?

I was heading to Queenstown this weekend, and while dying at 80-90 km/h i.e the car was jerking madly I was able to recover by flooring it. It carried on like this for about 10 kms before Tekapo, stopped for lunch there and it never repeated it again for the rest of the journey south, or back to Chch. Its kinda annoying. Other times it occurs its when I take the gas off when pulling into our neighborhood. Next thing the car is dead. Always starts immediately again though.  The crank angle sensor packed a sad about a year or so ago, it felt like a different problem as it would just randomly die and not start again for a period of time.


Offline the phantom

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Re: Mk4 Golf Temp Sensor (AGN)
« Reply #5 on: November 22, 2017, 03:55:20 pm »
Good call, actually the garage did that a few months back while I had them check for error codes (weren't any). For a little while it seemed to have helped, but the gremlins have crept back. Are throttle bodies a known problem?

I was heading to Queenstown this weekend, and while dying at 80-90 km/h i.e the car was jerking madly I was able to recover by flooring it. It carried on like this for about 10 kms before Tekapo, stopped for lunch there and it never repeated it again for the rest of the journey south, or back to Chch. Its kinda annoying. Other times it occurs its when I take the gas off when pulling into our neighborhood. Next thing the car is dead. Always starts immediately again though.  The crank angle sensor packed a sad about a year or so ago, it felt like a different problem as it would just randomly die and not start again for a period of time.

they do need periodic cleaning, I know mine needs to be done when there's a hesitation it momentarily cuts out under load, quick easy job worth doing even if it's not the cause
Land Transport New Zealand, taking the fun out of driving since August 2008

Offline dubdub

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Re: Mk4 Golf Temp Sensor (AGN)
« Reply #6 on: November 23, 2017, 05:31:59 pm »
Thanks for that.

Curious, anyone know if those bluetooth OBD2 diagnostics tools work on the VW stuff? Seems like it will depend on the protocol the car uses, alas struggling to find a reliable list.

Offline vdubdave

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Re: Mk4 Golf Temp Sensor (AGN)
« Reply #7 on: November 24, 2017, 07:45:51 am »
I have two of the obd2 dongles - a Carista and an OBDLinkMX one....

They both work (sort of)... Can sometimes take about 3 attempts to get them to connect. These allow me to read and reset error codes and create my own dashboard (to view engine air intake temp)...

It's how I know my water/air charge cooling system drops the intake temp from 62 deg down to 32 deg!

There are plenty of apps available obdlink fusion Carista to name a few.
82 GTi Cabriolet EG engine
82 GTi Pretender PG engine
03 Supercharged V6 24v 4 Motion

Offline dubdub

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Re: Mk4 Golf Temp Sensor (AGN)
« Reply #8 on: December 11, 2017, 12:50:29 pm »
I finally got one of the USB cable units from Trademe, which came with a demo version of VAGCOM. Works o.k, albeit a little quirky.

I keep getting a P0102 fault code (MAF low input or something), and I know the MAF was cleaned not too long ago.  Guessing now I've done 220k kms in it I can expect things like this to go wrong.