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Wed Feb 15, 2017 2:17 pm

Driving into work this morning I noticed that my temperature gauge in the console isn't working. I've seen some other threads on the same problem so I'll try and look at it this weekend.

I've got a Scangauge and it has a Water/Coolant temperature option, the manual says A vehicle with a 50/50 mix of coolant and water will not boil over until about 265 ̊ F at sea level. This will be reduced at higher elevations.

My question is what should a reasonable temperature be for a 1.8T?

Thanks in advance!

-- T

1990 Multivan/Weekender Auto SHA 1.8T

Wed Feb 15, 2017 2:26 pm

Since you have an SHA conversion I'd give Seth a call and ask him what you should expect. :D

Wed Feb 15, 2017 2:31 pm

Fully warmed up I will see 188/194 range.

There's several different quality types of t-stats btw.
I had a t-stat that only hit a high of 188, usually 186-184 which to me is a little too cool.
I didn't realize it was in early failure mode.
Then it only hit 179, so I pulled it.

I wanted to get a Bosch, but none were immediately available.
Comparing available units at Napa, I saw quite a difference in wire thickness, corresponding to price. :roll:

Wed Feb 15, 2017 2:50 pm

I have an SAH 1.8T as well. Have been noticing low coolant temps. Talked to SAH and they install 71C thermostats due to stock water pump not able to push around all our exact coolant. I put in a stock dealer 188F (87C) thermostat, Davies Craig Aux water pump and controller and now see 198F even in stop and go traffic (San Fran Area, CA). Waiting for a hot day to see how the pump combats overheating.

Wed Feb 15, 2017 6:29 pm

I don't have a SAH, I have a home brew AEB 1.8t stage 1 chip.

my normal cruise temp is 205/209f and 209/215f
it varies if/when I have the front heater on/open.

I have a water to air intercooler in front of my radiator.
temps are read at the head outlet, and my turbo coolant flows into my coolant bottle, right back into the waterpump. (constant flow)

what IATs do you see normally? how much different than ambiant temps?

Wed Feb 15, 2017 8:49 pm

Thanks for all the info everyone!

My console gauge worked on the way home from work tonight and it seemed to be just fine.

The ScanGauge temp was between 186-188.

Wed Feb 15, 2017 9:07 pm

tgraham wrote: Thanks for all the info everyone!

My console gauge worked on the way home from work tonight and it seemed to be just fine.

The ScanGauge temp was between 186-188.
I've got a SAH 1.8 with scanguage and I mostly run under or around 190 around town grocery getting.

Wed Feb 15, 2017 9:10 pm

If it goes over 215 that's bad

Wed Feb 15, 2017 9:18 pm

I have a SAH 1.8T with a ScanGauge and in the "winter" with ambient temps at 45-60F I see my van running mostly around 185F. In the summer I see operating temps between 185-215F.

I've asked Stephan about operating temps and this is what he said...

"Normal = 175-225F. Pull over and idle at 1500 RPMs when the ScanGauge hits 235F."

Wed Feb 15, 2017 9:22 pm

235 is extremely high for the 1.8t. You could do some reading on the VW vortex forums. I would pull over above 220-225. Just saying...

Thu Feb 16, 2017 10:32 am

danfromsyr wrote: I don't have a SAH, I have a home brew AEB 1.8t stage 1 chip.

my normal cruise temp is 205/209f and 209/215f
it varies if/when I have the front heater on/open.

I have a water to air intercooler in front of my radiator.
temps are read at the head outlet

This is my scenario 100%. I'm not worried about it in the least.

Thu Feb 16, 2017 6:05 pm

My AWP 1.8T normally runs at 188 degrees except for really warm weather where 194-202 degrees is typical. I've seen it get as hot as 212 but never higher.

To note, as a comparison, 188 is just below midway on the stock Vanagon temperature gauge (just below the red light) for me.

BTW, interesting to hear some basis of comparison from others....Soon i'll have to ask about normal intake temperatures with the turbo..... :lol: :shock:

Bill

Sun Jan 26, 2020 2:49 pm

So my 1.8T rencetly had the engine coolant temp sensor (CTS) go haywire and I was unable to find anything specific to the 1.8T CTS failure on the Samba, so I thought I would do a quick write-up for the next poor devil trying to sort it out.
Van is a Syncro with a 1.8T AWP engine conversion, the van has run without a hitch since I have owned it, about 3 years and 30K miles. I am not the one who did the conversion, but the conversion is legit and nicely done.
First symptom : Coolant gauge reading low, used to be anchored over the LED, slowly started showing lower readings I originally thought the cluster was going bad because the fuel level has always read low. Eventually the needle ended up just staying at the bottom of the gauge.
Second symptom: difficult to start, turns over, after numerous tries it catches, then finally runs on a few cylinders, then runs okay, then after a minute idles and runs fine without missing.
Third symptom: Loss of power, mostly noticeable in fourth gear - the engine has always climbed hills with aplomb, became anemic, almost like the turbo was not providing any boost.
No trouble codes or check engine light came on while running poorly and hard to start. I guess things were not far enough out of parameters.
Symptoms are similar to a Mass Air Flow sensor going bad. Interestingly, you can unplug either sensor (like one at a time) to diagnose, if the sensor is causing the issue, the engine will start/run better with the sensor unplugged. FYI - unplugging the sensors will cause the check engine light to come on and need clearing.
The CTS has two sides, four pins, two feed the gauge and the other two talk to the engine ECU. In my case both sides failed close together.
I ordered a new sensor based on the engine/original vehicle but the sensor that showed up did not fit the harness connector. I am only guessing here, but I am thinking that the sensor I pulled out is better matched to the Vanagon temperature gauge, and still works with the AWP engines ECU? But it might be that this is the one that went with whomever did the harness for the conversion. I took the part number from the broken sensor and was able to order a replacement, made in China so I ordered two.
Part # is VW 6U0 919 501B
See Photos.
Bad Sensor cut open, Notice oil incursion

Old sensor, Note Sensor part number, this made in Germany

This is the (incorrect) sensor that came when I ordered to match the original VIN on the Jetta the engine came out of, it did not fit the conversion harness plug

New Sensor, now made in China, we'll see how long this lasts, I bought two, and am actively looking for a NOS German part

For reference, part exchange numbers

Sorry but I did not get any photos of the differences in the shape of the plug.
Hope this helps someone.
Doug

Sun Jan 26, 2020 5:16 pm

Interesting, since I just had my van towed to a shop and it *might* be related to the cts.

I'm curious, did you start the engine with the cts unplugged?
I didn't know that the engine could start with that unplugged.

Below is a link to a site where you can get the square 4 pin, if you're using the same as I do. (1999 AEB)

https://www.fcpeuro.com/products/audi-vw-engine-coolant-temperature-sensor-vag-059919501

Sun Jan 26, 2020 6:33 pm

dougnlina wrote: This is the (incorrect) sensor that came when I ordered to match the original VIN on the Jetta the engine came out of, it did not fit the conversion harness plug

That's the correct sensor for the AWP engine. If it were me, I'd replace the pigtail plug on the conversion harness and use the AWP sensor. It's proven to be a better part in the long run than the square-plug style for some reason.

Mon Jan 27, 2020 10:40 am

Its a regular Sensorama! I will order the FCP one with the square plugand see how that one looks, I'm not sure I want to molest the harness to use the stock sensor, its nicely done. I also found a German replacement for the sensor I removed.
Yes, I unplugged the CTS and the engine started right up like is usually does, with the sensor plugged in, it was very difficult to start. But CEL did come on.
BTW since replacing the bad sensor, the engine is running great, I am back to 20+ MPG which had been falling off to 17-18MPG.
DP

Mon Jan 27, 2020 12:03 pm

the dash gauge is not a good reference for what the ECM thinks the coolant temps are.
I run an obdII elm327 blue tooth device to a free Torque app on my phone.
it allows me to see what the coolant temp the ECU is registering.
the 4 pin connectors have to thermositors in them one for the dash gauge and one for the ECM.