Temp sender 200tdi vs 300tdi (and serpentine belt)

[finnarne]

I've just replaced my old 200tdi with a 300tdi with half the mileage in my Disco. And here is of course some small problems.

First test drive today, I drove my disco to work. 5.3 km, Before that, I had only had the car running for a few minutes in my driveway, just to check for leaks and stuff.

After 2 km I hear what think was the serpentine belt tearing at one or both sides. I think it's now down to 5 teeth(?), which is a bit few.

Then I started to pay (more) attention to the temp gauge. I noticed that it had moved a bit more than it used to with the 200tdi.

It almost hit the red area before i stopped at the parking lot. The serpentine belt is still 5 teeth, No leaks, and when I got out and checked an hour or so later, the coolant level was as I think it should be.

There was no warm air from the heater though.

The serpentine belt was a new Dayco. I think all the pulleys are tight, but will check before I leave for home at the end of the workday.

Any tips on the temp gauge/sender issue ? I found a post on another forum saying he had put (I think) a 100ohm resistor in series with the sender, and then it showed the correct temperature.

[lo-fi]

Measure the resistance of both senders in boiling water and compare. This will tell you what value resistor to use if they are different.

[finnarne]

I guess I would need to measure at several temperatures then ?

Question then is. On the 300tdi Disco there were an ECU. on the 200tdi no such. Are the ECU involved ?

Also, I'm thinking of replacing the speedometer and gauges of the 200tdi with the one from the 300tdi. How many of the signals could be used as is ?

[Tanuki]

Apparent overheating, belt issues, and no heat from heater?

Are you sure the water-pump is turning freely? And is the rotor still attached to the spindle? (I've had experience of the 2.5 BMW/Range-Rover lump where the rotor's dropped off the spindle inside the engine).

[elbekko]

The ECU on the 300TDi is only for EGR. The funny thing is its temperature sensor is in a much better spot than your gauge's. I wouldn't be surprised if the engine wasn't cooking by the time you saw your gauge creep up. Stupid design that seems almost designed to kill an engine with air locks.

Have you noticed I don't like the 300TDi's cooling system much?

[lo-fi]

I guess I would need to measure at several temperatures then ?

Question then is. On the 300tdi Disco there were an ECU. on the 200tdi no such. Are the ECU involved ?

Also, I'm thinking of replacing the speedometer and gauges of the 200tdi with the one from the 300tdi. How many of the signals could be used as is ?

You'll never get it right across the whole with a simple resistor. All you can hope for is to get the needle in the right place at the important point (proper operating temperature).

As others have suggested, it's quite possible you do have a cooling issue, but it'll be hard to narrow down whether this is really the case without a gauge you know gives current readings. Trust the heater - it's probably telling you something useful!

[finnarne]

I think the readings are not that far off, but I'll check with an infrared soon. I Agree on the heather.

As said, I've replaced my 200tdi with a 300tdi. It seemed to run OK before we took it out of the donor, but It's some months since it was last running. I had a problem with the belt tensioner when I was about to take out the servo pump of the donor. It was stuck. The bearings was ok, but it wouldnt flex, so I had to cut the serpentine belt.

When I had put the 300 into my car, and was about to mount a new belt, I remembered about the tensioner. I took the tensioner from the other 300tdi I have in my garage, that I originally had planed to put into my car. There is supposed to be a new tensioner somewhere in there as well, but I have to look...

I've started the engine a few times, first after only filling the engine with oil, then after adding coolant and mounting the belt. But I still had no oil on the gearbox, so it was only for a few seconds. Then again after mounting transfer case and exhaust, I allowed the engine to run a few minutes. Still no bumper nor propshafts, so it was only to check that the exhaust was ok. This was on Tuesday.

On wednesday I went to a club meeting to talk about building a trophy truck.

Thursday I worked on my car until 00:30, I think.

But I was sure I had fastened the pulleys on waterpump and servopump.

Well, at the end of the workday, I checked the pulleys and the belt. Finding one bolt on the servo-pulley that I could fingertighten. I called my neighbor/co-pilot and he came with a 10mm spanner. I tightened all 6 bolt before driving home. Stopped on the way and got 2 new belt, I think the make was goodyear. Costs an arm and a leg (50£ each, but got a 20% discount)

Made it all the way home, and checked the temperature again. I guess there still was some air locked inside the cooling system, when I arrived the temp gauge was at about halfway. Left it idling in my driveway a few minutes, and seemed like the thermostat was working. when idling in my driveway, the temperature lowered a bit, like normal. And there was warm air from the heather.

I'll have to replace the tensioner, just have to dig for a new one in my garage first. And I have to replace the belt.

So it looks like the gauge and the sensor works fine, and there was an air lock causing the raised temperature last morning.

[finnarne]

I also had to replace the water pump. I Tried to check the bearings and it felt fine when I installed the engine, but now, a few days after, it was ready to be replaced.

Had a longer test drive today, and things look better.

[lo-fi]

Good good. Hope the temp spike didn't do any damage!