Td5 additional gauges

**LyleC** · 12th July 2021, 09:58 PM

So my brother has fitted some extra gauges in his 2001 130 Td5.
We have found a couple of issues, but one he wanted me to ask the brains trust here (because he doesn't have a computer) is:
Engine oil temperature seems to read high.
He has connected at the oil pressure switch location on the oil cooler housing.
I think he needs some heat shielding from the exhaust manifold and turbo.
He has the plumbing coming out of the pressure switch connection point then right angle upwards with connections for oil temperature, oil pressure and original oil pressure switch.
Anyone have experience with this?

**shack** · 12th July 2021, 10:21 PM

Define "high"

**LyleC** · 14th July 2021, 06:54 AM

I think he said 120 C on 1 hour his drive home after the install at my place.

**AK83** · 14th July 2021, 05:58 PM

That does sound high.

How heavy is it? how heavy are his boots?(or at least his right boot?

)

I have a oil temp gauge on my Tdi, as well as pressure and a few others too.
Oil temp in average ambient conditions basically follows coolant temps.

eg. say 79°C on the coolant, I usually see about 60-70°C on the oil temp. My oil temp sensor is nowhere near any excessive heat producing ancillaries as with his TD5 setup.
If I come up and over a long steepish climb (in a Tdi, every climb is long and steepish tho!) ... coolant may rise just a few degrees, say 5° to low 80's .. very occasionally maybe 90 ish .. but oil rises by more.
If oil temp is about 5-10°C lower than coolant, after this long steep climb(usually end up in 3rd in my Auto) say 2750-3000 RPM with approx 3/4 right pedal .. oil can end up equal to coolant temp, and a few times in quite hot 40-ish ambient conditions I've seen oil pass coolant temps. IIRC it may have maxed at about 100 give or take a few degrees. Never seen 120 tho ... even when I did have some coolant issues in my D1, and coolant sometimes hit up into the 115°C range.

I've also noted that oil takes longer too build up heat, and also longer to cool down again.
So in those instances where coolant may have peaked at 117°C .. and I chickened right out and dropped a lot of speed and hit the downward side .. coolant will drop in a few minutes, back down to say mid 80's but oil will still hold in the 100 range, high 90's for a while longer.

could be that the location of the sensor may be affected by turbo and exhaust as already said. Have you guys tried to run the car with the turbo heat shield removed too? I can't remember how easy/hard it is to remove, but this may reveal some useful info before you try more elaborate alternatives.

Does it run that high all the time, a lot of the time, sometimes .. only in very hot ambient temps?

Does he run a coolant temp gauge that displays temps. I have no idea how accurate defender coolant temp gauge is, but FWIW, disco temp gauges are pretty much useless info for the operator.
If the coolant is running up into the 120°C region, then it follows that the oil temp would be similar .. coolant is used to help cool(and heat) the oil via the oil cooler.

**LyleC** · 15th July 2021, 06:58 AM

Thanks for the reply.
I'll have to check with him how this temperature is going other than his first drive home with this set-up.
Your experience is more like what I thought we should see.
I'll post here when we have progress.
Cheers, Lyle

**AK83** · 15th July 2021, 05:09 PM

Also note that sensors need to be matched to gauges to work correctly too!

Can we assume a VDO setup?
Was it bought as a matched set, or were parts bought here and there.

If not VDO, what brand.
If Chinese-ium branded .. take the accuracy of them with a grain of salt too. May well be accurate, but don't rely on it.

But on the topic of matched sensor and gauge, or is important to get right.

You may well already know this, but better not to assume stuff if you don't know the person nor their understanding of stuff and experience level.

VDO have various sensors and gauges, the two most common types you find easily say on ebay may be rated 50-150°C or 40-120°C
These are very common in the 2" round gauge format.
You can connect a 40-120 sensor to a 50-150 gauge, but it will read high(I think).
The sensor only sends a resistance value to the gauge, and the gauge responds with either a digtial readout or needle response accordingly.

In saying that, really poor quality wires or connectors or earthing, or loose connections will cause the gauge to mis read what the sensor is sending.. as it tries to 'send a resistance value to the gauge, a really crappily connected or wired fitment will cause this.

That is: how close is the wire from sensor to gauge to the hot parts of the engine? be mindful that heat in wires increases resistance through it .. and resistance is what the gauge is trying to measure from the sensor. if you increase the resistance through the wire, then gauge will be slightly inaccurate. Another possible solution is some temp heat insulation of the wire, or reroute it further from any possible excessive heat source.

Being a TD5, do you know if it's been mapped, or has your mate mapped it?
Does he have a pyrometer/exhaust temp gauge(EGT) fitted?

...anyhow, hope this also helps.

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