D24 - Can't solve temperature problem

[Maciek4530]

Originally Posted by ngoma

I don't know if the diesel versions of the temperature sensor and gauge are different from the gasser versions but there was some extra circuitry involved in the model years of your samples that tampered with the "true" readings that artificially kept the needle in the middle.

This is why I wanted you to take readings with an IR thermometer, so you could easily verify actual temperatures. Can you borrow one? You could read the temperature of the temperature sensor itself and compare it to the gauge.

"1986-1993 240 models are equipped with circuitry that is designed to keep the coolant temp gauge needle positioned in the normal zone (9:00 position) even if the engine is running a bit hot. The idea is to prevent minor variations in coolant temp from causing worry for the driver. As these cars age a common problem is the failure of the circuit board and connectors resulting in erratic readings or no reading at all. We have put together a simple bypass harness that reverts the function back to the earlier trouble-free design."

From
https://www.ipdusa.com/products/5670...-Volvo-1363117

More info:
https://cleanflametrap.com/tempFaker.html

https://www.youtube.com/watch?v=0AL4hphLMnE

Yep, but that is about US versions

In Europe we don't have system like this (and we happy abut that ) - we know exacly about all small changes in water temperature basis on gauge.

I try to borrowe IR thermometer

[Maciek4530]

Everything was ok 3 days... Now my radiator got a hole next to upper hose....

It could be problem since start of cooling problem?

[ngoma]

So, what fixed the temperature problem for those three days?

[Maciek4530]

Originally Posted by ngoma

So, what fixed the temperature problem for those three days?

Other temp gauge... I though...

Now i don't know sh*t.

My friend borrowed me early D24 radiator, i test it and find out if it was luck that everything seems normal but when coolant leak appears temp gauge get up to 3/4 of the scale (i stopped after going uphill as always).

Today i change steering joint (to make car maybe a little easy to control - old one was so loose...)

And i put radiator from my friend. I let car idle and make it to operation temp. But ther was no heat in vents. After few mins on "normal" temp i drive 50m at my driveway front and backward forward and heat starts to going through vents (I register car 2 days ago and change license plate - need to buy new frames to mount them and test drive car tommorow).

After that i stoped on parking stop and temp goes to 3/4 of scale and then set on "normal" agine. After that i hold accelerator pedal for 1 or 2 mins at high revs. Temp gauge just move 1-2 mm and shake a little - nothing that normal person would observe.

Tommorow i mount new plates and try to drive it on the road. I'm scared that something really bad happening...

It's middle of fall, my red B230F 240 should be in storage and i should drive this winter beater since 3 weeks...

I need to ask how much will be cost to replace core in my old radiator or i need to weld that hole... But next one can appeard after 32 years of this radiator existance...

[Maciek4530]

Now i think about sensors agine - I change both my sensors to "old" ones - but front one, to gauge is "no name" with 111 stamp. Maybe it's him? I experience weird temp readings in my brother B200F 240 when i put new EPS sensor it shows that rebuild car overheat. Then i find out that: old owner put heater valve upside down (that's why there was no heat in car) and new sensor was wrong. Can somone give me correct VW/Audi coolant sensor number for display?

Maybe both: my new and "old" - no name sensors aren't correct fitted? Only rear sensor in car s VW/Audi old orginal temp sensor.

[ngoma]

So where are we now? Seems to me that we still really don't know engine temperatures if you are doubting the sensor and/or gauge. Were you able to borrow an IR thermometer?

[Maciek4530]

Now i need to make wise decisions.

Can't find anyone with IR thermometer, need to waste (a lot i think) money to rebuild my radiator, friend radiator is leaking too but less... and winter time change in 2 days...

After 3 days of testing (everything was ok) it happend agine at short drive:
- 4 mins to shop (10 min sitting)
- 3 mins to another shop (15 mins of sitting)
- 5 mins back home and temp gauge show almost red line... But as always never reach it.

Could be a radiator leak (my old one and friend one) cause temp problem like this?

And I'm almost at 1k km after headgasket rebuild so i need to torque it 90* more... And i'm scared of it - last step (90* after engine runs 30mins - hot) was hard to do with my tools and some of bolts squel and make my tool vibrater when torquing. I hope bolts don't snap...

[ngoma]

Originally Posted by Maciek4530

Could be a radiator leak (my old one and friend one) cause temp problem like this?

How do you know you have a temp problem?

Originally Posted by Maciek4530

And I'm almost at 1k km after headgasket rebuild so i need to torque it 90* more... And i'm scared of it - last step (90* after engine runs 30mins - hot) was hard to do with my tools and some of bolts squel and make my tool vibrater when torquing. I hope bolts don't snap...

Squealing, chatter, and creaking is normal. Use a cheater pipe on your breaker bar for better leverage and control.

[Maciek4530]

Originally Posted by ngoma

How do you know you have a temp problem?


Squealing, chatter, and creaking is normal. Use a cheater pipe on your breaker bar for better leverage and control.

First of all thank you for answering my stupid thread, most people left or don't answer at all

AD.1 You are correct. Probably it was not engine temp problem from start.

A drive car 2 weeks and have few observations:
- After clamp retight there is no leak at radiator - car is dry (from coolant, there is oil leak ofc)

- After longest drive (higway etc, fir 15-30min) both coolant hoses (upper/lower) are warm like they should be i think

- Day after upper hose clamp retight i drive to my friend and i think i comfirm that's all about wrong temp indication. After 5 min ther was normal temp, after 10 in traffic jam almost red line, at higway 3/4 of temp gauge, when i left higway temp drops below minimum...

I think it's not possible

So after that i start to investigate... And i think all D24 240's in europe habe temp faker. I didn't saw that befor but they have! PB cars don't have it but D24 got it. I ask guy with D24 to show mi his cluster. It have dot on it so it should be "0002" temp gauge. 0002 probably always with temp faker board so changing only temp gauge do nothing.

Today i remove temp faker board and connect pin 1 and 3. After drive gauge shows 1/3 of scale, then drops to around minimum. When i drive it hard it's few mm above minimum, when i drive steady and on flat it's exacly on minimum.

I find a forum thread that say:
"not all 240 gauges will have the same readout when the board is bypassed. In fact, the past 3 I have bypassed all read differently, even though coolant temps were a consistent 180F on all 3 vehicles. I had one that reads about 1/3 way up, one slightly over half, and one that reads 3/4 the way up.

The only way to be sure is to VERIFY coolant temps with another gauge, like an infrared thermometer."

So i think it's all about gauge - but still i need to veryfiy it like you said.

My cluster after faker board removal and with wire to 1 and 3 pin.

cae91f09-6726-464d-8915-ce7fb9033379.jpg

AD.2 Thank you. I ask few people about it - all said like you - it can happened even if i clean threads a little, put oil on them and zinc between bolt head and washer. It's getting closer to 1k km